//引入命名空间
using System;
using System.Threading;
using System.Reflection;
using System.Reflection.Emit;
using System.Security.Permissions;
public class ILGenerator_BeginFinallyBlock
{
public static Type AddType()
{
// Create an assembly.
AssemblyName myAssemblyName = new AssemblyName();
myAssemblyName.Name = "AdderExceptionAsm";
// Create dynamic assembly.
AppDomain myAppDomain = Thread.GetDomain();
AssemblyBuilder myAssemblyBuilder = myAppDomain.DefineDynamicAssembly(myAssemblyName,
AssemblyBuilderAccess.Run);
// Create a dynamic module.
ModuleBuilder myModuleBuilder = myAssemblyBuilder.DefineDynamicModule("AdderExceptionMod");
TypeBuilder myTypeBuilder = myModuleBuilder.DefineType("Adder");
Type[] adderParams = new Type[] {typeof(int), typeof(int)};
// Define method to add two numbers.
MethodBuilder myMethodBuilder = myTypeBuilder.DefineMethod("DoAdd",MethodAttributes.Public |
MethodAttributes.Static,typeof(int),adderParams);
ILGenerator myAdderIL = myMethodBuilder.GetILGenerator();
// Create constructor.
ConstructorInfo myConstructorInfo = typeof(OverflowException).GetConstructor(
new Type[]{typeof(string)});
MethodInfo myExToStrMI = typeof(OverflowException).GetMethod("ToString");
MethodInfo myWriteLineMI = typeof(Console).GetMethod("WriteLine",new Type[]
{typeof(string),typeof(object)});
// Declare local variable.
LocalBuilder myLocalBuilder1 = myAdderIL.DeclareLocal(typeof(int));
LocalBuilder myLocalBuilder2 = myAdderIL.DeclareLocal(typeof(OverflowException));
// Define label.
Label myFailedLabel = myAdderIL.DefineLabel();
Label myEndOfMethodLabel = myAdderIL.DefineLabel();
// Begin exception block.
Label myLabel = myAdderIL.BeginExceptionBlock();
myAdderIL.Emit(OpCodes.Ldarg_0);
myAdderIL.Emit(OpCodes.Ldc_I4_S, 10);
myAdderIL.Emit(OpCodes.Bgt_S, myFailedLabel);
myAdderIL.Emit(OpCodes.Ldarg_1);
myAdderIL.Emit(OpCodes.Ldc_I4_S, 10);
myAdderIL.Emit(OpCodes.Bgt_S, myFailedLabel);
myAdderIL.Emit(OpCodes.Ldarg_0);
myAdderIL.Emit(OpCodes.Ldarg_1);
myAdderIL.Emit(OpCodes.Add_Ovf_Un);
myAdderIL.Emit(OpCodes.Stloc_S, myLocalBuilder1);
myAdderIL.Emit(OpCodes.Br_S, myEndOfMethodLabel);
myAdderIL.MarkLabel(myFailedLabel);
myAdderIL.Emit(OpCodes.Ldstr, "Cannot accept values over 10 for add.");
myAdderIL.Emit(OpCodes.Newobj, myConstructorInfo);
myAdderIL.Emit(OpCodes.Stloc_S, myLocalBuilder2);
myAdderIL.Emit(OpCodes.Ldloc_S, myLocalBuilder2);
// Throw the exception.
myAdderIL.ThrowException(typeof(OverflowException));
// Call 'BeginExceptFilterBlock'.
myAdderIL.BeginExceptFilterBlock();
myAdderIL.EmitWriteLine("Except filter block called.");
// Call catch block.
myAdderIL.BeginCatchBlock(null);
// Call other catch block.
myAdderIL.BeginCatchBlock(typeof(OverflowException));
myAdderIL.Emit(OpCodes.Ldstr, "{0}");
myAdderIL.Emit(OpCodes.Ldloc_S, myLocalBuilder2);
myAdderIL.EmitCall(OpCodes.Callvirt, myExToStrMI, null);
myAdderIL.EmitCall(OpCodes.Call, myWriteLineMI, null);
myAdderIL.Emit(OpCodes.Ldc_I4_M1);
myAdderIL.Emit(OpCodes.Stloc_S, myLocalBuilder1);
// Call finally block.
myAdderIL.BeginFinallyBlock();
myAdderIL.EmitWriteLine("Finally block called.");
// End the exception block.
myAdderIL.EndExceptionBlock();
myAdderIL.MarkLabel(myEndOfMethodLabel);
myAdderIL.Emit(OpCodes.Ldloc_S, myLocalBuilder1);
myAdderIL.Emit(OpCodes.Ret);
return myTypeBuilder.CreateType();
}
[PermissionSetAttribute(SecurityAction.Demand, Name="FullTrust")]
public static void Main()
{
Type myAddType = AddType();
object myObject1 = Activator.CreateInstance(myAddType);
object[] myObject2 = new object[]{15,15};
myAddType.InvokeMember("DoAdd", BindingFlags.InvokeMethod,
null, myObject1, myObject2);
}
}
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