DynamicMethod.GetILGenerator Method

Definition

Namespace:

System.Reflection.Emit

Assemblies:

netstandard.dll, System.Reflection.Emit.Lightweight.dll

Returns an MSIL generator that can be used to emit a body for the dynamic method.

Overloads

GetILGenerator(Int32)	Returns a Microsoft intermediate language (MSIL) generator for the method with the specified MSIL stream size.
GetILGenerator()	Returns a Microsoft intermediate language (MSIL) generator for the method with a default MSIL stream size of 64 bytes.

GetILGenerator(Int32)

Source:

DynamicMethod.CoreCLR.cs

Returns a Microsoft intermediate language (MSIL) generator for the method with the specified MSIL stream size.

C#

public System.Reflection.Emit.ILGenerator GetILGenerator(int streamSize);

Parameters

streamSize

Int32

The size of the MSIL stream, in bytes.

Returns

ILGenerator

An ILGenerator object for the method, with the specified MSIL stream size.

Examples

The following code example demonstrates this method overload. This code example is part of a larger example provided for the DynamicMethod class.

C#

// Create an array that specifies the parameter types of the
// overload of Console.WriteLine to be used in Hello.
Type[] writeStringArgs = {typeof(string)};
// Get the overload of Console.WriteLine that has one
// String parameter.
MethodInfo writeString = typeof(Console).GetMethod("WriteLine",
    writeStringArgs);

// Get an ILGenerator and emit a body for the dynamic method,
// using a stream size larger than the IL that will be
// emitted.
ILGenerator il = hello.GetILGenerator(256);
// Load the first argument, which is a string, onto the stack.
il.Emit(OpCodes.Ldarg_0);
// Call the overload of Console.WriteLine that prints a string.
il.EmitCall(OpCodes.Call, writeString, null);
// The Hello method returns the value of the second argument;
// to do this, load the onto the stack and return.
il.Emit(OpCodes.Ldarg_1);
il.Emit(OpCodes.Ret);

Remarks

After a dynamic method has been completed, by calling the CreateDelegate or Invoke method, any further attempt to add MSIL is ignored. No exception is thrown.

Примітка

There are restrictions on unverifiable code in dynamic methods, even in some full-trust scenarios. See the "Verification" section in Remarks for DynamicMethod.

See also

• How to: Define and Execute Dynamic Methods

GetILGenerator()

Source:

DynamicMethod.cs

Returns a Microsoft intermediate language (MSIL) generator for the method with a default MSIL stream size of 64 bytes.

C#

public System.Reflection.Emit.ILGenerator GetILGenerator();

Returns

ILGenerator

An ILGenerator object for the method.

Examples

The following code example creates a dynamic method that takes two parameters. The example emits a simple function body that prints the first parameter to the console, and the example uses the second parameter as the return value of the method. The example completes the method by creating a delegate, invokes the delegate with different parameters, and finally invokes the dynamic method using the Invoke method.

C#

using System;
using System.Reflection;
using System.Reflection.Emit;
using Microsoft.VisualBasic;

public class Test
{
    // Declare a delegate that will be used to execute the completed
    // dynamic method.
    private delegate int HelloInvoker(string msg, int ret);

    public static void Main()
    {
        // Create an array that specifies the types of the parameters
        // of the dynamic method. This method has a string parameter
        // and an int parameter.
        Type[] helloArgs = {typeof(string), typeof(int)};

        // Create a dynamic method with the name "Hello", a return type
        // of int, and two parameters whose types are specified by the
        // array helloArgs. Create the method in the module that
        // defines the Test class.
        DynamicMethod hello = new DynamicMethod("Hello",
            typeof(int),
            helloArgs,
            typeof(Test).Module);

        // Create an array that specifies the parameter types of the
        // overload of Console.WriteLine to be used in Hello.
        Type[] writeStringArgs = {typeof(string)};
        // Get the overload of Console.WriteLine that has one
        // String parameter.
        MethodInfo writeString =
            typeof(Console).GetMethod("WriteLine", writeStringArgs);

        // Get an ILGenerator and emit a body for the dynamic method.
        ILGenerator il = hello.GetILGenerator();
        // Load the first argument, which is a string, onto the stack.
        il.Emit(OpCodes.Ldarg_0);
        // Call the overload of Console.WriteLine that prints a string.
        il.EmitCall(OpCodes.Call, writeString, null);
        // The Hello method returns the value of the second argument;
        // to do this, load the onto the stack and return.
        il.Emit(OpCodes.Ldarg_1);
        il.Emit(OpCodes.Ret);

        // Create a delegate that represents the dynamic method. This
        // action completes the method, and any further attempts to
        // change the method will cause an exception.
        HelloInvoker hi =
            (HelloInvoker) hello.CreateDelegate(typeof(HelloInvoker));

        // Use the delegate to execute the dynamic method. Save and
        // print the return value.
        int retval = hi("\r\nHello, World!", 42);
        Console.WriteLine("Executing delegate hi(\"Hello, World!\", 42) returned {0}",
            retval);

        // Do it again, with different arguments.
        retval = hi("\r\nHi, Mom!", 5280);
        Console.WriteLine("Executing delegate hi(\"Hi, Mom!\", 5280) returned {0}",
            retval);

        // Create an array of arguments to use with the Invoke method.
        object[] invokeArgs = {"\r\nHello, World!", 42};
        // Invoke the dynamic method using the arguments. This is much
        // slower than using the delegate, because you must create an
        // array to contain the arguments, and ValueType arguments
        // must be boxed.
        object objRet = hello.Invoke(null, invokeArgs);
        Console.WriteLine("hello.Invoke returned {0}", objRet);
    }
}

Remarks

After a dynamic method has been completed, by calling the CreateDelegate or Invoke method, any further attempt to add MSIL is ignored. No exception is thrown.

Примітка

There are restrictions on unverifiable code in dynamic methods, even in some full-trust scenarios. See the "Verification" section in Remarks for DynamicMethod.

See also

• How to: Define and Execute Dynamic Methods