PropertyBuilder Class

Definition

Namespace:

System.Reflection.Emit

Assembly:

System.Reflection.Emit.dll

Source:

PropertyBuilder.cs

Defines the properties for a type.

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

public abstract class PropertyBuilder : System.Reflection.PropertyInfo

type PropertyBuilder = class
    inherit PropertyInfo

Public MustInherit Class PropertyBuilder
Inherits PropertyInfo

Inheritance

Object

MemberInfo

PropertyInfo

PropertyBuilder

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' 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' 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'.
' -------------------

Remarks

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

Constructors

PropertyBuilder()

Initializes a new instance of the PropertyBuilder class.

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.
CustomAttributes	Gets a collection that contains this member's custom attributes. (Inherited from MemberInfo)
DeclaringType	Gets the class that declares this member.
GetMethod	Gets the get accessor for this property. (Inherited from PropertyInfo)
IsCollectible	Gets a value that indicates whether this MemberInfo object is part of an assembly held in a collectible AssemblyLoadContext. (Inherited from MemberInfo)
IsSpecialName	Gets a value indicating whether the property is the special name. (Inherited from PropertyInfo)
MemberType	Gets a MemberTypes value indicating that this member is a property. (Inherited from PropertyInfo)
MetadataToken	Gets a value that identifies a metadata element. (Inherited from MemberInfo)
Module	Gets the module in which the type that declares the current property is being defined.
Name	Gets the name of this member.
PropertyType	Gets the type of the field of this property.
ReflectedType	Gets the class object that was used to obtain this instance of MemberInfo.
SetMethod	Gets the set accessor for this property. (Inherited from PropertyInfo)

Methods

AddOtherMethod(MethodBuilder)	Adds one of the other methods associated with this property.
AddOtherMethodCore(MethodBuilder)	When overridden in a derived class, adds one of the other methods associated with this property.
Equals(Object)	Returns a value that indicates whether this instance is equal to a specified object. (Inherited from PropertyInfo)
GetAccessors()	Returns an array whose elements reflect the public get and set accessors of the property reflected by the current instance. (Inherited from PropertyInfo)
GetAccessors(Boolean)	Returns an array of the public and non-public get and set accessors on this property.
GetConstantValue()	Returns a literal value associated with the property by a compiler. (Inherited from PropertyInfo)
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.
GetCustomAttributesData()	Returns a list of CustomAttributeData objects representing data about the attributes that have been applied to the target member. (Inherited from MemberInfo)
GetGetMethod()	Returns the public get accessor for this property. (Inherited from PropertyInfo)
GetGetMethod(Boolean)	Returns the public and non-public get accessor for this property.
GetHashCode()	Returns the hash code for this instance. (Inherited from PropertyInfo)
GetIndexParameters()	Returns an array of all the index parameters for the property.
GetModifiedPropertyType()	Gets the modified type of this property object. (Inherited from PropertyInfo)
GetOptionalCustomModifiers()	Returns an array of types representing the optional custom modifiers of the property. (Inherited from PropertyInfo)
GetRawConstantValue()	Returns a literal value associated with the property by a compiler. (Inherited from PropertyInfo)
GetRequiredCustomModifiers()	Returns an array of types representing the required custom modifiers of the property. (Inherited from PropertyInfo)
GetSetMethod()	Returns the public set accessor for this property. (Inherited from PropertyInfo)
GetSetMethod(Boolean)	Returns the set accessor for this property.
GetType()	Discovers the attributes of a property and provides access to property metadata. (Inherited from PropertyInfo)
GetValue(Object)	Returns the property value of a specified object. (Inherited from PropertyInfo)
GetValue(Object, BindingFlags, Binder, Object[], CultureInfo)	Gets the value of a property having the specified binding, index, and CultureInfo.
GetValue(Object, Object[])	Gets the value of the indexed property by calling the property's getter method.
HasSameMetadataDefinitionAs(MemberInfo)	(Inherited from MemberInfo)
IsDefined(Type, Boolean)	Indicates whether one or more instance of attributeType is defined on this property.
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
SetConstant(Object)	Sets the default value of this property.
SetConstantCore(Object)	When overridden in a derived class, sets the default value of this property.
SetCustomAttribute(ConstructorInfo, Byte[])	Set a custom attribute using a specified custom attribute blob.
SetCustomAttribute(CustomAttributeBuilder)	Set 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.
SetGetMethod(MethodBuilder)	Sets the method that gets the property value.
SetGetMethodCore(MethodBuilder)	When overridden in a derived class, sets the method that gets the property value.
SetSetMethod(MethodBuilder)	Sets the method that sets the property value.
SetSetMethodCore(MethodBuilder)	When overridden in a derived class, sets the method that sets the property value.
SetValue(Object, Object)	Sets the property value of a specified object. (Inherited from PropertyInfo)
SetValue(Object, Object, BindingFlags, Binder, Object[], CultureInfo)	Sets the property value for the given object to the given value.
SetValue(Object, Object, Object[])	Sets the value of the property with optional index values for index properties.
ToString()	Returns a string that represents the current object. (Inherited from Object)

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.
GetAccessors(PropertyInfo)
GetAccessors(PropertyInfo, Boolean)
GetGetMethod(PropertyInfo)
GetGetMethod(PropertyInfo, Boolean)
GetSetMethod(PropertyInfo)
GetSetMethod(PropertyInfo, Boolean)