ConstructorBuilder-Klasse
Definiert einen Konstruktor einer dynamischen Klasse und stellt diesen dar.
Namespace: System.Reflection.Emit
Assembly: mscorlib (in mscorlib.dll)
Syntax
'Declaration
<ClassInterfaceAttribute(ClassInterfaceType.None)> _
<ComVisibleAttribute(True)> _
Public NotInheritable Class ConstructorBuilder
Inherits ConstructorInfo
Implements _ConstructorBuilder
'Usage
Dim instance As ConstructorBuilder
[ClassInterfaceAttribute(ClassInterfaceType.None)]
[ComVisibleAttribute(true)]
public sealed class ConstructorBuilder : ConstructorInfo, _ConstructorBuilder
[ClassInterfaceAttribute(ClassInterfaceType::None)]
[ComVisibleAttribute(true)]
public ref class ConstructorBuilder sealed : public ConstructorInfo, _ConstructorBuilder
/** @attribute ClassInterfaceAttribute(ClassInterfaceType.None) */
/** @attribute ComVisibleAttribute(true) */
public final class ConstructorBuilder extends ConstructorInfo implements _ConstructorBuilder
ClassInterfaceAttribute(ClassInterfaceType.None)
ComVisibleAttribute(true)
public final class ConstructorBuilder extends ConstructorInfo implements _ConstructorBuilder
Hinweise
Hinweis
Das auf diese Klasse angewendete HostProtectionAttribute-Attribut besitzt den Resources-Eigenschaftenwert MayLeakOnAbort. Das HostProtectionAttribute hat keine Auswirkungen auf Desktopanwendungen (die normalerweise durch Doppelklicken auf ein Symbol, Eingeben eines Befehls oder eines URL in einem Browser gestartet werden). Weitere Informationen finden Sie unter der HostProtectionAttribute-Klasse oder unter SQL Server-Programmierung und Hostschutzattribute.
ConstructorBuilder wird für die vollständige Beschreibung eines Konstruktors in MSIL (Microsoft Intermediate Language) verwendet, in der auch Name, Attribute, Signatur und Konstruktorrumpf verwendet. Er wird zusammen mit der TypeBuilder-Klasse zum Erstellen von Klassen zur Laufzeit verwendet. Über einen Aufruf von DefineConstructor wird eine Instanz von ConstructorBuilder abgerufen.
Im folgenden Codebeispiel wird die kontextabhängige Verwendung eines ConstructorBuilder veranschaulicht.
Imports System
Imports System.Threading
Imports System.Reflection
Imports System.Reflection.Emit
_
Class TestCtorBuilder
Public Shared Function DynamicPointTypeGen() As Type
Dim pointType As Type = Nothing
Dim ctorParams() As Type = {GetType(Integer), GetType(Integer), GetType(Integer)}
Dim myDomain As AppDomain = Thread.GetDomain()
Dim myAsmName As New AssemblyName()
myAsmName.Name = "MyDynamicAssembly"
Dim myAsmBuilder As AssemblyBuilder = myDomain.DefineDynamicAssembly(myAsmName, AssemblyBuilderAccess.RunAndSave)
Dim pointModule As ModuleBuilder = myAsmBuilder.DefineDynamicModule("PointModule", "Point.dll")
Dim pointTypeBld As TypeBuilder = pointModule.DefineType("Point", TypeAttributes.Public)
Dim xField As FieldBuilder = pointTypeBld.DefineField("x", GetType(Integer), FieldAttributes.Public)
Dim yField As FieldBuilder = pointTypeBld.DefineField("y", GetType(Integer), FieldAttributes.Public)
Dim zField As FieldBuilder = pointTypeBld.DefineField("z", GetType(Integer), FieldAttributes.Public)
Dim objType As Type = Type.GetType("System.Object")
Dim objCtor As ConstructorInfo = objType.GetConstructor(New Type() {})
Dim pointCtor As ConstructorBuilder = pointTypeBld.DefineConstructor(MethodAttributes.Public, CallingConventions.Standard, ctorParams)
Dim ctorIL As ILGenerator = pointCtor.GetILGenerator()
' NOTE: ldarg.0 holds the "this" reference - ldarg.1, ldarg.2, and ldarg.3
' hold the actual passed parameters. ldarg.0 is used by instance methods
' to hold a reference to the current calling object instance. Static methods
' do not use arg.0, since they are not instantiated and hence no reference
' is needed to distinguish them.
ctorIL.Emit(OpCodes.Ldarg_0)
' Here, we wish to create an instance of System.Object by invoking its
' constructor, as specified above.
ctorIL.Emit(OpCodes.Call, objCtor)
' Now, we'll load the current instance ref in arg 0, along
' with the value of parameter "x" stored in arg 1, into stfld.
ctorIL.Emit(OpCodes.Ldarg_0)
ctorIL.Emit(OpCodes.Ldarg_1)
ctorIL.Emit(OpCodes.Stfld, xField)
' Now, we store arg 2 "y" in the current instance with stfld.
ctorIL.Emit(OpCodes.Ldarg_0)
ctorIL.Emit(OpCodes.Ldarg_2)
ctorIL.Emit(OpCodes.Stfld, yField)
' Last of all, arg 3 "z" gets stored in the current instance.
ctorIL.Emit(OpCodes.Ldarg_0)
ctorIL.Emit(OpCodes.Ldarg_3)
ctorIL.Emit(OpCodes.Stfld, zField)
' Our work complete, we return.
ctorIL.Emit(OpCodes.Ret)
' Now, let's create three very simple methods so we can see our fields.
Dim mthdNames() As String = {"GetX", "GetY", "GetZ"}
Dim mthdName As String
For Each mthdName In mthdNames
Dim getFieldMthd As MethodBuilder = pointTypeBld.DefineMethod(mthdName, MethodAttributes.Public, GetType(Integer), Nothing)
Dim mthdIL As ILGenerator = getFieldMthd.GetILGenerator()
mthdIL.Emit(OpCodes.Ldarg_0)
Select Case mthdName
Case "GetX"
mthdIL.Emit(OpCodes.Ldfld, xField)
Case "GetY"
mthdIL.Emit(OpCodes.Ldfld, yField)
Case "GetZ"
mthdIL.Emit(OpCodes.Ldfld, zField)
End Select
mthdIL.Emit(OpCodes.Ret)
Next mthdName
' Finally, we create the type.
pointType = pointTypeBld.CreateType()
' Let's save it, just for posterity.
myAsmBuilder.Save("Point.dll")
Return pointType
End Function 'DynamicPointTypeGen
Public Shared Sub Main()
Dim myDynamicType As Type = Nothing
Dim aPoint As Object = Nothing
Dim aPtypes() As Type = {GetType(Integer), GetType(Integer), GetType(Integer)}
Dim aPargs() As Object = {4, 5, 6}
' Call the method to build our dynamic class.
myDynamicType = DynamicPointTypeGen()
Console.WriteLine("Some information about my new Type '{0}':", myDynamicType.FullName)
Console.WriteLine("Assembly: '{0}'", myDynamicType.Assembly)
Console.WriteLine("Attributes: '{0}'", myDynamicType.Attributes)
Console.WriteLine("Module: '{0}'", myDynamicType.Module)
Console.WriteLine("Members: ")
Dim member As MemberInfo
For Each member In myDynamicType.GetMembers()
Console.WriteLine("-- {0} {1};", member.MemberType, member.Name)
Next member
Console.WriteLine("---")
' Let's take a look at the constructor we created.
Dim myDTctor As ConstructorInfo = myDynamicType.GetConstructor(aPtypes)
Console.WriteLine("Constructor: {0};", myDTctor.ToString())
Console.WriteLine("---")
' Now, we get to use our dynamically-created class by invoking the constructor.
aPoint = myDTctor.Invoke(aPargs)
Console.WriteLine("aPoint is type {0}.", aPoint.GetType())
' Finally, let's reflect on the instance of our new type - aPoint - and
' make sure everything proceeded according to plan.
Console.WriteLine("aPoint.x = {0}", myDynamicType.InvokeMember("GetX", BindingFlags.InvokeMethod, Nothing, aPoint, New Object() {}))
Console.WriteLine("aPoint.y = {0}", myDynamicType.InvokeMember("GetY", BindingFlags.InvokeMethod, Nothing, aPoint, New Object() {}))
Console.WriteLine("aPoint.z = {0}", myDynamicType.InvokeMember("GetZ", BindingFlags.InvokeMethod, Nothing, aPoint, New Object() {}))
End Sub 'Main
End Class 'TestCtorBuilder
' +++ OUTPUT +++
' Some information about my new Type 'Point':
' Assembly: 'MyDynamicAssembly, Version=0.0.0.0'
' Attributes: 'AutoLayout, AnsiClass, NotPublic, Public'
' Module: 'PointModule'
' Members:
' -- Field x;
' -- Field y;
' -- Field z;
' -- Method GetHashCode;
' -- Method Equals;
' -- Method ToString;
' -- Method GetType;
' -- Constructor .ctor;
' ---
' Constructor: Void .ctor(Int32, Int32, Int32);
' ---
' aPoint is type Point.
' aPoint.x = 4
' aPoint.y = 5
' aPoint.z = 6
using System;
using System.Threading;
using System.Reflection;
using System.Reflection.Emit;
class TestCtorBuilder {
public static Type DynamicPointTypeGen() {
Type pointType = null;
Type[] ctorParams = new Type[] {typeof(int),
typeof(int),
typeof(int)};
AppDomain myDomain = Thread.GetDomain();
AssemblyName myAsmName = new AssemblyName();
myAsmName.Name = "MyDynamicAssembly";
AssemblyBuilder myAsmBuilder = myDomain.DefineDynamicAssembly(
myAsmName,
AssemblyBuilderAccess.RunAndSave);
ModuleBuilder pointModule = myAsmBuilder.DefineDynamicModule("PointModule",
"Point.dll");
TypeBuilder pointTypeBld = pointModule.DefineType("Point",
TypeAttributes.Public);
FieldBuilder xField = pointTypeBld.DefineField("x", typeof(int),
FieldAttributes.Public);
FieldBuilder yField = pointTypeBld.DefineField("y", typeof(int),
FieldAttributes.Public);
FieldBuilder zField = pointTypeBld.DefineField("z", typeof(int),
FieldAttributes.Public);
Type objType = Type.GetType("System.Object");
ConstructorInfo objCtor = objType.GetConstructor(new Type[0]);
ConstructorBuilder pointCtor = pointTypeBld.DefineConstructor(
MethodAttributes.Public,
CallingConventions.Standard,
ctorParams);
ILGenerator ctorIL = pointCtor.GetILGenerator();
// NOTE: ldarg.0 holds the "this" reference - ldarg.1, ldarg.2, and ldarg.3
// hold the actual passed parameters. ldarg.0 is used by instance methods
// to hold a reference to the current calling object instance. Static methods
// do not use arg.0, since they are not instantiated and hence no reference
// is needed to distinguish them.
ctorIL.Emit(OpCodes.Ldarg_0);
// Here, we wish to create an instance of System.Object by invoking its
// constructor, as specified above.
ctorIL.Emit(OpCodes.Call, objCtor);
// Now, we'll load the current instance ref in arg 0, along
// with the value of parameter "x" stored in arg 1, into stfld.
ctorIL.Emit(OpCodes.Ldarg_0);
ctorIL.Emit(OpCodes.Ldarg_1);
ctorIL.Emit(OpCodes.Stfld, xField);
// Now, we store arg 2 "y" in the current instance with stfld.
ctorIL.Emit(OpCodes.Ldarg_0);
ctorIL.Emit(OpCodes.Ldarg_2);
ctorIL.Emit(OpCodes.Stfld, yField);
// Last of all, arg 3 "z" gets stored in the current instance.
ctorIL.Emit(OpCodes.Ldarg_0);
ctorIL.Emit(OpCodes.Ldarg_3);
ctorIL.Emit(OpCodes.Stfld, zField);
// Our work complete, we return.
ctorIL.Emit(OpCodes.Ret);
// Now, let's create three very simple methods so we can see our fields.
string[] mthdNames = new string[] {"GetX", "GetY", "GetZ"};
foreach (string mthdName in mthdNames) {
MethodBuilder getFieldMthd = pointTypeBld.DefineMethod(
mthdName,
MethodAttributes.Public,
typeof(int),
null);
ILGenerator mthdIL = getFieldMthd.GetILGenerator();
mthdIL.Emit(OpCodes.Ldarg_0);
switch (mthdName) {
case "GetX": mthdIL.Emit(OpCodes.Ldfld, xField);
break;
case "GetY": mthdIL.Emit(OpCodes.Ldfld, yField);
break;
case "GetZ": mthdIL.Emit(OpCodes.Ldfld, zField);
break;
}
mthdIL.Emit(OpCodes.Ret);
}
// Finally, we create the type.
pointType = pointTypeBld.CreateType();
// Let's save it, just for posterity.
myAsmBuilder.Save("Point.dll");
return pointType;
}
public static void Main() {
Type myDynamicType = null;
object aPoint = null;
Type[] aPtypes = new Type[] {typeof(int), typeof(int), typeof(int)};
object[] aPargs = new object[] {4, 5, 6};
// Call the method to build our dynamic class.
myDynamicType = DynamicPointTypeGen();
Console.WriteLine("Some information about my new Type '{0}':",
myDynamicType.FullName);
Console.WriteLine("Assembly: '{0}'", myDynamicType.Assembly);
Console.WriteLine("Attributes: '{0}'", myDynamicType.Attributes);
Console.WriteLine("Module: '{0}'", myDynamicType.Module);
Console.WriteLine("Members: ");
foreach (MemberInfo member in myDynamicType.GetMembers()) {
Console.WriteLine("-- {0} {1};", member.MemberType, member.Name);
}
Console.WriteLine("---");
// Let's take a look at the constructor we created.
ConstructorInfo myDTctor = myDynamicType.GetConstructor(aPtypes);
Console.WriteLine("Constructor: {0};", myDTctor.ToString());
Console.WriteLine("---");
// Now, we get to use our dynamically-created class by invoking the constructor.
aPoint = myDTctor.Invoke(aPargs);
Console.WriteLine("aPoint is type {0}.", aPoint.GetType());
// Finally, let's reflect on the instance of our new type - aPoint - and
// make sure everything proceeded according to plan.
Console.WriteLine("aPoint.x = {0}",
myDynamicType.InvokeMember("GetX",
BindingFlags.InvokeMethod,
null,
aPoint,
new object[0]));
Console.WriteLine("aPoint.y = {0}",
myDynamicType.InvokeMember("GetY",
BindingFlags.InvokeMethod,
null,
aPoint,
new object[0]));
Console.WriteLine("aPoint.z = {0}",
myDynamicType.InvokeMember("GetZ",
BindingFlags.InvokeMethod,
null,
aPoint,
new object[0]));
// +++ OUTPUT +++
// Some information about my new Type 'Point':
// Assembly: 'MyDynamicAssembly, Version=0.0.0.0'
// Attributes: 'AutoLayout, AnsiClass, NotPublic, Public'
// Module: 'PointModule'
// Members:
// -- Field x;
// -- Field y;
// -- Field z;
// -- Method GetHashCode;
// -- Method Equals;
// -- Method ToString;
// -- Method GetType;
// -- Constructor .ctor;
// ---
// Constructor: Void .ctor(Int32, Int32, Int32);
// ---
// aPoint is type Point.
// aPoint.x = 4
// aPoint.y = 5
// aPoint.z = 6
}
}
using namespace System;
using namespace System::Threading;
using namespace System::Reflection;
using namespace System::Reflection::Emit;
Type^ DynamicPointTypeGen()
{
Type^ pointType = nullptr;
array<Type^>^temp0 = {int::typeid,int::typeid,int::typeid};
array<Type^>^ctorParams = temp0;
AppDomain^ myDomain = Thread::GetDomain();
AssemblyName^ myAsmName = gcnew AssemblyName;
myAsmName->Name = "MyDynamicAssembly";
AssemblyBuilder^ myAsmBuilder = myDomain->DefineDynamicAssembly( myAsmName, AssemblyBuilderAccess::RunAndSave );
ModuleBuilder^ pointModule = myAsmBuilder->DefineDynamicModule( "PointModule", "Point.dll" );
TypeBuilder^ pointTypeBld = pointModule->DefineType( "Point", TypeAttributes::Public );
FieldBuilder^ xField = pointTypeBld->DefineField( "x", int::typeid, FieldAttributes::Public );
FieldBuilder^ yField = pointTypeBld->DefineField( "y", int::typeid, FieldAttributes::Public );
FieldBuilder^ zField = pointTypeBld->DefineField( "z", int::typeid, FieldAttributes::Public );
Type^ objType = Type::GetType( "System.Object" );
ConstructorInfo^ objCtor = objType->GetConstructor( gcnew array<Type^>(0) );
ConstructorBuilder^ pointCtor = pointTypeBld->DefineConstructor( MethodAttributes::Public, CallingConventions::Standard, ctorParams );
ILGenerator^ ctorIL = pointCtor->GetILGenerator();
// NOTE: ldarg.0 holds the "this" reference - ldarg.1, ldarg.2, and ldarg.3
// hold the actual passed parameters. ldarg.0 is used by instance methods
// to hold a reference to the current calling bject instance. Static methods
// do not use arg.0, since they are not instantiated and hence no reference
// is needed to distinguish them.
ctorIL->Emit( OpCodes::Ldarg_0 );
// Here, we wish to create an instance of System::Object by invoking its
// constructor, as specified above.
ctorIL->Emit( OpCodes::Call, objCtor );
// Now, we'll load the current instance in arg 0, along
// with the value of parameter "x" stored in arg 1, into stfld.
ctorIL->Emit( OpCodes::Ldarg_0 );
ctorIL->Emit( OpCodes::Ldarg_1 );
ctorIL->Emit( OpCodes::Stfld, xField );
// Now, we store arg 2 "y" in the current instance with stfld.
ctorIL->Emit( OpCodes::Ldarg_0 );
ctorIL->Emit( OpCodes::Ldarg_2 );
ctorIL->Emit( OpCodes::Stfld, yField );
// Last of all, arg 3 "z" gets stored in the current instance.
ctorIL->Emit( OpCodes::Ldarg_0 );
ctorIL->Emit( OpCodes::Ldarg_3 );
ctorIL->Emit( OpCodes::Stfld, zField );
// Our work complete, we return.
ctorIL->Emit( OpCodes::Ret );
// Now, let's create three very simple methods so we can see our fields.
array<String^>^temp1 = {"GetX","GetY","GetZ"};
array<String^>^mthdNames = temp1;
System::Collections::IEnumerator^ myEnum = mthdNames->GetEnumerator();
while ( myEnum->MoveNext() )
{
String^ mthdName = safe_cast<String^>(myEnum->Current);
MethodBuilder^ getFieldMthd = pointTypeBld->DefineMethod( mthdName, MethodAttributes::Public, int::typeid, nullptr );
ILGenerator^ mthdIL = getFieldMthd->GetILGenerator();
mthdIL->Emit( OpCodes::Ldarg_0 );
if ( mthdName->Equals( "GetX" ) )
mthdIL->Emit( OpCodes::Ldfld, xField );
else
if ( mthdName->Equals( "GetY" ) )
mthdIL->Emit( OpCodes::Ldfld, yField );
else
if ( mthdName->Equals( "GetZ" ) )
mthdIL->Emit( OpCodes::Ldfld, zField );
mthdIL->Emit( OpCodes::Ret );
}
pointType = pointTypeBld->CreateType();
// Let's save it, just for posterity.
myAsmBuilder->Save( "Point.dll" );
return pointType;
}
int main()
{
Type^ myDynamicType = nullptr;
Object^ aPoint = nullptr;
array<Type^>^temp2 = {int::typeid,int::typeid,int::typeid};
array<Type^>^aPtypes = temp2;
array<Object^>^temp3 = {4,5,6};
array<Object^>^aPargs = temp3;
// Call the method to build our dynamic class.
myDynamicType = DynamicPointTypeGen();
Console::WriteLine( "Some information about my new Type '{0}':", myDynamicType->FullName );
Console::WriteLine( "Assembly: '{0}'", myDynamicType->Assembly );
Console::WriteLine( "Attributes: '{0}'", myDynamicType->Attributes );
Console::WriteLine( "Module: '{0}'", myDynamicType->Module );
Console::WriteLine( "Members: " );
System::Collections::IEnumerator^ myEnum = myDynamicType->GetMembers()->GetEnumerator();
while ( myEnum->MoveNext() )
{
MemberInfo^ member = safe_cast<MemberInfo^>(myEnum->Current);
Console::WriteLine( "-- {0} {1};", member->MemberType, member->Name );
}
Console::WriteLine( "---" );
// Let's take a look at the constructor we created.
ConstructorInfo^ myDTctor = myDynamicType->GetConstructor( aPtypes );
Console::WriteLine( "Constructor: {0};", myDTctor );
Console::WriteLine( "---" );
// Now, we get to use our dynamically-created class by invoking the constructor.
aPoint = myDTctor->Invoke( aPargs );
Console::WriteLine( "aPoint is type {0}.", aPoint->GetType() );
// Finally, let's reflect on the instance of our new type - aPoint - and
// make sure everything proceeded according to plan.
Console::WriteLine( "aPoint.x = {0}", myDynamicType->InvokeMember( "GetX", BindingFlags::InvokeMethod, nullptr, aPoint, gcnew array<Object^>(0) ) );
Console::WriteLine( "aPoint.y = {0}", myDynamicType->InvokeMember( "GetY", BindingFlags::InvokeMethod, nullptr, aPoint, gcnew array<Object^>(0) ) );
Console::WriteLine( "aPoint.z = {0}", myDynamicType->InvokeMember( "GetZ", BindingFlags::InvokeMethod, nullptr, aPoint, gcnew array<Object^>(0) ) );
// +++ OUTPUT +++
// Some information about my new Type 'Point':
// Assembly: 'MyDynamicAssembly, Version=0.0.0.0'
// Attributes: 'AutoLayout, AnsiClass, NotPublic, Public'
// Module: 'PointModule'
// Members:
// -- Field x;
// -- Field y;
// -- Field z;
// -- Method GetHashCode;
// -- Method Equals;
// -- Method ToString;
// -- Method GetType;
// -- Constructor .ctor;
// ---
// Constructor: Void .ctor(Int32, Int32, Int32);
// ---
// aPoint is type Point.
// aPoint.x = 4
// aPoint.y = 5
// aPoint.z = 6
}
Vererbungshierarchie
System.Object
System.Reflection.MemberInfo
System.Reflection.MethodBase
System.Reflection.ConstructorInfo
System.Reflection.Emit.ConstructorBuilder
Threadsicherheit
Alle öffentlichen statischen (Shared in Visual Basic) Member dieses Typs sind threadsicher. Bei Instanzmembern ist die Threadsicherheit nicht gewährleistet.
Plattformen
Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
.NET Framework unterstützt nicht alle Versionen sämtlicher Plattformen. Eine Liste der unterstützten Versionen finden Sie unter Systemanforderungen.
Versionsinformationen
.NET Framework
Unterstützt in: 2.0, 1.1, 1.0