PropertyBuilder Class (System.Reflection.Emit) (original) (raw)

• Reference

Definition

Defines the properties for a type.

public ref class PropertyBuilder abstract : System::Reflection::PropertyInfo

public ref class PropertyBuilder sealed : System::Reflection::PropertyInfo

public ref class PropertyBuilder sealed : System::Reflection::PropertyInfo, System::Runtime::InteropServices::_PropertyBuilder

public abstract class PropertyBuilder : System.Reflection.PropertyInfo

public sealed class PropertyBuilder : System.Reflection.PropertyInfo

[System.Runtime.InteropServices.ClassInterface(System.Runtime.InteropServices.ClassInterfaceType.None)]
public sealed class PropertyBuilder : System.Reflection.PropertyInfo, System.Runtime.InteropServices._PropertyBuilder

[System.Runtime.InteropServices.ClassInterface(System.Runtime.InteropServices.ClassInterfaceType.None)]
[System.Runtime.InteropServices.ComVisible(true)]
public sealed class PropertyBuilder : System.Reflection.PropertyInfo, System.Runtime.InteropServices._PropertyBuilder

type PropertyBuilder = class
    inherit PropertyInfo

[<System.Runtime.InteropServices.ClassInterface(System.Runtime.InteropServices.ClassInterfaceType.None)>]
type PropertyBuilder = class
    inherit PropertyInfo
    interface _PropertyBuilder

[<System.Runtime.InteropServices.ClassInterface(System.Runtime.InteropServices.ClassInterfaceType.None)>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type PropertyBuilder = class
    inherit PropertyInfo
    interface _PropertyBuilder

Public MustInherit Class PropertyBuilder
Inherits PropertyInfo

Public NotInheritable Class PropertyBuilder
Inherits PropertyInfo

Public NotInheritable Class PropertyBuilder
Inherits PropertyInfo
Implements _PropertyBuilder

Inheritance

Attributes

Implements

Examples

The following code sample demonstrates how to implement properties in a dynamic type using a PropertyBuilder obtained via TypeBuilder.DefineProperty to create the property framework and an associated MethodBuilder to implement the IL logic within the property.

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

class PropertyBuilderDemo
{
   public static Type BuildDynamicTypeWithProperties()
   {
        AppDomain myDomain = Thread.GetDomain();
        AssemblyName myAsmName = new AssemblyName();
        myAsmName.Name = "MyDynamicAssembly";

        // To generate a persistable assembly, specify AssemblyBuilderAccess.RunAndSave.
        AssemblyBuilder myAsmBuilder = myDomain.DefineDynamicAssembly(myAsmName,
                                                        AssemblyBuilderAccess.RunAndSave);
        // Generate a persistable single-module assembly.
        ModuleBuilder myModBuilder =
            myAsmBuilder.DefineDynamicModule(myAsmName.Name, myAsmName.Name + ".dll");

        TypeBuilder myTypeBuilder = myModBuilder.DefineType("CustomerData",
                                                        TypeAttributes.Public);

        FieldBuilder customerNameBldr = myTypeBuilder.DefineField("customerName",
                                                        typeof(string),
                                                        FieldAttributes.Private);

        // The last argument of DefineProperty is null, because the
        // property has no parameters. (If you don't specify null, you must
        // specify an array of Type objects. For a parameterless property,
        // use an array with no elements: new Type[] {})
        PropertyBuilder custNamePropBldr = myTypeBuilder.DefineProperty("CustomerName",
                                                         PropertyAttributes.HasDefault,
                                                         typeof(string),
                                                         null);

        // The property set and property get methods require a special
        // set of attributes.
        MethodAttributes getSetAttr =
            MethodAttributes.Public | MethodAttributes.SpecialName |
                MethodAttributes.HideBySig;

        // Define the "get" accessor method for CustomerName.
        MethodBuilder custNameGetPropMthdBldr =
            myTypeBuilder.DefineMethod("get_CustomerName",
                                       getSetAttr,
                                       typeof(string),
                                       Type.EmptyTypes);

        ILGenerator custNameGetIL = custNameGetPropMthdBldr.GetILGenerator();

        custNameGetIL.Emit(OpCodes.Ldarg_0);
        custNameGetIL.Emit(OpCodes.Ldfld, customerNameBldr);
        custNameGetIL.Emit(OpCodes.Ret);

        // Define the "set" accessor method for CustomerName.
        MethodBuilder custNameSetPropMthdBldr =
            myTypeBuilder.DefineMethod("set_CustomerName",
                                       getSetAttr,
                                       null,
                                       new Type[] { typeof(string) });

        ILGenerator custNameSetIL = custNameSetPropMthdBldr.GetILGenerator();

        custNameSetIL.Emit(OpCodes.Ldarg_0);
        custNameSetIL.Emit(OpCodes.Ldarg_1);
        custNameSetIL.Emit(OpCodes.Stfld, customerNameBldr);
        custNameSetIL.Emit(OpCodes.Ret);

        // Last, we must map the two methods created above to our PropertyBuilder to
        // their corresponding behaviors, "get" and "set" respectively.
        custNamePropBldr.SetGetMethod(custNameGetPropMthdBldr);
        custNamePropBldr.SetSetMethod(custNameSetPropMthdBldr);

        Type retval = myTypeBuilder.CreateType();

        // Save the assembly so it can be examined with Ildasm.exe,
        // or referenced by a test program.
        myAsmBuilder.Save(myAsmName.Name + ".dll");
        return retval;
   }

   public static void Main()
   {
        Type custDataType = BuildDynamicTypeWithProperties();

        PropertyInfo[] custDataPropInfo = custDataType.GetProperties();
        foreach (PropertyInfo pInfo in custDataPropInfo) {
           Console.WriteLine("Property '{0}' created!", pInfo.ToString());
        }

        Console.WriteLine("---");
        // Note that when invoking a property, you need to use the proper BindingFlags -
        // BindingFlags.SetProperty when you invoke the "set" behavior, and
        // BindingFlags.GetProperty when you invoke the "get" behavior. Also note that
        // we invoke them based on the name we gave the property, as expected, and not
        // the name of the methods we bound to the specific property behaviors.

        object custData = Activator.CreateInstance(custDataType);
        custDataType.InvokeMember("CustomerName", BindingFlags.SetProperty,
                                      null, custData, new object[]{ "Joe User" });

        Console.WriteLine("The customerName field of instance custData has been set to '{0}'.",
                           custDataType.InvokeMember("CustomerName", BindingFlags.GetProperty,
                                                      null, custData, new object[]{ }));
   }
}

// --- O U T P U T ---
// The output should be as follows:
// -------------------
// Property 'System.String CustomerName' created!
// ---
// The customerName field of instance custData has been set to 'Joe User'.
// -------------------

Imports System.Threading
Imports System.Reflection
Imports System.Reflection.Emit

Class PropertyBuilderDemo
   
   Public Shared Function BuildDynamicTypeWithProperties() As Type
      Dim myDomain As AppDomain = Thread.GetDomain()
      Dim myAsmName As New AssemblyName()
      myAsmName.Name = "MyDynamicAssembly"
      
      ' To generate a persistable assembly, specify AssemblyBuilderAccess.RunAndSave.
      Dim myAsmBuilder As AssemblyBuilder = myDomain.DefineDynamicAssembly(myAsmName, _
                                                        AssemblyBuilderAccess.RunAndSave)
      
      ' Generate a persistable, single-module assembly.
      Dim myModBuilder As ModuleBuilder = _
          myAsmBuilder.DefineDynamicModule(myAsmName.Name, myAsmName.Name & ".dll")
      
      Dim myTypeBuilder As TypeBuilder = myModBuilder.DefineType("CustomerData", TypeAttributes.Public)
      
      ' Define a private field to hold the property value.
      Dim customerNameBldr As FieldBuilder = myTypeBuilder.DefineField("customerName", _
                                             GetType(String), FieldAttributes.Private)
      
      ' The last argument of DefineProperty is Nothing, because the
      ' property has no parameters. (If you don't specify Nothing, you must
      ' specify an array of Type objects. For a parameterless property,
      ' use an array with no elements: New Type() {})
      Dim custNamePropBldr As PropertyBuilder = _
          myTypeBuilder.DefineProperty("CustomerName", _
                                       PropertyAttributes.HasDefault, _
                                       GetType(String), _
                                       Nothing)
      
      ' The property set and property get methods require a special
      ' set of attributes.
      Dim getSetAttr As MethodAttributes = _
          MethodAttributes.Public Or MethodAttributes.SpecialName _
              Or MethodAttributes.HideBySig

      ' Define the "get" accessor method for CustomerName.
      Dim custNameGetPropMthdBldr As MethodBuilder = _
          myTypeBuilder.DefineMethod("GetCustomerName", _
                                     getSetAttr, _
                                     GetType(String), _
                                     Type.EmptyTypes)
      
      Dim custNameGetIL As ILGenerator = custNameGetPropMthdBldr.GetILGenerator()
      
      custNameGetIL.Emit(OpCodes.Ldarg_0)
      custNameGetIL.Emit(OpCodes.Ldfld, customerNameBldr)
      custNameGetIL.Emit(OpCodes.Ret)
      
      ' Define the "set" accessor method for CustomerName.
      Dim custNameSetPropMthdBldr As MethodBuilder = _
          myTypeBuilder.DefineMethod("get_CustomerName", _
                                     getSetAttr, _
                                     Nothing, _
                                     New Type() {GetType(String)})
      
      Dim custNameSetIL As ILGenerator = custNameSetPropMthdBldr.GetILGenerator()
      
      custNameSetIL.Emit(OpCodes.Ldarg_0)
      custNameSetIL.Emit(OpCodes.Ldarg_1)
      custNameSetIL.Emit(OpCodes.Stfld, customerNameBldr)
      custNameSetIL.Emit(OpCodes.Ret)
      
      ' Last, we must map the two methods created above to our PropertyBuilder to 
      ' their corresponding behaviors, "get" and "set" respectively. 
      custNamePropBldr.SetGetMethod(custNameGetPropMthdBldr)
      custNamePropBldr.SetSetMethod(custNameSetPropMthdBldr)
            
      Dim retval As Type = myTypeBuilder.CreateType()

      ' Save the assembly so it can be examined with Ildasm.exe,
      ' or referenced by a test program.
      myAsmBuilder.Save(myAsmName.Name & ".dll")
      return retval
   End Function 'BuildDynamicTypeWithProperties
    
   
   Public Shared Sub Main()
      Dim custDataType As Type = BuildDynamicTypeWithProperties()
      
      Dim custDataPropInfo As PropertyInfo() = custDataType.GetProperties()
      Dim pInfo As PropertyInfo
      For Each pInfo In  custDataPropInfo
         Console.WriteLine("Property '{0}' created!", pInfo.ToString())
      Next pInfo
      
      Console.WriteLine("---")
      ' Note that when invoking a property, you need to use the proper BindingFlags -
      ' BindingFlags.SetProperty when you invoke the "set" behavior, and 
      ' BindingFlags.GetProperty when you invoke the "get" behavior. Also note that
      ' we invoke them based on the name we gave the property, as expected, and not
      ' the name of the methods we bound to the specific property behaviors.
      Dim custData As Object = Activator.CreateInstance(custDataType)
      custDataType.InvokeMember("CustomerName", BindingFlags.SetProperty, Nothing, _
                                custData, New Object() {"Joe User"})
      
      Console.WriteLine("The customerName field of instance custData has been set to '{0}'.", _
                        custDataType.InvokeMember("CustomerName", BindingFlags.GetProperty, _
                        Nothing, custData, New Object() {}))
   End Sub
End Class


' --- O U T P U T ---
' The output should be as follows:
' -------------------
' Property 'System.String CustomerName' created!
' ---
' The customerName field of instance custData has been set to 'Joe User'.
' -------------------

A PropertyBuilder is always associated with a TypeBuilder. The TypeBuilder. DefineProperty method will return a new PropertyBuilder to a client.

Constructors

Properties

Methods

Explicit Interface Implementations

Extension Methods

Applies to