PropertyBuilder Class

Definition

Defines the properties for a type.

[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
Inheritance
Attributes
Implements

Inherited Members

System.Object

System.Reflection.MemberInfo

System.Reflection.PropertyInfo

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 namespace System;
using namespace System::Threading;
using namespace System::Reflection;
using namespace System::Reflection::Emit;
Type^ BuildDynamicTypeWithProperties()
{
   AppDomain^ myDomain = Thread::GetDomain();
   AssemblyName^ myAsmName = gcnew 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 );

   // Define a private field to hold the property value.
   FieldBuilder^ customerNameBldr = myTypeBuilder->DefineField( "customerName", String::typeid, FieldAttributes::Private );
   
   // The last argument of DefineProperty is an empty array of Type
   // objects, because the property has no parameters. (Alternatively,
   // you can specify a null value.)
   PropertyBuilder^ custNamePropBldr = 
       myTypeBuilder->DefineProperty( "CustomerName", PropertyAttributes::HasDefault, String::typeid, gcnew array<Type^>(0) );
   
   // 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,
                                    String::typeid, 
                                    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.
   array<Type^>^temp2 = {String::typeid};
   MethodBuilder^ custNameSetPropMthdBldr = 
       myTypeBuilder->DefineMethod( "set_CustomerName", 
                                    getSetAttr,
                                    nullptr, 
                                    temp2 );

   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;
}

int main()
{
   Type^ custDataType = BuildDynamicTypeWithProperties();
   array<PropertyInfo^>^custDataPropInfo = custDataType->GetProperties();
   System::Collections::IEnumerator^ myEnum = custDataPropInfo->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      PropertyInfo^ pInfo = safe_cast<PropertyInfo^>(myEnum->Current);
      Console::WriteLine( "Property '{0}' created!", 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.
   Object^ custData = Activator::CreateInstance( custDataType );
   array<Object^>^temp3 = {"Joe User"};
   custDataType->InvokeMember( "CustomerName", BindingFlags::SetProperty, nullptr, custData, temp3 );
   Console::WriteLine( "The customerName field of instance custData has been set to '{0}'.", custDataType->InvokeMember( "CustomerName", BindingFlags::GetProperty, nullptr, custData, gcnew array<Object^>(0) ) );
}

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

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 [System.String]' created!
// ---
// The customerName field of instance custData has been set to 'Joe User'.
// -------------------

Imports System
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 'Main
End Class 'PropertyBuilderDemo


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

Remarks

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

Properties

Attributes

Gets the attributes for this property.

CanRead

Gets a value indicating whether the property can be read.

CanWrite

Gets a value indicating whether the property can be written to.

DeclaringType

Gets the class that declares this member.

Module

Gets the module in which the type that declares the current property is being defined.

Name

Gets the name of this member.

PropertyToken

Retrieves the token for this property.

PropertyType

Gets the type of the field of this property.

ReflectedType

Gets the class object that was used to obtain this instance of MemberInfo.

Methods

AddOtherMethod(MethodBuilder)

Adds one of the other methods associated with this property.

GetAccessors(Boolean)

Returns an array of the public and non-public get and set accessors on this property.

GetCustomAttributes(Boolean)

Returns an array of all the custom attributes for this property.

GetCustomAttributes(Type, Boolean)

Returns an array of custom attributes identified by Type.

GetGetMethod(Boolean)

Returns the public and non-public get accessor for this property.

GetIndexParameters()

Returns an array of all the index parameters for the property.

GetSetMethod(Boolean)

Returns the set accessor for this property.

GetValue(Object, Object[])

Gets the value of the indexed property by calling the property's getter method.

GetValue(Object, BindingFlags, Binder, Object[], CultureInfo)

Gets the value of a property having the specified binding, index, and CultureInfo.

IsDefined(Type, Boolean)

Indicates whether one or more instance of attributeType is defined on this property.

SetConstant(Object)

Sets the default value of this property.

SetCustomAttribute(CustomAttributeBuilder)

Set a custom attribute using a custom attribute builder.

SetCustomAttribute(ConstructorInfo, Byte[])

Set a custom attribute using a specified custom attribute blob.

SetGetMethod(MethodBuilder)

Sets the method that gets the property value.

SetSetMethod(MethodBuilder)

Sets the method that sets the property value.

SetValue(Object, Object, Object[])

Sets the value of the property with optional index values for index properties.

SetValue(Object, Object, BindingFlags, Binder, Object[], CultureInfo)

Sets the property value for the given object to the given value.

Explicit Interface Implementations

_PropertyBuilder.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr)

Maps a set of names to a corresponding set of dispatch identifiers.

_PropertyBuilder.GetTypeInfo(UInt32, UInt32, IntPtr)

Retrieves the type information for an object, which can then be used to get the type information for an interface.

_PropertyBuilder.GetTypeInfoCount(UInt32)

Retrieves the number of type information interfaces that an object provides (either 0 or 1).

_PropertyBuilder.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr)

Provides access to properties and methods exposed by an object.

Extension Methods

GetCustomAttribute(MemberInfo, Type)
GetCustomAttribute(MemberInfo, Type, Boolean)
GetCustomAttribute<T>(MemberInfo)
GetCustomAttribute<T>(MemberInfo, Boolean)
GetCustomAttributes(MemberInfo)
GetCustomAttributes(MemberInfo, Boolean)
GetCustomAttributes(MemberInfo, Type)
GetCustomAttributes(MemberInfo, Type, Boolean)
GetCustomAttributes<T>(MemberInfo)
GetCustomAttributes<T>(MemberInfo, Boolean)
IsDefined(MemberInfo, Type)
IsDefined(MemberInfo, Type, Boolean)
GetMetadataToken(MemberInfo)
HasMetadataToken(MemberInfo)
GetAccessors(PropertyInfo)
GetAccessors(PropertyInfo, Boolean)
GetGetMethod(PropertyInfo)
GetGetMethod(PropertyInfo, Boolean)
GetSetMethod(PropertyInfo)
GetSetMethod(PropertyInfo, Boolean)