Activator.CreateInstance Method

Definition

Namespace:

System

Assembly:

System.Runtime.dll

Creates an instance of the specified type using the constructor that best matches the specified parameters.

Overloads

CreateInstance(String, String, Boolean, BindingFlags, Binder, Object[], CultureInfo, Object[])	Creates an instance of the type whose name is specified, using the named assembly and the constructor that best matches the specified parameters.
CreateInstance(Type, BindingFlags, Binder, Object[], CultureInfo, Object[])	Creates an instance of the specified type using the constructor that best matches the specified parameters.
CreateInstance(Type, BindingFlags, Binder, Object[], CultureInfo)	Creates an instance of the specified type using the constructor that best matches the specified parameters.
CreateInstance(Type, Object[], Object[])	Creates an instance of the specified type using the constructor that best matches the specified parameters.
CreateInstance(String, String, Object[])	Creates an instance of the type whose name is specified, using the named assembly and parameterless constructor.
CreateInstance(Type, Object[])	Creates an instance of the specified type using the constructor that best matches the specified parameters.
CreateInstance(Type, Boolean)	Creates an instance of the specified type using that type's parameterless constructor.
CreateInstance(String, String)	Creates an instance of the type whose name is specified, using the named assembly and parameterless constructor.
CreateInstance(Type)	Creates an instance of the specified type using that type's parameterless constructor.
CreateInstance<T>()	Creates an instance of the type designated by the specified generic type parameter, using the parameterless constructor.

CreateInstance(String, String, Boolean, BindingFlags, Binder, Object[], CultureInfo, Object[])

Source:

Activator.RuntimeType.cs

Creates an instance of the type whose name is specified, using the named assembly and the constructor that best matches the specified parameters.

public:
 static System::Runtime::Remoting::ObjectHandle ^ CreateInstance(System::String ^ assemblyName, System::String ^ typeName, bool ignoreCase, System::Reflection::BindingFlags bindingAttr, System::Reflection::Binder ^ binder, cli::array <System::Object ^> ^ args, System::Globalization::CultureInfo ^ culture, cli::array <System::Object ^> ^ activationAttributes);

public static System.Runtime.Remoting.ObjectHandle? CreateInstance (string assemblyName, string typeName, bool ignoreCase, System.Reflection.BindingFlags bindingAttr, System.Reflection.Binder? binder, object?[]? args, System.Globalization.CultureInfo? culture, object?[]? activationAttributes);

static member CreateInstance : string * string * bool * System.Reflection.BindingFlags * System.Reflection.Binder * obj[] * System.Globalization.CultureInfo * obj[] -> System.Runtime.Remoting.ObjectHandle

Public Shared Function CreateInstance (assemblyName As String, typeName As String, ignoreCase As Boolean, bindingAttr As BindingFlags, binder As Binder, args As Object(), culture As CultureInfo, activationAttributes As Object()) As ObjectHandle

Parameters

assemblyName

String

The name of the assembly where the type named typeName is sought. If assemblyName is null, the executing assembly is searched.

typeName

String

The fully qualified name of the type to create an instance of.

ignoreCase

Boolean

true to specify that the search for typeName is not case-sensitive; false to specify that the search is case-sensitive.

bindingAttr

BindingFlags

A combination of zero or more bit flags that affect the search for the typeName constructor. If bindingAttr is zero, a case-sensitive search for public constructors is conducted.

binder

Binder

An object that uses bindingAttr and args to seek and identify the typeName constructor. If binder is null, the default binder is used.

args

Object[]

An array of arguments that match in number, order, and type the parameters of the constructor to invoke. If args is an empty array or null, the constructor that takes no parameters (the parameterless constructor) is invoked.

culture

CultureInfo

Culture-specific information that governs the coercion of args to the formal types declared for the typeName constructor. If culture is null, the CultureInfo for the current thread is used.

activationAttributes

Object[]

An array of one or more attributes that can participate in activation. This is typically an array that contains a single UrlAttribute object that specifies the URL that is required to activate a remote object.

This parameter is related to client-activated objects. Client activation is a legacy technology that is retained for backward compatibility but is not recommended for new development. Distributed applications should instead use Windows Communication Foundation.

Returns

ObjectHandle

A handle that must be unwrapped to access the newly created instance, or null for Nullable<T> instances with no value.

Exceptions

ArgumentNullException

typeName is null.

MissingMethodException

No matching constructor was found.

TypeLoadException

typeName was not found in assemblyName.

FileNotFoundException

assemblyName was not found.

MethodAccessException

The caller does not have permission to call this constructor.

MemberAccessException

Cannot create an instance of an abstract class, or this member was invoked with a late-binding mechanism.

TargetInvocationException

The constructor, which was invoked through reflection, threw an exception.

InvalidComObjectException

The COM type was not obtained through GetTypeFromProgID or GetTypeFromCLSID.

NotSupportedException

Creation of TypedReference, ArgIterator, Void, and RuntimeArgumentHandle types, or arrays of those types, is not supported.

-or-

activationAttributes is not an empty array, and the type being created does not derive from MarshalByRefObject.

-or-

The constructor that best matches args has varargs arguments.

BadImageFormatException

assemblyName is not a valid assembly.

-or-

The common language runtime (CLR) version 2.0 or later is currently loaded, and assemblyName was compiled for a version of the CLR that is later than the currently loaded version. Note that the .NET Framework versions 2.0, 3.0, and 3.5 all use CLR version 2.0.

FileLoadException

An assembly or module was loaded twice with two different evidences.

-or-

The assembly name or code base is invalid.

Remarks

Use ObjectHandle.Unwrap to unwrap the return value.

Note

Starting with .NET Framework 2.0, this method can be used to create nonpublic types and members if the caller has been granted ReflectionPermission with the ReflectionPermissionFlag.RestrictedMemberAccess flag and if the grant set of the assembly that contains the nonpublic types and members is restricted to the caller's grant set or to a subset thereof. (See Security Considerations for Reflection.) To use this functionality, your application should target .NET Framework 3.5 or later.

CreateInstance(Type, BindingFlags, Binder, Object[], CultureInfo, Object[])

Source:

Activator.RuntimeType.cs

Creates an instance of the specified type using the constructor that best matches the specified parameters.

public:
 static System::Object ^ CreateInstance(Type ^ type, System::Reflection::BindingFlags bindingAttr, System::Reflection::Binder ^ binder, cli::array <System::Object ^> ^ args, System::Globalization::CultureInfo ^ culture, cli::array <System::Object ^> ^ activationAttributes);

public static object? CreateInstance (Type type, System.Reflection.BindingFlags bindingAttr, System.Reflection.Binder? binder, object?[]? args, System.Globalization.CultureInfo? culture, object?[]? activationAttributes);

static member CreateInstance : Type * System.Reflection.BindingFlags * System.Reflection.Binder * obj[] * System.Globalization.CultureInfo * obj[] -> obj

Public Shared Function CreateInstance (type As Type, bindingAttr As BindingFlags, binder As Binder, args As Object(), culture As CultureInfo, activationAttributes As Object()) As Object

Parameters

type

Type

The type of object to create.

bindingAttr

BindingFlags

A combination of zero or more bit flags that affect the search for the type constructor. If bindingAttr is zero, a case-sensitive search for public constructors is conducted.

binder

Binder

An object that uses bindingAttr and args to seek and identify the type constructor. If binder is null, the default binder is used.

args

Object[]

An array of arguments that match in number, order, and type the parameters of the constructor to invoke. If args is an empty array or null, the constructor that takes no parameters (the parameterless constructor) is invoked.

culture

CultureInfo

Culture-specific information that governs the coercion of args to the formal types declared for the type constructor. If culture is null, the CultureInfo for the current thread is used.

activationAttributes

Object[]

An array of one or more attributes that can participate in activation. This is typically an array that contains a single UrlAttribute object that specifies the URL that is required to activate a remote object.

This parameter is related to client-activated objects. Client activation is a legacy technology that is retained for backward compatibility but is not recommended for new development. Distributed applications should instead use Windows Communication Foundation.

Returns

Object

A reference to the newly created object, or null for Nullable<T> instances with no value.

Exceptions

ArgumentNullException

type is null.

ArgumentException

type is not a RuntimeType.

-or-

type is an open generic type (that is, the ContainsGenericParameters property returns true).

NotSupportedException

type cannot be a TypeBuilder.

-or-

Creation of TypedReference, ArgIterator, Void, and RuntimeArgumentHandle types, or arrays of those types, is not supported.

-or-

activationAttributes is not an empty array, and the type being created does not derive from MarshalByRefObject.

-or-

The assembly that contains type is a dynamic assembly that was created with Save.

-or-

The constructor that best matches args has varargs arguments.

TargetInvocationException

The constructor being called throws an exception.

MethodAccessException

The caller does not have permission to call this constructor.

MemberAccessException

Cannot create an instance of an abstract class, or this member was invoked with a late-binding mechanism.

InvalidComObjectException

The COM type was not obtained through GetTypeFromProgID or GetTypeFromCLSID.

MissingMethodException

No matching constructor was found.

COMException

type is a COM object but the class identifier used to obtain the type is invalid, or the identified class is not registered.

TypeLoadException

type is not a valid type.

Remarks

The constructor to be invoked must provide the most specific match with the specified argument list under the constraints of the specified binder and binding attributes.

Note

Starting with .NET Framework 2.0, this method can be used to access nonpublic types and members if the caller has been granted ReflectionPermission with the ReflectionPermissionFlag.RestrictedMemberAccess flag and if the grant set of the nonpublic types and members is restricted to the caller's grant set or to a subset thereof. (See Security Considerations for Reflection.) To use this functionality, your application should target .NET Framework 3.5 or later.

CreateInstance(Type, BindingFlags, Binder, Object[], CultureInfo)

Source:

Activator.cs

Creates an instance of the specified type using the constructor that best matches the specified parameters.

public:
 static System::Object ^ CreateInstance(Type ^ type, System::Reflection::BindingFlags bindingAttr, System::Reflection::Binder ^ binder, cli::array <System::Object ^> ^ args, System::Globalization::CultureInfo ^ culture);

public static object? CreateInstance (Type type, System.Reflection.BindingFlags bindingAttr, System.Reflection.Binder? binder, object?[]? args, System.Globalization.CultureInfo? culture);

static member CreateInstance : Type * System.Reflection.BindingFlags * System.Reflection.Binder * obj[] * System.Globalization.CultureInfo -> obj

Public Shared Function CreateInstance (type As Type, bindingAttr As BindingFlags, binder As Binder, args As Object(), culture As CultureInfo) As Object

Parameters

type

Type

The type of object to create.

bindingAttr

BindingFlags

A combination of zero or more bit flags that affect the search for the type constructor. If bindingAttr is zero, a case-sensitive search for public constructors is conducted.

binder

Binder

An object that uses bindingAttr and args to seek and identify the type constructor. If binder is null, the default binder is used.

args

Object[]

An array of arguments that match in number, order, and type the parameters of the constructor to invoke. If args is an empty array or null, the constructor that takes no parameters (the parameterless constructor) is invoked.

culture

CultureInfo

Culture-specific information that governs the coercion of args to the formal types declared for the type constructor. If culture is null, the CultureInfo for the current thread is used.

Returns

Object

A reference to the newly created object, or null for Nullable<T> instances with no value.

Exceptions

ArgumentNullException

type is null.

ArgumentException

type is not a RuntimeType.

-or-

type is an open generic type (that is, the ContainsGenericParameters property returns true).

NotSupportedException

type cannot be a TypeBuilder.

-or-

Creation of TypedReference, ArgIterator, Void, and RuntimeArgumentHandle types, or arrays of those types, is not supported.

-or-

The assembly that contains type is a dynamic assembly that was created with Save.

-or-

The constructor that best matches args has varargs arguments.

TargetInvocationException

The constructor being called throws an exception.

MethodAccessException

The caller does not have permission to call this constructor.

MemberAccessException

Cannot create an instance of an abstract class, or this member was invoked with a late-binding mechanism.

InvalidComObjectException

The COM type was not obtained through GetTypeFromProgID or GetTypeFromCLSID.

MissingMethodException

No matching constructor was found.

COMException

type is a COM object but the class identifier used to obtain the type is invalid, or the identified class is not registered.

TypeLoadException

type is not a valid type.

Remarks

The constructor to be invoked must provide the most specific match with the specified argument list under the constraints of the specified binder and binding attributes.

Note

Starting with .NET Framework 2.0, this method can be used to access nonpublic types and members if the caller has been granted ReflectionPermission with the ReflectionPermissionFlag.RestrictedMemberAccess flag and if the grant set of the assembly that contains the nonpublic types and members is restricted to the caller's grant set or to a subset thereof. (See Security Considerations for Reflection.) To use this functionality, your application should target .NET Framework 3.5 or later.

CreateInstance(Type, Object[], Object[])

Source:

Activator.cs

Creates an instance of the specified type using the constructor that best matches the specified parameters.

public:
 static System::Object ^ CreateInstance(Type ^ type, cli::array <System::Object ^> ^ args, cli::array <System::Object ^> ^ activationAttributes);

public static object? CreateInstance (Type type, object?[]? args, object?[]? activationAttributes);

static member CreateInstance : Type * obj[] * obj[] -> obj

Public Shared Function CreateInstance (type As Type, args As Object(), activationAttributes As Object()) As Object

Parameters

type

Type

The type of object to create.

args

Object[]

An array of arguments that match in number, order, and type the parameters of the constructor to invoke. If args is an empty array or null, the constructor that takes no parameters (the parameterless constructor) is invoked.

activationAttributes

Object[]

An array of one or more attributes that can participate in activation. This is typically an array that contains a single UrlAttribute object that specifies the URL that is required to activate a remote object.

This parameter is related to client-activated objects. Client activation is a legacy technology that is retained for backward compatibility but is not recommended for new development. Distributed applications should instead use Windows Communication Foundation.

Returns

Object

A reference to the newly created object, or null for Nullable<T> instances with no value.

Exceptions

ArgumentNullException

type is null.

ArgumentException

type is not a RuntimeType.

-or-

type is an open generic type (that is, the ContainsGenericParameters property returns true).

NotSupportedException

type cannot be a TypeBuilder.

-or-

Creation of TypedReference, ArgIterator, Void, and RuntimeArgumentHandle types, or arrays of those types, is not supported.

-or-

activationAttributes is not an empty array, and the type being created does not derive from MarshalByRefObject.

-or-

The assembly that contains type is a dynamic assembly that was created with Save.

-or-

The constructor that best matches args has varargs arguments.

TargetInvocationException

The constructor being called throws an exception.

MethodAccessException

The caller does not have permission to call this constructor.

MemberAccessException

Cannot create an instance of an abstract class, or this member was invoked with a late-binding mechanism.

InvalidComObjectException

The COM type was not obtained through GetTypeFromProgID or GetTypeFromCLSID.

MissingMethodException

No matching public constructor was found.

COMException

type is a COM object but the class identifier used to obtain the type is invalid, or the identified class is not registered.

TypeLoadException

type is not a valid type.

Remarks

The constructor to be invoked must be accessible and must provide the most specific match with the specified argument list.

Note

Starting with .NET Framework 2.0, this method can be used to access nonpublic types if the caller has been granted ReflectionPermission with the ReflectionPermissionFlag.RestrictedMemberAccess flag and if the grant set of the assembly that contains the nonpublic types is restricted to the caller's grant set or to a subset thereof. (See Security Considerations for Reflection.) To use this functionality, your application should target .NET Framework 3.5 or later.

CreateInstance(String, String, Object[])

Source:

Activator.RuntimeType.cs

Creates an instance of the type whose name is specified, using the named assembly and parameterless constructor.

public:
 static System::Runtime::Remoting::ObjectHandle ^ CreateInstance(System::String ^ assemblyName, System::String ^ typeName, cli::array <System::Object ^> ^ activationAttributes);

public static System.Runtime.Remoting.ObjectHandle? CreateInstance (string assemblyName, string typeName, object?[]? activationAttributes);

static member CreateInstance : string * string * obj[] -> System.Runtime.Remoting.ObjectHandle

Public Shared Function CreateInstance (assemblyName As String, typeName As String, activationAttributes As Object()) As ObjectHandle

Parameters

assemblyName

String

The name of the assembly where the type named typeName is sought. If assemblyName is null, the executing assembly is searched.

typeName

String

The fully qualified name of the type to create an instance of.

activationAttributes

Object[]

An array of one or more attributes that can participate in activation. This is typically an array that contains a single UrlAttribute object that specifies the URL that is required to activate a remote object.

This parameter is related to client-activated objects. Client activation is a legacy technology that is retained for backward compatibility but is not recommended for new development. Distributed applications should instead use Windows Communication Foundation.

Returns

ObjectHandle

A handle that must be unwrapped to access the newly created object, or null for Nullable<T> instances.

Exceptions

ArgumentNullException

typeName is null.

MissingMethodException

No matching public constructor was found.

TypeLoadException

typeName was not found in assemblyName.

FileNotFoundException

assemblyName was not found.

MethodAccessException

The caller does not have permission to call this constructor.

MemberAccessException

Cannot create an instance of an abstract class, or this member was invoked with a late-binding mechanism.

InvalidComObjectException

The COM type was not obtained through GetTypeFromProgID or GetTypeFromCLSID.

NotSupportedException

Creation of TypedReference, ArgIterator, Void, and RuntimeArgumentHandle types, or arrays of those types, is not supported.

-or-

activationAttributes is not an empty array, and the type being created does not derive from MarshalByRefObject.

-or-

activationAttributes is not a UrlAttribute

array.

BadImageFormatException

assemblyName is not a valid assembly.

-or-

The common language runtime (CLR) version 2.0 or later is currently loaded, and assemblyName was compiled for a version of the CLR that is later than the currently loaded version. Note that the .NET Framework versions 2.0, 3.0, and 3.5 all use CLR version 2.0.

FileLoadException

An assembly or module was loaded twice with two different evidences.

-or-

The assembly name or code base is invalid.

TargetInvocationException

The invoked constructor throws an exception.

-or-

An error occurred when attempting remote activation in a target specified in activationAttributes.

Remarks

Use ObjectHandle.Unwrap to unwrap the return value.

Note

Starting with .NET Framework 2.0, this method can be used to create nonpublic types if the caller has been granted ReflectionPermission with the ReflectionPermissionFlag.RestrictedMemberAccess flag and if the grant set of the nonpublic types is restricted to the caller's grant set or to a subset thereof. (See Security Considerations for Reflection.) To use this functionality, your application should target .NET Framework 3.5 or later.

CreateInstance(Type, Object[])

Source:

Activator.cs

Creates an instance of the specified type using the constructor that best matches the specified parameters.

public:
 static System::Object ^ CreateInstance(Type ^ type, ... cli::array <System::Object ^> ^ args);

public static object? CreateInstance (Type type, params object?[]? args);

static member CreateInstance : Type * obj[] -> obj

Public Shared Function CreateInstance (type As Type, ParamArray args As Object()) As Object

Parameters

type

Type

The type of object to create.

args

Object[]

An array of arguments that match in number, order, and type the parameters of the constructor to invoke. If args is an empty array or null, the constructor that takes no parameters (the parameterless constructor) is invoked.

Returns

Object

A reference to the newly created object, or null for Nullable<T> instances with no value.

Exceptions

ArgumentNullException

type is null.

ArgumentException

type is not a RuntimeType.

-or-

type is an open generic type (that is, the ContainsGenericParameters property returns true).

NotSupportedException

type cannot be a TypeBuilder.

-or-

Creation of TypedReference, ArgIterator, Void, and RuntimeArgumentHandle types, or arrays of those types, is not supported.

-or-

The assembly that contains type is a dynamic assembly that was created with Save.

-or-

The constructor that best matches args has varargs arguments.

TargetInvocationException

The constructor being called throws an exception.

MethodAccessException

The caller does not have permission to call this constructor.

Note: In .NET for Windows Store apps or the Portable Class Library, catch the base class exception, MemberAccessException, instead.

MemberAccessException

Cannot create an instance of an abstract class, or this member was invoked with a late-binding mechanism.

InvalidComObjectException

The COM type was not obtained through GetTypeFromProgID or GetTypeFromCLSID.

MissingMethodException

No matching public constructor was found.

Note: In .NET for Windows Store apps or the Portable Class Library, catch the base class exception, MissingMemberException, instead.

COMException

type is a COM object but the class identifier used to obtain the type is invalid, or the identified class is not registered.

TypeLoadException

type is not a valid type.

Examples

The following example calls the CreateInstance(Type, Object[]) method to create a String object. It calls the String.String(Char[], Int32, Int32) constructor to instantiate a string that contains ten elements from a character array starting at the fourteenth position.

using System;

public class Example
{
   public static void Main()
   {
      // Initialize array of characters from a to z.
      char[] chars = new char[26];
      for (int ctr = 0; ctr < 26; ctr++)
         chars[ctr] = (char) (ctr + 0x0061);

      object obj = Activator.CreateInstance(typeof(string),
                                            new object[] { chars, 13, 10 } );
      Console.WriteLine(obj);
   }
}
// The example displays the following output:
//       nopqrstuvw

open System

// Initialize array of characters from a to z.
let chars = [| 'a' .. 'z' |]

let obj = Activator.CreateInstance(typeof<string>, chars[13..22])

printfn $"{obj}"

// The example displays the following output:
//       nopqrstuvw

Module Example
   Public Sub Main()
      ' Initialize array of characters from a to z.
      Dim chars(25) As Char 
      For ctr As Short = 0 To 25
         chars(ctr) = ChrW(ctr + &h0061)
      Next 
      Dim obj As Object = Activator.CreateInstance(GetType(String),
                                                   { chars, 13, 10 })
      Console.WriteLine(obj)                                          
   End Sub
End Module
' The example displays the following output:
'       nopqrstuvw

The following example creates a jagged array whose elements are arguments to be passed to a String constructor. The example then passes each array to the CreateInstance(Type, Object[]) method to invoke the appropriate string constructor.

using System;

public class Example
{
   public static void Main()
   {
      char[] characters = { 'a', 'b', 'c', 'd', 'e', 'f' };
      object[][] arguments = new object[3][] { new object[] { characters },
                                               new object[] { characters, 1, 4 },
                                               new object[] { characters[1], 20 } };

      for (int ctr = 0; ctr <= arguments.GetUpperBound(0); ctr++) {
         object[] args = arguments[ctr];
         object result = Activator.CreateInstance(typeof(string), args);
         Console.WriteLine("{0}: {1}", result.GetType().Name, result);
      }
   }
}
// The example displays the following output:
//    String: abcdef
//    String: bcde
//    String: bbbbbbbbbbbbbbbbbbbb

open System

let chars = [| 'a' .. 'f' |]

let arguments =
    [| chars
       chars[1..4]
       Array.create 20 chars[1] |]

for args in arguments do
    let result =
        Activator.CreateInstance(typeof<string>, args)

    printfn $"{result.GetType().Name}: {result}"

// The example displays the following output:
//    String: abcdef
//    String: bcde
//    String: bbbbbbbbbbbbbbbbbbbb

Module Example
   Public Sub Main()
      Dim characters() As Char = { "a"c, "b"c, "c"c, "d"c, "e"c, "f"c }
      Dim arguments()() As Object = new Object(2)() { New Object() { characters },
                                                      New Object() { characters, 1, 4 },
                                                      New Object() { characters(1), 20 } }

      For ctr As Integer = 0 To arguments.GetUpperBound(0)
         Dim args() As Object = arguments(ctr)
         Dim result As Object = Activator.CreateInstance(GetType(String), args)
         Console.WriteLine("{0}: {1}", result.GetType().Name, result)
      Next
   End Sub
End Module
' The example displays the following output:
'       String: abcdef
'       String: bcde
'       String: bbbbbbbbbbbbbbbbbbbb

Remarks

The constructor to be invoked must be accessible and must provide the most specific match with the specified argument list.

Note

Starting with .NET Framework 2.0, this method can be used to access nonpublic types if the caller has been granted ReflectionPermission with the ReflectionPermissionFlag.RestrictedMemberAccess flag and if the grant set of the assembly that contains the nonpublic types is restricted to the caller's grant set or to a subset thereof. (See Security Considerations for Reflection.) To use this functionality, your application should target .NET Framework 3.5 or later.

CreateInstance(Type, Boolean)

Source:

Activator.RuntimeType.cs

Creates an instance of the specified type using that type's parameterless constructor.

public:
 static System::Object ^ CreateInstance(Type ^ type, bool nonPublic);

public static object? CreateInstance (Type type, bool nonPublic);

static member CreateInstance : Type * bool -> obj

Public Shared Function CreateInstance (type As Type, nonPublic As Boolean) As Object

Parameters

type

Type

The type of object to create.

nonPublic

Boolean

true if a public or nonpublic parameterless constructor can match; false if only a public parameterless constructor can match.

Returns

Object

A reference to the newly created object, or null for Nullable<T> instances.

Exceptions

ArgumentNullException

type is null.

ArgumentException

type is not a RuntimeType.

-or-

type is an open generic type (that is, the ContainsGenericParameters property returns true).

NotSupportedException

type cannot be a TypeBuilder.

-or-

Creation of TypedReference, ArgIterator, Void, and RuntimeArgumentHandle types, or arrays of those types, is not supported.

-or-

The assembly that contains type is a dynamic assembly that was created with Save.

TargetInvocationException

The constructor being called throws an exception.

MethodAccessException

The caller does not have permission to call this constructor.

MemberAccessException

Cannot create an instance of an abstract class, or this member was invoked with a late-binding mechanism.

InvalidComObjectException

The COM type was not obtained through GetTypeFromProgID or GetTypeFromCLSID.

MissingMethodException

No matching public constructor was found.

COMException

type is a COM object but the class identifier used to obtain the type is invalid, or the identified class is not registered.

TypeLoadException

type is not a valid type.

Remarks

Note

Starting with .NET Framework 2.0, this method can be used to access nonpublic types and members if the caller has been granted ReflectionPermission with the ReflectionPermissionFlag.RestrictedMemberAccess flag and if the grant set of the assembly that contains the nonpublic types and members is restricted to the caller's grant set or to a subset thereof. (See Security Considerations for Reflection.) To use this functionality, your application should target .NET Framework 3.5 or later.

CreateInstance(String, String)

Source:

Activator.RuntimeType.cs

Creates an instance of the type whose name is specified, using the named assembly and parameterless constructor.

public:
 static System::Runtime::Remoting::ObjectHandle ^ CreateInstance(System::String ^ assemblyName, System::String ^ typeName);

public static System.Runtime.Remoting.ObjectHandle? CreateInstance (string assemblyName, string typeName);

static member CreateInstance : string * string -> System.Runtime.Remoting.ObjectHandle

Public Shared Function CreateInstance (assemblyName As String, typeName As String) As ObjectHandle

Parameters

assemblyName

String

The name of the assembly where the type named typeName is sought. If assemblyName is null, the executing assembly is searched.

typeName

String

The fully qualified name of the type to create an instance of.

Returns

ObjectHandle

A handle that must be unwrapped to access the newly created object, or null for Nullable<T> instances.

Exceptions

ArgumentNullException

typeName is null.

MissingMethodException

No matching public constructor was found.

TypeLoadException

typeName was not found in assemblyName.

FileNotFoundException

assemblyName was not found.

MethodAccessException

The caller does not have permission to call this constructor.

MemberAccessException

You cannot create an instance of an abstract class, or this member was invoked with a late-binding mechanism.

TargetInvocationException

The constructor, which was invoked through reflection, threw an exception.

InvalidComObjectException

The COM type was not obtained through GetTypeFromProgID or GetTypeFromCLSID.

NotSupportedException

Creation of TypedReference, ArgIterator, Void, and RuntimeArgumentHandle types, or arrays of those types, is not supported.

BadImageFormatException

assemblyName is not a valid assembly.

-or-

The common language runtime (CLR) version 2.0 or later is currently loaded, and assemblyName was compiled for a version of the CLR that is later than the currently loaded version. Note that the .NET Framework versions 2.0, 3.0, and 3.5 all use CLR version 2.0.

FileLoadException

An assembly or module was loaded twice with two different evidences.

-or-

The assembly name or code base is invalid.

Examples

The following example defines a class named Person in an assembly named PersonInfo. Note that the Person class has two constructors, one of which is parameterless.

using System;

public class Person
{
   private string _name;

   public Person()
   { }

   public Person(string name)
   {
      this._name = name;
   }

   public string Name
   { get { return this._name; }
     set { this._name = value; } }

   public override string ToString()
   {
      return this._name;
   }
}

type Person(name) =
    member val Name = name with get, set

    override this.ToString() = this.Name

    new () = Person Unchecked.defaultof<string>

Public Class Person
   Private _name As String
   
   Public Sub New()
   End Sub
   
   Public Sub New(name As String)
      Me._name = name
   End Sub
   
   Public Property Name As String
      Get
         Return Me._name
      End Get
      Set
         Me._name = value
      End Set
   End Property
   
   Public Overrides Function ToString() As String
      Return Me._name
   End Function
End Class

The following example calls the CreateInstance(String, String) method to instantiate the Person class. It requires a reference to PersonInfo.dll to be added to the project. Because the CreateInstance(String, String) method calls the Person class parameterless constructor, the example assigns a value to its Name property.

using System;
using System.Runtime.Remoting;

public class Example
{
   public static void Main()
   {
      ObjectHandle handle = Activator.CreateInstance("PersonInfo", "Person");
      Person p = (Person) handle.Unwrap();
      p.Name = "Samuel";
      Console.WriteLine(p);
   }
}
// The example displays the following output:
//        Samuel

open System

let handle = Activator.CreateInstance("PersonInfo", "Person")
let p = handle.Unwrap() :?> Person
p.Name <- "Samuel"
printfn $"{p}"

// The example displays the following output:
//        Samuel

Imports System.Runtime.Remoting

Module Example
   Public Sub Main()
      Dim handle As ObjectHandle = Activator.CreateInstance("PersonInfo", "Person")
      Dim p As Person = CType(handle.Unwrap(), Person)
      p.Name = "Samuel"
      Console.WriteLine(p)
   End Sub
End Module
' The example displays the following output:
'       Samuel

However, CreateInstance is frequently called to instantiate a type that crosses machine boundaries or that is not known at design time. In this case, you cannot include a reference to the assembly in the project and cannot make early-bound calls to the type's members. To work around this limitation, the following example uses the CreateInstance method along with reflection to assign a value to the Person object's Name property and to display its value.

using System;
using System.Reflection;
using System.Runtime.Remoting;

public class Example
{
   public static void Main()
   {
      ObjectHandle handle = Activator.CreateInstance("PersonInfo", "Person");
      object p = handle.Unwrap();
      Type t = p.GetType();
      PropertyInfo prop = t.GetProperty("Name");
      if (prop != null)
         prop.SetValue(p, "Samuel");

      MethodInfo method = t.GetMethod("ToString");
      object retVal = method.Invoke(p, null);
      if (retVal != null)
         Console.WriteLine(retVal);
   }
}
// The example displays the following output:
//        Samuel

open System

let handle =
    Activator.CreateInstance("PersonInfo", "Person")

let p = handle.Unwrap()
let t = p.GetType()
let prop = t.GetProperty "Name"

if not (isNull prop) then
    prop.SetValue(p, "Samuel")

let method = t.GetMethod "ToString"
let retVal = method.Invoke(p, null)

if not (isNull retVal) then
    printfn $"{retVal}"

// The example displays the following output:
//        Samuel

Imports System.Reflection
Imports System.Runtime.Remoting

Module Example
   Public Sub Main()
      Dim handle As ObjectHandle = Activator.CreateInstance("PersonInfo", "Person")
      Dim p As Object = handle.Unwrap()
      Dim t As Type = p.GetType()
      Dim prop As PropertyInfo = t.GetProperty("Name")
      if Not prop Is Nothing Then
         prop.SetValue(p, "Samuel")
      End If   
      Dim method As MethodInfo = t.GetMethod("ToString")
      Dim retVal As Object = method.Invoke(p, Nothing) 
      If Not retVal Is Nothing Then
         Console.WriteLine(retVal)
      End If
   End Sub
End Module
' The example displays the following output:
'       Samuel

Remarks

Use ObjectHandle.Unwrap to unwrap the return value.

assemblyName can be either of the following:

• The simple name of an assembly, without its path or file extension. For example, you would specify TypeExtensions for an assembly whose path and name are .\bin\TypeExtensions.dll.

• The full name of a signed assembly, which consists of its simple name, version, culture, and public key token; for example, "TypeExtensions, Version=1.0.0.0, Culture=neutral, PublicKeyToken=181869f2f7435b51".

For more information on how the common language runtime identifies and loads assemblies, see How the Runtime Locates Assemblies. For information on using the application configuration file to define assembly locations, see Specifying an Assembly's Location. If assemblyName is found, it is loaded in the default context.

Note

Starting with .NET Framework 2.0, this method can be used to create nonpublic types if the caller has been granted ReflectionPermission with the ReflectionPermissionFlag.RestrictedMemberAccess flag and if the grant set of the assembly that contains the nonpublic types is restricted to the caller's grant set or to a subset thereof. (See Security Considerations for Reflection.) To use this functionality, your application should target .NET Framework 3.5 or later.

CreateInstance(Type)

Source:

Activator.cs

Creates an instance of the specified type using that type's parameterless constructor.

public:
 static System::Object ^ CreateInstance(Type ^ type);

public static object? CreateInstance (Type type);

static member CreateInstance : Type -> obj

Public Shared Function CreateInstance (type As Type) As Object

Parameters

type

Type

The type of object to create.

Returns

Object

A reference to the newly created object, or null for Nullable<T> instances.

Exceptions

ArgumentNullException

type is null.

ArgumentException

type is not a RuntimeType.

-or-

type is an open generic type (that is, the ContainsGenericParameters property returns true).

NotSupportedException

type cannot be a TypeBuilder.

-or-

Creation of TypedReference, ArgIterator, Void, and RuntimeArgumentHandle types, or arrays of those types, is not supported.

-or-

The assembly that contains type is a dynamic assembly that was created with Save.

TargetInvocationException

The constructor being called throws an exception.

MethodAccessException

The caller does not have permission to call this constructor.

Note: In .NET for Windows Store apps or the Portable Class Library, catch the base class exception, MemberAccessException, instead.

MemberAccessException

Cannot create an instance of an abstract class, or this member was invoked with a late-binding mechanism.

InvalidComObjectException

The COM type was not obtained through GetTypeFromProgID or GetTypeFromCLSID.

MissingMethodException

No matching public constructor was found.

Note: In .NET for Windows Store apps or the Portable Class Library, catch the base class exception, MissingMemberException, instead.

COMException

type is a COM object but the class identifier used to obtain the type is invalid, or the identified class is not registered.

TypeLoadException

type is not a valid type.

Examples

The following code example demonstrates how to call the CreateInstance(Type) method. Instances of several different types are created and their default values are displayed.

using namespace System;

ref class DynamicInstanceList
{
private:
    static String^ instanceSpec = "System.EventArgs;System.Random;" +
        "System.Exception;System.Object;System.Version";

public:
    static void Main()
    {
        array<String^>^ instances = instanceSpec->Split(';');
        Array^ instlist = Array::CreateInstance(Object::typeid, instances->Length);
        Object^ item;

        for (int i = 0; i < instances->Length; i++)
        {
            // create the object from the specification string
            Console::WriteLine("Creating instance of: {0}", instances[i]);
            item = Activator::CreateInstance(Type::GetType(instances[i]));
            instlist->SetValue(item, i);
        }
        Console::WriteLine("\nObjects and their default values:\n");
        for each (Object^ o in instlist)
        {
            Console::WriteLine("Type:     {0}\nValue:    {1}\nHashCode: {2}\n",
                o->GetType()->FullName, o->ToString(), o->GetHashCode());
        }
    }
};

int main()
{
    DynamicInstanceList::Main();
}

// This program will display output similar to the following:
//
// Creating instance of: System.EventArgs
// Creating instance of: System.Random
// Creating instance of: System.Exception
// Creating instance of: System.Object
// Creating instance of: System.Version
//
// Objects and their default values:
//
// Type:     System.EventArgs
// Value:    System.EventArgs
// HashCode: 46104728
//
// Type:     System.Random
// Value:    System.Random
// HashCode: 12289376
//
// Type:     System.Exception
// Value:    System.Exception: Exception of type 'System.Exception' was thrown.
// HashCode: 55530882
//
// Type:     System.Object
// Value:    System.Object
// HashCode: 30015890
//
// Type:     System.Version
// Value:    0.0
// HashCode: 1048575

using System;

class DynamicInstanceList
{
    private static string instanceSpec = "System.EventArgs;System.Random;" +
        "System.Exception;System.Object;System.Version";

    public static void Main()
    {
        string[] instances = instanceSpec.Split(';');
        Array instlist = Array.CreateInstance(typeof(object), instances.Length);
        object item;
        for (int i = 0; i < instances.Length; i++)
        {
            // create the object from the specification string
            Console.WriteLine("Creating instance of: {0}", instances[i]);
            item = Activator.CreateInstance(Type.GetType(instances[i]));
            instlist.SetValue(item, i);
        }
        Console.WriteLine("\nObjects and their default values:\n");
        foreach (object o in instlist)
        {
            Console.WriteLine("Type:     {0}\nValue:    {1}\nHashCode: {2}\n",
                o.GetType().FullName, o.ToString(), o.GetHashCode());
        }
    }
}

// This program will display output similar to the following:
//
// Creating instance of: System.EventArgs
// Creating instance of: System.Random
// Creating instance of: System.Exception
// Creating instance of: System.Object
// Creating instance of: System.Version
//
// Objects and their default values:
//
// Type:     System.EventArgs
// Value:    System.EventArgs
// HashCode: 46104728
//
// Type:     System.Random
// Value:    System.Random
// HashCode: 12289376
//
// Type:     System.Exception
// Value:    System.Exception: Exception of type 'System.Exception' was thrown.
// HashCode: 55530882
//
// Type:     System.Object
// Value:    System.Object
// HashCode: 30015890
//
// Type:     System.Version
// Value:    0.0
// HashCode: 1048575

open System

let instanceSpec =
    "System.EventArgs;System.Random;System.Exception;System.Object;System.Version"

let instances = instanceSpec.Split ';'
let instlist = Array.zeroCreate instances.Length
let mutable item = obj ()

for i = 0 to instances.Length - 1 do
    // create the object from the specification string
    printfn $"Creating instance of: {instances.[i]}"
    item <- Activator.CreateInstance(Type.GetType instances.[i])
    instlist.[i] <- item

printfn "\nObjects and their default values:\n"

for o in instlist do
    printfn $"Type:     {o.GetType().FullName}\nValue:    {o}\nHashCode: {o.GetHashCode()}\n"


// This program will display output similar to the following:
//
// Creating instance of: System.EventArgs
// Creating instance of: System.Random
// Creating instance of: System.Exception
// Creating instance of: System.Object
// Creating instance of: System.Version
//
// Objects and their default values:
//
// Type:     System.EventArgs
// Value:    System.EventArgs
// HashCode: 46104728
//
// Type:     System.Random
// Value:    System.Random
// HashCode: 12289376
//
// Type:     System.Exception
// Value:    System.Exception: Exception of type 'System.Exception' was thrown.
// HashCode: 55530882
//
// Type:     System.Object
// Value:    System.Object
// HashCode: 30015890
//
// Type:     System.Version
// Value:    0.0
// HashCode: 1048575

Class DynamicInstanceList
    Private Shared instanceSpec As String = "System.EventArgs;System.Random;" + _
        "System.Exception;System.Object;System.Version"

    Public Shared Sub Main()
        Dim instances() As String = instanceSpec.Split(";")
        Dim instlist As Array = Array.CreateInstance(GetType(Object), instances.Length)
        Dim item As Object

        For i As Integer = 0 To instances.Length -1
            ' create the object from the specification string
            Console.WriteLine("Creating instance of: {0}", instances(i))
            item = Activator.CreateInstance(Type.GetType(instances(i)))
            instlist.SetValue(item, i)
        Next i
        Console.WriteLine(Environment.NewLine + "Objects and their default values:" + Environment.NewLine)
        For Each o As Object In instlist
            Console.WriteLine("Type:     {0}" + Environment.NewLine + "Value:    {1}" + _
                Environment.NewLine + "HashCode: {2}" + Environment.NewLine, _
                o.GetType().FullName, o.ToString(), o.GetHashCode())
        Next o
    End Sub
End Class

' This program will display output similar to the following:
'
' Creating instance of: System.EventArgs
' Creating instance of: System.Random
' Creating instance of: System.Exception
' Creating instance of: System.Object
' Creating instance of: System.Version
'
' Objects and their default values:
'
' Type:     System.EventArgs
' Value:    System.EventArgs
' HashCode: 46104728
'
' Type:     System.Random
' Value:    System.Random
' HashCode: 12289376
'
' Type:     System.Exception
' Value:    System.Exception: Exception of type 'System.Exception' was thrown.
' HashCode: 55530882
'
' Type:     System.Object
' Value:    System.Object
' HashCode: 30015890
'
' Type:     System.Version
' Value:    0.0
' HashCode: 1048575

Remarks

The constructor to be invoked must be accessible.

Note

Starting with .NET Framework 2.0, this method can be used to access nonpublic types if the caller has been granted ReflectionPermission with the ReflectionPermissionFlag.RestrictedMemberAccess flag and if the grant set of the assembly that contains the nonpublic types is restricted to the caller's grant set or to a subset thereof. (See Security Considerations for Reflection.) To use this functionality, your application should target .NET Framework 3.5 or later.

CreateInstance<T>()

Source:

Activator.RuntimeType.cs

Creates an instance of the type designated by the specified generic type parameter, using the parameterless constructor.

public:
generic <typename T>
 static T CreateInstance();

public static T CreateInstance<T> ();

static member CreateInstance : unit -> 'T

Public Shared Function CreateInstance(Of T) () As T

Type Parameters

T

The type to create.

Returns

T

A reference to the newly created object, or null for Nullable<T> instances.

Exceptions

MissingMethodException

Cannot create an instance of an abstract class, or the type that is specified for T does not have a parameterless constructor.

Note: In .NET for Windows Store apps or the Portable Class Library, catch the base class exception, MissingMemberException, instead.

Remarks

The CreateInstance<T>() generic method is used by compilers to implement the instantiation of types specified by type parameters. For example, in the following generic method, the implementation of new T() (gcnew T() in C++) uses the CreateInstance<T>() generic method.

public:
    generic <typename T> where T:gcnew()
    static T Bar()
    {
        return gcnew T();
    }

public static T Factory<T>() where T : new()
{
    return new T();
}

let factory<'T when 'T : (new: unit -> 'T)> =
    new 'T()

Public Shared Function Factory(Of T As New)() As T
    Return New T()
End Function

In general, there is no use for the CreateInstance<T>() generic method in application code, because the type must be known at compile time. If the type is known at compile time, normal instantiation syntax can be used (new operator in C#, New in Visual Basic, gcnew in C++). If the type is not known at compile time, you can call a non-generic overload of CreateInstance.

There are no overloads of the CreateInstance<T>() generic method that take argument lists, because the non-generic overloads of CreateInstance already provide late-bound constructor resolution.