ConstructorInfo Class
Microsoft Silverlight will reach end of support after October 2021. Learn more.
Discovers the attributes of a class constructor and provides access to constructor metadata.
Inheritance Hierarchy
System.Object
System.Reflection.MemberInfo
System.Reflection.MethodBase
System.Reflection.ConstructorInfo
System.Reflection.Emit.ConstructorBuilder
Namespace: System.Reflection
Assembly: mscorlib (in mscorlib.dll)
Syntax
'Declaration
<ComVisibleAttribute(True)> _
<ClassInterfaceAttribute(ClassInterfaceType.None)> _
Public MustInherit Class ConstructorInfo _
Inherits MethodBase
[ComVisibleAttribute(true)]
[ClassInterfaceAttribute(ClassInterfaceType.None)]
public abstract class ConstructorInfo : MethodBase
The ConstructorInfo type exposes the following members.
Constructors
| Name | Description | |
|---|---|---|
.gif "Protected method") |
ConstructorInfo | Initializes a new instance of the ConstructorInfo class. |
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Properties
| Name | Description | |
|---|---|---|
.gif "Public property") .gif "Supported by Silverlight for Windows Phone") .gif "Supported by Xbox 360") |
Attributes | Gets the attributes associated with this method. (Inherited from MethodBase.) |
|
CallingConvention | Gets a value that indicates the calling conventions for this method. (Inherited from MethodBase.) |
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ContainsGenericParameters | Gets a value that indicates whether the generic method contains unassigned generic type parameters. (Inherited from MethodBase.) |
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DeclaringType | Gets the class that declares this member. (Inherited from MemberInfo.) |
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IsAbstract | Gets a value that indicates whether the method is abstract (MustInherit in Visual Basic). (Inherited from MethodBase.) |
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IsAssembly | Gets a value that indicates whether the potential visibility of this method or constructor is described by MethodAttributes.Assembly; that is, the method or constructor is visible at most to other types in the same assembly, and is not visible to derived types outside the assembly. (Inherited from MethodBase.) |
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IsConstructor | Gets a value that indicates whether the method is a constructor. (Inherited from MethodBase.) |
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IsFamily | Gets a value that indicates whether the visibility of this method or constructor is described by MethodAttributes.Family; that is, the method or constructor is visible only within its class and derived classes. (Inherited from MethodBase.) |
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IsFamilyAndAssembly | Gets a value that indicates whether the visibility of this method or constructor is described by MethodAttributes.FamANDAssem; that is, the method or constructor can be called by derived classes, but only if they are in the same assembly. (Inherited from MethodBase.) |
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IsFamilyOrAssembly | Gets a value that indicates whether the potential visibility of this method or constructor is described by MethodAttributes.FamORAssem; that is, the method or constructor can be called by derived classes wherever they are, and by classes in the same assembly. (Inherited from MethodBase.) |
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IsFinal | Gets a value that indicates whether this method is final (NotOverridable in Visual Basic). (Inherited from MethodBase.) |
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IsGenericMethod | Gets a value that indicates whether the method is generic. (Inherited from MethodBase.) |
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IsGenericMethodDefinition | Gets a value that indicates whether the method is a generic method definition. (Inherited from MethodBase.) |
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IsHideBySig | Gets a value that indicates whether only a member of the same kind with exactly the same signature is hidden in the derived class. (Inherited from MethodBase.) |
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IsPrivate | Gets a value that indicates whether this member is private. (Inherited from MethodBase.) |
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IsPublic | Gets a value that indicates whether this is a public method. (Inherited from MethodBase.) |
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IsSpecialName | Gets a value that indicates whether this method has a special name. (Inherited from MethodBase.) |
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IsStatic | Gets a value that indicates whether the method is static (Shared in Visual Basic). (Inherited from MethodBase.) |
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IsVirtual | Gets a value that indicates whether the method is virtual (Overridable in Visual Basic). (Inherited from MethodBase.) |
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MemberType | Gets a MemberTypes value indicating that this member is a constructor. (Overrides MemberInfo.MemberType.) |
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MetadataToken | Gets a value that identifies a metadata element. (Inherited from MemberInfo.) |
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MethodHandle | Gets a handle to the internal metadata representation of a method. (Inherited from MethodBase.) |
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Module | Gets the module in which the type that declares the member represented by the current MemberInfo is defined. (Inherited from MemberInfo.) |
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Name | Gets the name of the current member. (Inherited from MemberInfo.) |
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ReflectedType | Gets the class object that was used to obtain this instance of MemberInfo. (Inherited from MemberInfo.) |
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Methods
| Name | Description | |
|---|---|---|
.gif "Public method") |
Equals(Object) | Determines whether the specified Object is equal to the current Object. (Inherited from Object.) |
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Finalize | Allows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.) |
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GetCustomAttributes(Boolean) | When overridden in a derived class, returns an array of all custom attributes applied to this member. (Inherited from MemberInfo.) |
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GetCustomAttributes(Type, Boolean) | When overridden in a derived class, returns an array of custom attributes applied to this member and identified by Type. (Inherited from MemberInfo.) |
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GetGenericArguments | Returns an array of Type objects that represent the type arguments of a generic method or the type parameters of a generic method definition. (Inherited from MethodBase.) |
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GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
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GetMethodImplementationFlags | When overridden in a derived class, returns the MethodImplAttributes flags. (Inherited from MethodBase.) |
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GetParameters | When overridden in a derived class, gets the parameters of this method or constructor. (Inherited from MethodBase.) |
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GetType | Gets the Type of the current instance. (Inherited from Object.) |
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Invoke(array<Object[]) | Invokes the current constructor with the specified arguments. |
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Invoke(Object, array<Object[]) | Invokes the method or constructor represented by the current instance, using the specified parameters. (Inherited from MethodBase.) |
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Invoke(BindingFlags, Binder, array<Object[], CultureInfo) | When implemented in a derived class, invokes the current constructor with the specified arguments, using the specified binder and culture to validate the argument types. |
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Invoke(Object, BindingFlags, Binder, array<Object[], CultureInfo) | When overridden in a derived class, invokes the reflected method or constructor with the given parameters. (Inherited from MethodBase.) |
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IsDefined | When overridden in a derived class, indicates whether one or more attributes of the specified type or of its derived types is applied to this member. (Inherited from MemberInfo.) |
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MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
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ToString | Returns a string that represents the current object. (Inherited from Object.) |
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Fields
| Name | Description | |
|---|---|---|
.gif "Public field") .gif "Static member") |
ConstructorName | Represents the name of the class constructor method as it is stored in metadata. This name is always ".ctor". This field is read-only. |
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TypeConstructorName | Represents the name of the type constructor method as it is stored in metadata. This name is always ".cctor". This property is read-only. |
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Remarks
In Silverlight, you cannot derive from this type.
ConstructorInfo is used to discover the attributes of a constructor and to invoke a constructor. Objects are created by calling Invoke on a ConstructorInfo returned by either the GetConstructors or GetConstructor method of a Type object.
.gif "Note") Note: |
|---|
ConstructorInfo inherits several members from MethodBase, such as IsGenericMethod, that can be used to examine generic methods. Constructors cannot be generic, so these members return false or nulla null reference (Nothing in Visual Basic). |
Platform Notes
.png "Silverlight for Windows Phone"){kind=icon}
Silverlight for Windows Phone
If you call a static constructor using reflection, the application throws ArgumentException instead of MethodAccessException.
Examples
The following example uses ConstructorInfo with GetConstructor and BindingFlags to find the constructors that match the specified search criteria.
| Note: |
|---|
To run this example, see Building Examples That Use a Demo Method and a TextBlock Control. |
Public Class Example
Public Sub New(ByVal i As Integer)
End Sub
Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
Dim myType As Type = GetType(Example)
Dim parameters() As Type = { GetType(Int32) }
' Get the public instance constructor that takes an integer parameter.
Dim ctor As ConstructorInfo = myType.GetConstructor( _
BindingFlags.Instance Or BindingFlags.Public, _
Type.DefaultBinder, _
parameters, _
Nothing)
If ctor Is Nothing Then
outputBlock.Text &= _
"There is no public instance constructor of MyClass " & _
"that takes an integer as a parameter." & vbCrLf
Else
outputBlock.Text &= _
"The public constructor of MyClass that takes an integer " & _
"as a parameter is: " & vbCrLf
outputBlock.Text &= ctor.ToString() & vbCrLf
End If
End Sub
End Class
' This example produces the following output:
'
'The public constructor of MyClass that takes an integer as a parameter is:
'Void .ctor(Int32)
using System;
using System.Reflection;
using System.Security;
public class Example
{
public Example(int i) { }
public static void Demo(System.Windows.Controls.TextBlock outputBlock)
{
Type myType = typeof(Example);
Type[] parameters = { typeof(int) };
// Get the constructor that takes an integer as a parameter.
ConstructorInfo ctor = myType.GetConstructor(
BindingFlags.Instance | BindingFlags.Public,
Type.DefaultBinder,
parameters,
null);
if (ctor == null)
{
outputBlock.Text +=
"There is no public constructor of MyClass that takes an integer as a parameter.\n";
}
else
{
outputBlock.Text +=
"The public constructor of MyClass that takes an integer as a parameter is:\n";
outputBlock.Text += ctor.ToString() + "\n";
}
}
}
/* This example produces the following output:
The public constructor of MyClass that takes an integer as a parameter is:
Void .ctor(Int32)
*/
Version Information
Silverlight
Supported in: 5, 4, 3
Silverlight for Windows Phone
Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0
XNA Framework
Supported in: Xbox 360, Windows Phone OS 7.0
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.
Thread Safety
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.