新しいラベルを宣言します。
Public Overridable Function DefineLabel() As Label
[C#]
public virtual Label DefineLabel();
[C++]
public: virtual Label DefineLabel();
[JScript]
public function DefineLabel() : Label;
戻り値
分岐のトークンとして使用できる新しいラベルを返します。
解説
ストリーム内でラベルの位置を設定するには、 MarkLabel を呼び出す必要があります。
これは単なるトークンで、ストリーム内の特定の位置をまだ表していません。
使用例
[Visual Basic, C#, C++] DefineLabel メソッドの実際の使用方法については、次のコード例を参照してください。
Imports System
Imports System.Threading
Imports System.Reflection
Imports System.Reflection.Emit
_
Class ILLabelDemo
Public Shared Function BuildAdderType() As Type
Dim myDomain As AppDomain = Thread.GetDomain()
Dim myAsmName As New AssemblyName()
myAsmName.Name = "AdderExceptionAsm"
Dim myAsmBldr As AssemblyBuilder = myDomain.DefineDynamicAssembly(myAsmName, _
AssemblyBuilderAccess.Run)
Dim myModBldr As ModuleBuilder = myAsmBldr.DefineDynamicModule("AdderExceptionMod")
Dim myTypeBldr As TypeBuilder = myModBldr.DefineType("Adder")
Dim adderParams() As Type = {GetType(Integer), GetType(Integer)}
' This method will add two numbers which are 100 or less. If either of the
' passed integer vales are greater than 100, it will return the value of -1.
Dim adderBldr As MethodBuilder = myTypeBldr.DefineMethod("DoAdd", _
MethodAttributes.Public Or MethodAttributes.Static, _
GetType(Integer), adderParams)
Dim adderIL As ILGenerator = adderBldr.GetILGenerator()
' In order to successfully branch, we need to create labels
' representing the offset IL instruction block to branch to.
' These labels, when the MarkLabel(Label) method is invoked,
' will specify the IL instruction to branch to.
Dim failed As Label = adderIL.DefineLabel()
Dim endOfMthd As Label = adderIL.DefineLabel()
' First, load argument 0 and the integer value of "100" onto the
' stack. If arg0 > 100, branch to the label "failed", which is marked
' as the address of the block that loads -1 onto the stack, bypassing
' the addition.
adderIL.Emit(OpCodes.Ldarg_0)
adderIL.Emit(OpCodes.Ldc_I4_S, 100)
adderIL.Emit(OpCodes.Bgt_S, failed)
' Now, check to see if argument 1 was greater than 100. If it was,
' branch to "failed." Otherwise, fall through and perform the addition,
' branching unconditionally to the instruction at the label "endOfMthd".
adderIL.Emit(OpCodes.Ldarg_1)
adderIL.Emit(OpCodes.Ldc_I4_S, 100)
adderIL.Emit(OpCodes.Bgt_S, failed)
adderIL.Emit(OpCodes.Ldarg_0)
adderIL.Emit(OpCodes.Ldarg_1)
adderIL.Emit(OpCodes.Add_Ovf_Un)
adderIL.Emit(OpCodes.Br_S, endOfMthd)
' If this label is branched to (the failure case), load -1 onto the stack
' and fall through to the return opcode.
adderIL.MarkLabel(failed)
adderIL.Emit(OpCodes.Ldc_I4_M1)
' The end of the method. If both values were less than 100, the
' correct result will return. If one of the arguments was greater
' than 100, the result will be -1.
adderIL.MarkLabel(endOfMthd)
adderIL.Emit(OpCodes.Ret)
Return myTypeBldr.CreateType()
End Function 'BuildAdderType
Public Shared Sub Main()
Dim adderType As Type = BuildAdderType()
Dim addIns As Object = Activator.CreateInstance(adderType)
Dim addParams(1) As Object
Console.Write("Enter an integer value: ")
addParams(0) = CType(Convert.ToInt32(Console.ReadLine()), Object)
Console.Write("Enter another integer value: ")
addParams(1) = CType(Convert.ToInt32(Console.ReadLine()), Object)
Console.WriteLine("---")
Dim adderResult As Integer = CInt(adderType.InvokeMember("DoAdd", _
BindingFlags.InvokeMethod, Nothing, _
addIns, addParams))
If adderResult <> - 1 Then
Console.WriteLine("{0} + {1} = {2}", addParams(0), addParams(1), adderResult)
Else
Console.WriteLine("One of the integers to add was greater than 100!")
End If
End Sub 'Main
End Class 'ILLabelDemo
[C#]
using System;
using System.Threading;
using System.Reflection;
using System.Reflection.Emit;
class ILLabelDemo {
public static Type BuildAdderType() {
AppDomain myDomain = Thread.GetDomain();
AssemblyName myAsmName = new AssemblyName();
myAsmName.Name = "AdderExceptionAsm";
AssemblyBuilder myAsmBldr = myDomain.DefineDynamicAssembly(myAsmName,
AssemblyBuilderAccess.Run);
ModuleBuilder myModBldr = myAsmBldr.DefineDynamicModule("AdderExceptionMod");
TypeBuilder myTypeBldr = myModBldr.DefineType("Adder");
Type[] adderParams = new Type[] {typeof(int), typeof(int)};
// This method will add two numbers which are 100 or less. If either of the
// passed integer vales are greater than 100, it will return the value of -1.
MethodBuilder adderBldr = myTypeBldr.DefineMethod("DoAdd",
MethodAttributes.Public |
MethodAttributes.Static,
typeof(int),
adderParams);
ILGenerator adderIL = adderBldr.GetILGenerator();
// In order to successfully branch, we need to create labels
// representing the offset IL instruction block to branch to.
// These labels, when the MarkLabel(Label) method is invoked,
// will specify the IL instruction to branch to.
Label failed = adderIL.DefineLabel();
Label endOfMthd = adderIL.DefineLabel();
// First, load argument 0 and the integer value of "100" onto the
// stack. If arg0 > 100, branch to the label "failed", which is marked
// as the address of the block that loads -1 onto the stack, bypassing
// the addition.
adderIL.Emit(OpCodes.Ldarg_0);
adderIL.Emit(OpCodes.Ldc_I4_S, 100);
adderIL.Emit(OpCodes.Bgt_S, failed);
// Now, check to see if argument 1 was greater than 100. If it was,
// branch to "failed." Otherwise, fall through and perform the addition,
// branching unconditionally to the instruction at the label "endOfMthd".
adderIL.Emit(OpCodes.Ldarg_1);
adderIL.Emit(OpCodes.Ldc_I4_S, 100);
adderIL.Emit(OpCodes.Bgt_S, failed);
adderIL.Emit(OpCodes.Ldarg_0);
adderIL.Emit(OpCodes.Ldarg_1);
adderIL.Emit(OpCodes.Add_Ovf_Un);
adderIL.Emit(OpCodes.Br_S, endOfMthd);
// If this label is branched to (the failure case), load -1 onto the stack
// and fall through to the return opcode.
adderIL.MarkLabel(failed);
adderIL.Emit(OpCodes.Ldc_I4_M1);
// The end of the method. If both values were less than 100, the
// correct result will return. If one of the arguments was greater
// than 100, the result will be -1.
adderIL.MarkLabel(endOfMthd);
adderIL.Emit(OpCodes.Ret);
return myTypeBldr.CreateType();
}
public static void Main() {
Type adderType = BuildAdderType();
object addIns = Activator.CreateInstance(adderType);
object[] addParams = new object[2];
Console.Write("Enter an integer value: ");
addParams[0] = (object)Convert.ToInt32(Console.ReadLine());
Console.Write("Enter another integer value: ");
addParams[1] = (object)Convert.ToInt32(Console.ReadLine());
Console.WriteLine("---");
int adderResult = (int)adderType.InvokeMember("DoAdd",
BindingFlags.InvokeMethod,
null,
addIns,
addParams);
if (adderResult != -1) {
Console.WriteLine("{0} + {1} = {2}", addParams[0], addParams[1],
adderResult);
} else {
Console.WriteLine("One of the integers to add was greater than 100!");
}
}
}
[C++]
#using <mscorlib.dll>
using namespace System;
using namespace System::Threading;
using namespace System::Reflection;
using namespace System::Reflection::Emit;
Type* BuildAdderType() {
AppDomain* myDomain = Thread::GetDomain();
AssemblyName* myAsmName = new AssemblyName();
myAsmName->Name = S"AdderExceptionAsm";
AssemblyBuilder* myAsmBldr = myDomain->DefineDynamicAssembly(myAsmName,
AssemblyBuilderAccess::Run);
ModuleBuilder* myModBldr = myAsmBldr->DefineDynamicModule(S"AdderExceptionMod");
TypeBuilder* myTypeBldr = myModBldr->DefineType(S"Adder");
Type* adderParams[] = {__typeof(int), __typeof(int)};
// This method will add two numbers which are 100 or less. If either of the
// passed integer vales are greater than 100, it will return the value of -1.
MethodBuilder* adderBldr = myTypeBldr->DefineMethod(S"DoAdd",static_cast<MethodAttributes>(MethodAttributes::Public |
MethodAttributes::Static),
__typeof(int),
adderParams);
ILGenerator* adderIL = adderBldr->GetILGenerator();
// In order to successfully branch, we need to create labels
// representing the offset IL instruction block to branch to.
// These labels, when the MarkLabel(Label) method is invoked,
// will specify the IL instruction to branch to.
Label failed = adderIL->DefineLabel();
Label endOfMthd = adderIL->DefineLabel();
// First, load argument 0 and the integer value of "100" onto the
// stack. If arg0 > 100, branch to the label "failed", which is marked
// as the address of the block that loads -1 onto the stack, bypassing
// the addition.
adderIL->Emit(OpCodes::Ldarg_0);
adderIL->Emit(OpCodes::Ldc_I4_S, 100);
adderIL->Emit(OpCodes::Bgt_S, failed);
// Now, check to see if argument 1 was greater than 100. If it was,
// branch to "failed." Otherwise, fall through and perform the addition,
// branching unconditionally to the instruction at the label "endOfMthd".
adderIL->Emit(OpCodes::Ldarg_1);
adderIL->Emit(OpCodes::Ldc_I4_S, 100);
adderIL->Emit(OpCodes::Bgt_S, failed);
adderIL->Emit(OpCodes::Ldarg_0);
adderIL->Emit(OpCodes::Ldarg_1);
adderIL->Emit(OpCodes::Add_Ovf_Un);
adderIL->Emit(OpCodes::Br_S, endOfMthd);
// If this label is branched to (the failure case), load -1 onto the stack
// and fall through to the return opcode.
adderIL->MarkLabel(failed);
adderIL->Emit(OpCodes::Ldc_I4_M1);
// The end of the method. If both values were less than 100, the
// correct result will return. If one of the arguments was greater
// than 100, the result will be -1.
adderIL->MarkLabel(endOfMthd);
adderIL->Emit(OpCodes::Ret);
return myTypeBldr->CreateType();
}
int main() {
Type* adderType = BuildAdderType();
Object* addIns = Activator::CreateInstance(adderType);
Object* addParams[] = new Object*[2];
Console::Write(S"Enter an integer value: ");
addParams[0] = __box(Convert::ToInt32(Console::ReadLine()));
Console::Write(S"Enter another integer value: ");
addParams[1] = __box(Convert::ToInt32(Console::ReadLine()));
Console::WriteLine(S"---");
int adderResult = *dynamic_cast<int __gc *>(adderType->InvokeMember(S"DoAdd",
BindingFlags::InvokeMethod,
0,
addIns,
addParams));
if (adderResult != -1) {
Console::WriteLine(S" {0} + {1} = {2}", addParams[0], addParams[1], __box(adderResult));
} else {
Console::WriteLine(S"One of the integers to add was greater than 100!");
}
}
[JScript] JScript のサンプルはありません。Visual Basic、C#、および C++ のサンプルを表示するには、このページの左上隅にある言語のフィルタ ボタン .gif)
をクリックします。
必要条件
プラットフォーム: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 ファミリ
参照
ILGenerator クラス | ILGenerator メンバ | System.Reflection.Emit 名前空間