MethodBuilder Class

Definition

Namespace:

System.Reflection.Emit

Assembly:

System.Reflection.Emit.dll

Source:

MethodBuilder.cs

Defines and represents a method (or constructor) on a dynamic class.

public ref class MethodBuilder abstract : System::Reflection::MethodInfo

public abstract class MethodBuilder : System.Reflection.MethodInfo

type MethodBuilder = class
    inherit MethodInfo

Public MustInherit Class MethodBuilder
Inherits MethodInfo

Inheritance

Object

MemberInfo

MethodBase

MethodInfo

MethodBuilder

Examples

The following example uses the MethodBuilder class to create a method within a dynamic type.

using namespace System;
using namespace System::Reflection;
using namespace System::Reflection::Emit;

void AddMethodDynamically( TypeBuilder^ myTypeBld, 
                           String^ mthdName, 
                           array<Type^>^ mthdParams, 
                           Type^ returnType, 
                           String^ mthdAction )
{
   MethodBuilder^ myMthdBld = myTypeBld->DefineMethod( mthdName, static_cast<MethodAttributes>(MethodAttributes::Public | MethodAttributes::Static), returnType, mthdParams );
   ILGenerator^ ILOut = myMthdBld->GetILGenerator();
   int numParams = mthdParams->Length;
   for ( Byte x = 0; x < numParams; x++ )
   {
      ILOut->Emit( OpCodes::Ldarg_S, x );

   }
   if ( numParams > 1 )
   {
      for ( int y = 0; y < (numParams - 1); y++ )
      {
         if ( mthdAction->Equals( "A" ) )
                  ILOut->Emit( OpCodes::Add );
         else
         if ( mthdAction->Equals( "M" ) )
                  ILOut->Emit( OpCodes::Mul );
         else
                  ILOut->Emit( OpCodes::Add );

      }
   }

   ILOut->Emit( OpCodes::Ret );
};

void main()
{
   AppDomain^ myDomain = AppDomain::CurrentDomain;
   AssemblyName^ asmName = gcnew AssemblyName;
   asmName->Name = "MyDynamicAsm";
   AssemblyBuilder^ myAsmBuilder = myDomain->DefineDynamicAssembly( asmName, 
                                                                    AssemblyBuilderAccess::RunAndSave );
   ModuleBuilder^ myModule = myAsmBuilder->DefineDynamicModule( "MyDynamicAsm", 
                                                                "MyDynamicAsm.dll" );
   TypeBuilder^ myTypeBld = myModule->DefineType( "MyDynamicType", 
                                                  TypeAttributes::Public );
   
   // Get info from the user to build the method dynamically.
   Console::WriteLine( "Let's build a simple method dynamically!" );
   Console::WriteLine( "Please enter a few numbers, separated by spaces." );
   String^ inputNums = Console::ReadLine();
   Console::Write( "Do you want to [A]dd (default) or [M]ultiply these numbers? " );
   String^ myMthdAction = Console::ReadLine()->ToUpper();
   Console::Write( "Lastly, what do you want to name your new dynamic method? " );
   String^ myMthdName = Console::ReadLine();
   
   // Process inputNums into an array and create a corresponding Type array
   int index = 0;
   array<String^>^inputNumsList = inputNums->Split();
   array<Type^>^myMthdParams = gcnew array<Type^>(inputNumsList->Length);
   array<Object^>^inputValsList = gcnew array<Object^>(inputNumsList->Length);
   for each (String^ inputNum in inputNumsList)
   {
      inputValsList[ index ] = Convert::ToInt32( inputNum );
      myMthdParams[ index ] = int::typeid;
      index++;
   }

   
   // Now, call the method building method with the parameters, passing the
   // TypeBuilder by reference.
   AddMethodDynamically( myTypeBld, 
                         myMthdName, 
                         myMthdParams, 
                         int::typeid, 
                         myMthdAction );
   Type^ myType = myTypeBld->CreateType();

   Console::WriteLine( "---" );
   Console::WriteLine( "The result of {0} the inputted values is: {1}", 
                       ((myMthdAction->Equals( "M" )) ? "multiplying" : "adding"), 
                       myType->InvokeMember( myMthdName, 
                                             BindingFlags::InvokeMethod | BindingFlags::Public | BindingFlags::Static, 
                       nullptr, 
                       nullptr, 
                       inputValsList ) );
   Console::WriteLine( "---" );
   
   // Let's take a look at the method we created.
   // If you are interested in seeing the MSIL generated dynamically for the method
   // your program generated, change to the directory where you ran the compiled
   // code sample and type "ildasm MyDynamicAsm.dll" at the prompt. When the list
   // of manifest contents appears, click on "MyDynamicType" and then on the name of
   // of the method you provided during execution.

   myAsmBuilder->Save( "MyDynamicAsm.dll" );

   MethodInfo^ myMthdInfo = myType->GetMethod( myMthdName );
   Console::WriteLine( "Your Dynamic Method: {0};", myMthdInfo );
}

using System;
using System.Reflection;
using System.Reflection.Emit;

class DemoMethodBuilder
{
    public static void AddMethodDynamically (TypeBuilder myTypeBld,
                                             string mthdName,
                                             Type[] mthdParams,
                                             Type returnType,
                                             string mthdAction)
    {

        MethodBuilder myMthdBld = myTypeBld.DefineMethod(
                                             mthdName,
                                             MethodAttributes.Public |
                                             MethodAttributes.Static,
                                             returnType,
                                             mthdParams);

        ILGenerator ILout = myMthdBld.GetILGenerator();

        int numParams = mthdParams.Length;

        for (byte x=0; x < numParams; x++)
        {
            ILout.Emit(OpCodes.Ldarg_S, x);
        }

        if (numParams > 1)
        {
            for (int y=0; y<(numParams-1); y++)
            {
                switch (mthdAction)
                {
                    case "A": ILout.Emit(OpCodes.Add);
                              break;
                    case "M": ILout.Emit(OpCodes.Mul);
                              break;
                    default: ILout.Emit(OpCodes.Add);
                              break;
                }
            }
        }
        ILout.Emit(OpCodes.Ret);
    }

    public static void Main()
    {
        AppDomain myDomain = AppDomain.CurrentDomain;
        AssemblyName asmName = new AssemblyName();
        asmName.Name = "MyDynamicAsm";

        AssemblyBuilder myAsmBuilder = myDomain.DefineDynamicAssembly(
                                       asmName,
                                       AssemblyBuilderAccess.RunAndSave);

        ModuleBuilder myModule = myAsmBuilder.DefineDynamicModule("MyDynamicAsm",
                                                                  "MyDynamicAsm.dll");

        TypeBuilder myTypeBld = myModule.DefineType("MyDynamicType",
                                                    TypeAttributes.Public);

        // Get info from the user to build the method dynamically.
        Console.WriteLine("Let's build a simple method dynamically!");
        Console.WriteLine("Please enter a few numbers, separated by spaces.");
        string inputNums = Console.ReadLine();
        Console.Write("Do you want to [A]dd (default) or [M]ultiply these numbers? ");
        string myMthdAction = Console.ReadLine().ToUpper();
        Console.Write("Lastly, what do you want to name your new dynamic method? ");
        string myMthdName = Console.ReadLine();

        // Process inputNums into an array and create a corresponding Type array
        int index = 0;
        string[] inputNumsList = inputNums.Split();

        Type[] myMthdParams = new Type[inputNumsList.Length];
        object[] inputValsList = new object[inputNumsList.Length];

        foreach (string inputNum in inputNumsList)
        {
            inputValsList[index] = (object)Convert.ToInt32(inputNum);
                myMthdParams[index] = typeof(int);
                index++;
        }

        // Now, call the method building method with the parameters, passing the
        // TypeBuilder by reference.
        AddMethodDynamically(myTypeBld,
                             myMthdName,
                             myMthdParams,
                             typeof(int),
                             myMthdAction);

        Type myType = myTypeBld.CreateType();

        Console.WriteLine("---");
        Console.WriteLine("The result of {0} the inputted values is: {1}",
                          ((myMthdAction == "M") ? "multiplying" : "adding"),
                          myType.InvokeMember(myMthdName,
                          BindingFlags.InvokeMethod | BindingFlags.Public |
                          BindingFlags.Static,
                          null,
                          null,
                          inputValsList));
        Console.WriteLine("---");

        // Let's take a look at the method we created.
        // If you are interested in seeing the MSIL generated dynamically for the method
        // your program generated, change to the directory where you ran the compiled
        // code sample and type "ildasm MyDynamicAsm.dll" at the prompt. When the list
        // of manifest contents appears, click on "MyDynamicType" and then on the name of
        // of the method you provided during execution.

        myAsmBuilder.Save("MyDynamicAsm.dll");

        MethodInfo myMthdInfo = myType.GetMethod(myMthdName);
        Console.WriteLine("Your Dynamic Method: {0};", myMthdInfo.ToString());
    }
}

Imports System.Reflection
Imports System.Reflection.Emit

Class DemoMethodBuilder
   
   Public Shared Sub AddMethodDynamically(ByVal myTypeBld As TypeBuilder, _
                                          ByVal mthdName As String, _
                                          ByVal mthdParams() As Type, _
                                          ByVal returnType As Type, _
                                          ByVal mthdAction As String)
      
      Dim myMthdBld As MethodBuilder = myTypeBld.DefineMethod(mthdName, _
                                       MethodAttributes.Public Or MethodAttributes.Static, _
                                       returnType, _
                                       mthdParams)
      
      Dim ILout As ILGenerator = myMthdBld.GetILGenerator()
      
      Dim numParams As Integer = mthdParams.Length
      
      Dim x As Byte
      For x = 0 To numParams - 1
         ILout.Emit(OpCodes.Ldarg_S, x)
      Next x
      
      If numParams > 1 Then
         Dim y As Integer
         For y = 0 To (numParams - 1) - 1
            Select Case mthdAction
               Case "A"
                  ILout.Emit(OpCodes.Add)
               Case "M"
                  ILout.Emit(OpCodes.Mul)
               Case Else
                  ILout.Emit(OpCodes.Add)
            End Select
         Next y
      End If
      ILout.Emit(OpCodes.Ret)
   End Sub 
    
   
   Public Shared Sub Main()
      
      Dim myDomain As AppDomain = AppDomain.CurrentDomain
      Dim asmName As New AssemblyName()
      asmName.Name = "MyDynamicAsm"
      
      Dim myAsmBuilder As AssemblyBuilder = myDomain.DefineDynamicAssembly(asmName, _
                                            AssemblyBuilderAccess.RunAndSave)
      
      Dim myModule As ModuleBuilder = myAsmBuilder.DefineDynamicModule("MyDynamicAsm", _
                                                                       "MyDynamicAsm.dll")
      
      Dim myTypeBld As TypeBuilder = myModule.DefineType("MyDynamicType", TypeAttributes.Public)
      
      ' Get info from the user to build the method dynamically.
      Console.WriteLine("Let's build a simple method dynamically!")
      Console.WriteLine("Please enter a few numbers, separated by spaces.")
      Dim inputNums As String = Console.ReadLine()
      Console.Write("Do you want to [A]dd (default) or [M]ultiply these numbers? ")
      Dim myMthdAction As String = Console.ReadLine().ToUpper()
      Console.Write("Lastly, what do you want to name your new dynamic method? ")
      Dim myMthdName As String = Console.ReadLine()
      
      ' Process inputNums into an array and create a corresponding Type array 
      Dim index As Integer = 0
      Dim inputNumsList As String() = inputNums.Split()
      
      Dim myMthdParams(inputNumsList.Length - 1) As Type
      Dim inputValsList(inputNumsList.Length - 1) As Object
      
      
      Dim inputNum As String
      For Each inputNum In  inputNumsList
         inputValsList(index) = CType(Convert.ToInt32(inputNum), Object)
         myMthdParams(index) = GetType(Integer)
         index += 1
      Next inputNum
      
      ' Now, call the method building method with the parameters, passing the 
      ' TypeBuilder by reference.
      AddMethodDynamically(myTypeBld, myMthdName, myMthdParams, GetType(Integer), myMthdAction)
      
      Dim myType As Type = myTypeBld.CreateType()
     
      Dim description as String 
      If myMthdAction = "M" Then
         description = "multiplying"
      Else
         description = "adding"
      End If

      Console.WriteLine("---")
      Console.WriteLine("The result of {0} the values is: {1}", _
                         description, _
                         myType.InvokeMember(myMthdName, _
                                             BindingFlags.InvokeMethod _
                                               Or BindingFlags.Public _
                                               Or BindingFlags.Static, _
                                             Nothing, _
                                             Nothing, _
                                             inputValsList)) 
      Console.WriteLine("---")

      ' If you are interested in seeing the MSIL generated dynamically for the method
      ' your program generated, change to the directory where you ran the compiled
      ' code sample and type "ildasm MyDynamicAsm.dll" at the prompt. When the list
      ' of manifest contents appears, click on "MyDynamicType" and then on the name of
      ' of the method you provided during execution.
 
      myAsmBuilder.Save("MyDynamicAsm.dll") 

      Dim myMthdInfo As MethodInfo = myType.GetMethod(myMthdName)
      Console.WriteLine("Your Dynamic Method: {0};", myMthdInfo.ToString())
   End Sub 
End Class

Remarks

For more information about this API, see Supplemental API remarks for MethodBuilder.

Constructors

MethodBuilder()

Initializes a new instance of the MethodBuilder class.

Properties

Attributes	Retrieves the attributes for this method.
CallingConvention	Returns the calling convention of the method.
ContainsGenericParameters	Not supported for this type.
CustomAttributes	Gets a collection that contains this member's custom attributes. (Inherited from MemberInfo)
DeclaringType	Returns the type that declares this method.
InitLocals	Gets or sets a Boolean value that specifies whether the local variables in this method are zero initialized. The default value of this property is true.
InitLocalsCore	When overridden in a derived class, gets or sets a value that indicates whether the local variables in this method are zero-initialized.
IsAbstract	Gets a value indicating whether the method is abstract. (Inherited from MethodBase)
IsAssembly	Gets a value indicating whether the potential visibility of this method or constructor is described by Assembly; that is, the method or constructor is visible at most to other types in the same assembly, and is not visible to derived types outside the assembly. (Inherited from MethodBase)
IsCollectible	Gets a value that indicates whether this MemberInfo object is part of an assembly held in a collectible AssemblyLoadContext. (Inherited from MemberInfo)
IsConstructedGenericMethod	(Inherited from MethodBase)
IsConstructor	Gets a value indicating whether the method is a constructor. (Inherited from MethodBase)
IsFamily	Gets a value indicating whether the visibility of this method or constructor is described by Family; that is, the method or constructor is visible only within its class and derived classes. (Inherited from MethodBase)
IsFamilyAndAssembly	Gets a value indicating whether the visibility of this method or constructor is described by FamANDAssem; that is, the method or constructor can be called by derived classes, but only if they are in the same assembly. (Inherited from MethodBase)
IsFamilyOrAssembly	Gets a value indicating whether the potential visibility of this method or constructor is described by FamORAssem; that is, the method or constructor can be called by derived classes wherever they are, and by classes in the same assembly. (Inherited from MethodBase)
IsFinal	Gets a value indicating whether this method is final. (Inherited from MethodBase)
IsGenericMethod	Gets a value indicating whether the method is a generic method.
IsGenericMethodDefinition	Gets a value indicating whether the current MethodBuilder object represents the definition of a generic method.
IsHideBySig	Gets a value indicating whether only a member of the same kind with exactly the same signature is hidden in the derived class. (Inherited from MethodBase)
IsPrivate	Gets a value indicating whether this member is private. (Inherited from MethodBase)
IsPublic	Gets a value indicating whether this is a public method. (Inherited from MethodBase)
IsSecurityCritical	Throws a NotSupportedException in all cases.
IsSecuritySafeCritical	Throws a NotSupportedException in all cases.
IsSecurityTransparent	Throws a NotSupportedException in all cases.
IsSpecialName	Gets a value indicating whether this method has a special name. (Inherited from MethodBase)
IsStatic	Gets a value indicating whether the method is static. (Inherited from MethodBase)
IsVirtual	Gets a value indicating whether the method is virtual. (Inherited from MethodBase)
MemberType	Gets a MemberTypes value indicating that this member is a method. (Inherited from MethodInfo)
MetadataToken	Gets a token that identifies the current dynamic module in metadata.
MethodHandle	Retrieves the internal handle for the method. Use this handle to access the underlying metadata handle.
MethodImplementationFlags	Gets the MethodImplAttributes flags that specify the attributes of a method implementation. (Inherited from MethodBase)
Module	Gets the module in which the current method is being defined.
Name	Retrieves the name of this method.
ReflectedType	Retrieves the class that was used in reflection to obtain this object.
ReturnParameter	Gets a ParameterInfo object that contains information about the return type of the method, such as whether the return type has custom modifiers.
ReturnType	Gets the return type of the method represented by this MethodBuilder.
ReturnTypeCustomAttributes	Returns the custom attributes of the method's return type.

Methods

CreateDelegate(Type)	Creates a delegate of the specified type from this method. (Inherited from MethodInfo)
CreateDelegate(Type, Object)	Creates a delegate of the specified type with the specified target from this method. (Inherited from MethodInfo)
CreateDelegate<T>()	Creates a delegate of type T from this method. (Inherited from MethodInfo)
CreateDelegate<T>(Object)	Creates a delegate of type T with the specified target from this method. (Inherited from MethodInfo)
DefineGenericParameters(String[])	Sets the number of generic type parameters for the current method, specifies their names, and returns an array of GenericTypeParameterBuilder objects that can be used to define their constraints.
DefineGenericParametersCore(String[])	When overridden in a derived class, sets the number of generic type parameters for the current method, specifies their names, and returns an array of GenericTypeParameterBuilder objects that can be used to define their constraints.
DefineParameter(Int32, ParameterAttributes, String)	Sets the parameter attributes and the name of a parameter of this method, or of the return value of this method. Returns a ParameterBuilder that can be used to apply custom attributes.
DefineParameterCore(Int32, ParameterAttributes, String)	When overridden in a derived class, defines a parameter or return parameter for this method.
Equals(Object)	Determines whether the given object is equal to this instance.
GetBaseDefinition()	Return the base implementation for a method.
GetCustomAttributes(Boolean)	Returns all the custom attributes defined for this method.
GetCustomAttributes(Type, Boolean)	Returns the custom attributes identified by the given type.
GetCustomAttributesData()	Returns a list of CustomAttributeData objects representing data about the attributes that have been applied to the target member. (Inherited from MemberInfo)
GetGenericArguments()	Returns an array of GenericTypeParameterBuilder objects that represent the type parameters of the method, if it is generic.
GetGenericMethodDefinition()	Returns this method.
GetHashCode()	Gets the hash code for this method.
GetILGenerator()	Returns an ILGenerator for this method with a default Microsoft intermediate language (MSIL) stream size of 64 bytes.
GetILGenerator(Int32)	Returns an ILGenerator for this method with the specified Microsoft intermediate language (MSIL) stream size.
GetILGeneratorCore(Int32)	When overridden in a derived class, gets an ILGenerator that can be used to emit a method body for this method.
GetMethodBody()	When overridden in a derived class, gets a MethodBody object that provides access to the MSIL stream, local variables, and exceptions for the current method. (Inherited from MethodBase)
GetMethodImplementationFlags()	Returns the implementation flags for the method.
GetParameters()	Returns the parameters of this method.
GetType()	Discovers the attributes of a method and provides access to method metadata. (Inherited from MethodInfo)
HasSameMetadataDefinitionAs(MemberInfo)	(Inherited from MemberInfo)
Invoke(Object, BindingFlags, Binder, Object[], CultureInfo)	Dynamically invokes the method reflected by this instance on the given object, passing along the specified parameters, and under the constraints of the given binder.
Invoke(Object, Object[])	Invokes the method or constructor represented by the current instance, using the specified parameters. (Inherited from MethodInfo)
IsDefined(Type, Boolean)	Checks if the specified custom attribute type is defined.
MakeGenericMethod(Type[])	Returns a generic method constructed from the current generic method definition using the specified generic type arguments.
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
SetCustomAttribute(ConstructorInfo, Byte[])	Sets a custom attribute using a specified custom attribute blob.
SetCustomAttribute(CustomAttributeBuilder)	Sets a custom attribute using a custom attribute builder.
SetCustomAttributeCore(ConstructorInfo, ReadOnlySpan<Byte>)	When overridden in a derived class, sets a custom attribute on this assembly.
SetImplementationFlags(MethodImplAttributes)	Sets the implementation flags for this method.
SetImplementationFlagsCore(MethodImplAttributes)	When overridden in a derived class, sets the implementation flags for this method.
SetParameters(Type[])	Sets the number and types of parameters for a method.
SetReturnType(Type)	Sets the return type of the method.
SetSignature(Type, Type[], Type[], Type[], Type[][], Type[][])	Sets the method signature, including the return type, the parameter types, and the required and optional custom modifiers of the return type and parameter types.
SetSignatureCore(Type, Type[], Type[], Type[], Type[][], Type[][])	When overridden in a derived class, sets the method signature, including the return type, the parameter types, and the required and optional custom modifiers of the return type and parameter types.
ToString()	Returns this MethodBuilder instance as a string.

Extension Methods

GetCustomAttribute(MemberInfo, Type)	Retrieves a custom attribute of a specified type that is applied to a specified member.
GetCustomAttribute(MemberInfo, Type, Boolean)	Retrieves a custom attribute of a specified type that is applied to a specified member, and optionally inspects the ancestors of that member.
GetCustomAttribute<T>(MemberInfo)	Retrieves a custom attribute of a specified type that is applied to a specified member.
GetCustomAttribute<T>(MemberInfo, Boolean)	Retrieves a custom attribute of a specified type that is applied to a specified member, and optionally inspects the ancestors of that member.
GetCustomAttributes(MemberInfo)	Retrieves a collection of custom attributes that are applied to a specified member.
GetCustomAttributes(MemberInfo, Boolean)	Retrieves a collection of custom attributes that are applied to a specified member, and optionally inspects the ancestors of that member.
GetCustomAttributes(MemberInfo, Type)	Retrieves a collection of custom attributes of a specified type that are applied to a specified member.
GetCustomAttributes(MemberInfo, Type, Boolean)	Retrieves a collection of custom attributes of a specified type that are applied to a specified member, and optionally inspects the ancestors of that member.
GetCustomAttributes<T>(MemberInfo)	Retrieves a collection of custom attributes of a specified type that are applied to a specified member.
GetCustomAttributes<T>(MemberInfo, Boolean)	Retrieves a collection of custom attributes of a specified type that are applied to a specified member, and optionally inspects the ancestors of that member.
IsDefined(MemberInfo, Type)	Indicates whether custom attributes of a specified type are applied to a specified member.
IsDefined(MemberInfo, Type, Boolean)	Indicates whether custom attributes of a specified type are applied to a specified member, and, optionally, applied to its ancestors.
GetMetadataToken(MemberInfo)	Gets a metadata token for the given member, if available.
HasMetadataToken(MemberInfo)	Returns a value that indicates whether a metadata token is available for the specified member.
GetBaseDefinition(MethodInfo)
GetRuntimeBaseDefinition(MethodInfo)	Retrieves an object that represents the specified method on the direct or indirect base class where the method was first declared.