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ILGenerator.BeginScope Method

Begins a lexical scope.

Namespace:  System.Reflection.Emit
Assembly:  mscorlib (in mscorlib.dll)

public virtual void BeginScope()

ExceptionCondition
NotSupportedException

This ILGenerator belongs to a DynamicMethod.

This method is used to emit symbolic information. Local variables declared after BeginScope are scoped until the corresponding EndScope is called.

If the current ILGenerator is associated with a DynamicMethod object, it does not support symbolic information.

The following code sample illustrates the use of BeginScope and EndScope.

// Get the current AppDomain.
AppDomain myAppDomain = AppDomain.CurrentDomain;
AssemblyName myAssemblyName = new AssemblyName();
myAssemblyName.Name = "SampleAssembly";

// Create a dynamic assembly 'myAssembly' with access mode 'Run'.
AssemblyBuilder myAssembly = myAppDomain.DefineDynamicAssembly(
                        myAssemblyName, AssemblyBuilderAccess.Run);
// Create a dynamic module 'myModule' in 'myAssembly'.
ModuleBuilder myModule=myAssembly.DefineDynamicModule("MyDynamicModule",true);
// Define a public class 'MyDynamicClass'.
TypeBuilder myTypeBuilder = myModule.DefineType("MyDynamicClass",
                                 TypeAttributes.Public);
// Define a public string field.
FieldBuilder myField = myTypeBuilder.DefineField("MyDynamicField", 
                         typeof(String), FieldAttributes.Public);
// Create the constructor.
Type[] myConstructorArgs = {typeof(String)};
ConstructorBuilder myConstructor = myTypeBuilder.DefineConstructor(
   MethodAttributes.Public, CallingConventions.Standard, myConstructorArgs);

// Generate IL for 'myConstructor'.
ILGenerator myConstructorIL = myConstructor.GetILGenerator();
// Emit the necessary opcodes.
myConstructorIL.Emit(OpCodes.Ldarg_0);
ConstructorInfo mySuperConstructor = typeof(Object).GetConstructor(new Type[0]);
myConstructorIL.Emit(OpCodes.Call, mySuperConstructor);
myConstructorIL.Emit(OpCodes.Ldarg_0);
myConstructorIL.Emit(OpCodes.Ldarg_1);
myConstructorIL.Emit(OpCodes.Stfld, myField);
myConstructorIL.Emit(OpCodes.Ret);

// Define a dynamic method named 'MyDynamicMethod'.
MethodBuilder myMethod = myTypeBuilder.DefineMethod("MyDynamicMethod",
   MethodAttributes.Public, typeof(String), null);
// Generate IL for 'myMethod'.
ILGenerator myMethodIL = myMethod.GetILGenerator();

// Begin the scope for a local variable.
myMethodIL.BeginScope();

LocalBuilder myLocalBuilder = myMethodIL.DeclareLocal(typeof(int));
Console.WriteLine("\nTrying to access the local variable within the scope.");
Console.WriteLine("'myLocalBuilder' type is: {0}", myLocalBuilder.LocalType);
myMethodIL.Emit(OpCodes.Ldstr, "Local value");
myMethodIL.Emit(OpCodes.Stloc_0, myLocalBuilder);

// End the scope of 'myLocalBuilder'.
myMethodIL.EndScope();

// Access the local variable outside the scope.
Console.WriteLine("\nTrying to access the local variable outside the scope:");
myMethodIL.Emit(OpCodes.Stloc_0, myLocalBuilder);
myMethodIL.Emit(OpCodes.Ldloc_0 );
myMethodIL.Emit(OpCodes.Ret );

// Create 'MyDynamicClass' class.
Type myType1 = myTypeBuilder.CreateType();

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone 8, Silverlight 8.1

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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