用于创建实现 System.ComponentModel.INotifyPropertyChanged 接口的动态类型，并添加各个 public 属性的定义

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

/// <summary>

/// 用于创建实现 System.ComponentModel.INotifyPropertyChanged 接口的动态类型，并添加各个 public 属性的定义

/// </summary>

public class DynamicINotifyPropertyChangedTypeBuilder

{

/// <summary>

/// 用于在导出程序集至硬盘时使用（要求AssemblyBuilderAccess.RunAndSave），不过在 Silverlight 中不能使用

/// </summary>

AssemblyBuilder ab;

TypeBuilder tb;

/// <summary>

/// 用于在调用 RaisePropertyChanged() 时使用

/// </summary>

MethodBuilder raiseEventMB;

/// <summary>

/// 构造函数

/// </summary>

/// <param name="typeNm">动态类型的名称</param>

public DynamicINotifyPropertyChangedTypeBuilder(string typeNm)

{

this.ab = AppDomain.CurrentDomain.DefineDynamicAssembly(

new AssemblyName("TempAssembly"),AssemblyBuilderAccess.RunAndSave);

ModuleBuilder mb = ab.DefineDynamicModule("NotifyPropertyChangedobject","TempAssembly.dll");

// Silverlight 或者不使用 AssemblyBuilderAccess.RunAndSave 的写法

//this.ab = AppDomain.CurrentDomain.DefineDynamicAssembly(

// new AssemblyName("TempAssembly"),AssemblyBuilderAccess.Run);

//ModuleBuilder mb = ab.DefineDynamicModule("NotifyPropertyChangedobject");

this.tb = mb.DefineType(typeNm,TypeAttributes.Public | TypeAttributes.BeforeFieldInit);

this.ImplementationInterface();

}

/// <summary>

/// 用于生成实现 System.ComponentModel.INotifyPropertyChanged 的IL代码

/// </summary>

void ImplementationInterface()

{

// 实现接口

this.tb.AddInterfaceImplementation(typeof(System.ComponentModel.INotifyPropertyChanged));

// 事件类型

Type eventType = typeof(System.ComponentModel.PropertyChangedEventHandler);

// IL代码中生成了一个与事件同名的私有字段

FieldBuilder eventField = this.tb.DefineField("PropertyChanged",eventType,FieldAttributes.Private);

// 定义事件

EventBuilder eb = this.tb.DefineEvent("PropertyChanged",EventAttributes.None,eventType);

#region 生成 add_PropertyChanged 和 remove_PropertyChanged

// 注意add_PropertyChanged 和 remove_PropertyChanged 这两个事件要求 MethodAttributes.HideBySig | MethodAttributes.NewSlot | MethodAttributes.Final | MethodAttributes.SpecialName | MethodAttributes.Virtual 等属性

MethodBuilder addEventMB = this.tb.DefineMethod("add_PropertyChanged",

null,new Type[] { eventType });

//注意在使用事件时，使用的是+=操作，但在IL代码中应该使用Delegate.Combine方法

ILGenerator addEventIL = addEventMB.GetILGenerator();

addEventIL.Emit(OpCodes.Ldarg_0);

addEventIL.Emit(OpCodes.Ldfld,eventField);

addEventIL.Emit(OpCodes.Ldarg_1);

addEventIL.Emit(OpCodes.Call,typeof(Delegate).getmethod("Combine",new Type[] { eventType,eventType }));

//返回的是Delegate类型，所以需要进行转换

addEventIL.Emit(OpCodes.Castclass,eventType);

addEventIL.Emit(OpCodes.Stfld,eventField);

addEventIL.Emit(OpCodes.Ret);

eb.SetAddOnMethod(addEventMB);

MethodBuilder removeEventMB = this.tb.DefineMethod("remove_PropertyChanged",

null,new Type[] { eventType });

//注意在使用事件时，使用的是-=操作，但在IL代码中应该使用Delegate.Remove方法

ILGenerator removeEventIL = removeEventMB.GetILGenerator();

removeEventIL.Emit(OpCodes.Ldarg_0);

removeEventIL.Emit(OpCodes.Ldfld,eventField);

removeEventIL.Emit(OpCodes.Ldarg_1);

removeEventIL.Emit(OpCodes.Call,typeof(Delegate).getmethod("Remove",eventType }));

removeEventIL.Emit(OpCodes.Castclass,eventType);

removeEventIL.Emit(OpCodes.Stfld,eventField);

removeEventIL.Emit(OpCodes.Ret);

eb.SetRemoveOnMethod(removeEventMB);

#endregion

#region 生成 RaisePropertyChanged

//要生成的代码原型（为了便于测试故意声明为 public）：

//protected void RaisePropertyChanged(string propertyName)

//{

// PropertyChangedEventHandler temp = this.PropertyChanged;

// if (temp != null)

// {

// PropertyChangedEventArgs arg = new PropertyChangedEventArgs(propertyName);

// temp(this,arg);

// }

//}

// IL代码为：

//.method public hidebysig instance void NotifyPropertyChanged(string propertyName) cil managed

//{

// // Code size 35 (0x23)

// .maxstack 3

// .locals init ([0] class [System]System.ComponentModel.PropertyChangedEventHandler temp,

// [1] class [System]System.ComponentModel.PropertyChangedEventArgs arg,

// [2] bool CS$4$0000)

// IL_0000: nop

// IL_0001: ldarg.0

// IL_0002: ldfld class [System]System.ComponentModel.PropertyChangedEventHandler WpfApplication2.Person::PropertyChanged

// IL_0007: stloc.0

// IL_0008: ldloc.0

// IL_0009: ldnull

// IL_000a: ceq

// IL_000c: stloc.2

// IL_000d: ldloc.2

// IL_000e: brtrue.s IL_0022

// IL_0010: nop

// IL_0011: ldarg.1

// IL_0012: newobj instance void [System]System.ComponentModel.PropertyChangedEventArgs::.ctor(string)

// IL_0017: stloc.1

// IL_0018: ldloc.0

// IL_0019: ldarg.0

// IL_001a: ldloc.1

// IL_001b: callvirt instance void [System]System.ComponentModel.PropertyChangedEventHandler::Invoke(object,

// class [System]System.ComponentModel.PropertyChangedEventArgs)

// IL_0020: nop

// IL_0021: nop

// IL_0022: ret

//} // end of method Person::NotifyPropertyChanged

//下述的 ILGenerator 所生成的 IL 代码为：

//.method public hidebysig instance void RaisePropertyChanged(string propertyName) cil managed

//{

// // Code size 26 (0x1a)

// .maxstack 3

// .locals init (class [System]System.ComponentModel.PropertyChangedEventHandler V_0,

// class [System]System.ComponentModel.PropertyChangedEventArgs V_1)

// IL_0000: ldarg.0

// IL_0001: ldfld class [System]System.ComponentModel.PropertyChangedEventHandler LB::PropertyChanged

// IL_0006: stloc.0

// IL_0007: ldloc.0

// IL_0008: brfalse.s IL_0019

// IL_000a: ldarg.1

// IL_000b: newobj instance void [System]System.ComponentModel.PropertyChangedEventArgs::.ctor(string)

// IL_0010: stloc.1

// IL_0011: ldloc.0

// IL_0012: ldarg.0

// IL_0013: ldloc.1

// IL_0014: callvirt instance void [System]System.ComponentModel.PropertyChangedEventHandler::Invoke(object,

// class [System]System.ComponentModel.PropertyChangedEventArgs)

// IL_0019: ret

//} // end of method LB::RaisePropertyChanged

this.raiseEventMB = this.tb.DefineMethod("RaisePropertyChanged",MethodAttributes.Family | MethodAttributes.HideBySig,null,new Type[] { typeof(String) });

raiseEventMB.DefineParameter(1,Parameterattributes.None,"propertyName");

ILGenerator raiseEventIL = raiseEventMB.GetILGenerator();

// 定义 temp 和 arg 两个临时变量

LocalBuilder temp = raiseEventIL.DeclareLocal(eventType);

LocalBuilder arg = raiseEventIL.DeclareLocal(typeof(System.ComponentModel.PropertyChangedEventArgs));

Label returnLabel = raiseEventIL.DefineLabel();

//System.ComponentModel.PropertyChangedEventHandler temp = this.PropertyChanged;

raiseEventIL.Emit(OpCodes.Ldarg_0);

raiseEventIL.Emit(OpCodes.Ldfld,eventField);

raiseEventIL.Emit(OpCodes.Stloc_0);

//if (temp == null) return

raiseEventIL.Emit(OpCodes.Ldloc_0);

raiseEventIL.Emit(OpCodes.Brfalse_S,returnLabel);

//System.ComponentModel.PropertyChangedEventArgs arg = new PropertyChangedEventArgs(propertyName);

raiseEventIL.Emit(OpCodes.Ldarg_1);

raiseEventIL.Emit(OpCodes.Newobj,typeof(System.ComponentModel.PropertyChangedEventArgs).GetConstructor(new Type[] { typeof(String) }));

raiseEventIL.Emit(OpCodes.Stloc_1);

//temp(this,arg);

raiseEventIL.Emit(OpCodes.Ldloc_0);

raiseEventIL.Emit(OpCodes.Ldarg_0);

raiseEventIL.Emit(OpCodes.Ldloc_1);

raiseEventIL.Emit(OpCodes.Callvirt,eventType.getmethod("Invoke"));

raiseEventIL.MarkLabel(returnLabel);

raiseEventIL.Emit(OpCodes.Ret);

#endregion

#region 生成 RaisePropertyChanged

//要生成的代码原型（为了便于测试故意声明为 public）：

//public void RaisePropertyChanged(string propertyName)

//{

// if (PropertyChanged != null)

// {

// PropertyChanged(this,new PropertyChangedEventArgs(propertyName));

// }

//}

//IL代码为：

//.method public hidebysig instance void NotifyPropertyChanged(string propertyName) cil managed

//{

// // Code size 36 (0x24)

// .maxstack 4

// .locals init ([0] bool CS$4$0000)

// IL_0000: nop

// IL_0001: ldarg.0

// IL_0002: ldfld class [System]System.ComponentModel.PropertyChangedEventHandler WpfApplication2.Person::PropertyChanged

// IL_0007: ldnull

// IL_0008: ceq

// IL_000a: stloc.0

// IL_000b: ldloc.0

// IL_000c: brtrue.s IL_0023

// IL_000e: nop

// IL_000f: ldarg.0

// IL_0010: ldfld class [System]System.ComponentModel.PropertyChangedEventHandler WpfApplication2.Person::PropertyChanged

// IL_0015: ldarg.0

// IL_0016: ldarg.1

// IL_0017: newobj instance void [System]System.ComponentModel.PropertyChangedEventArgs::.ctor(string)

// IL_001c: callvirt instance void [System]System.ComponentModel.PropertyChangedEventHandler::Invoke(object,

// class [System]System.ComponentModel.PropertyChangedEventArgs)

// IL_0021: nop

// IL_0022: nop

// IL_0023: ret

//} // end of method Person::NotifyPropertyChanged

//this.raiseEventMB = this.tb.DefineMethod("RaisePropertyChanged",MethodAttributes.Public | MethodAttributes.HideBySig,null,new Type[] { typeof(String) });

//raiseEventMB.DefineParameter(1,Parameterattributes.None,"propertyName");

//ILGenerator raiseEventIL = raiseEventMB.GetILGenerator();

//Label returnLabel = raiseEventIL.DefineLabel();

// 完全按照上面 IL 代码的写法，不能运行

//raiseEventIL.Emit(OpCodes.nop);

//raiseEventIL.Emit(OpCodes.Ldarg_0);

//raiseEventIL.Emit(OpCodes.Ldfld,eventField);

//raiseEventIL.Emit(OpCodes.Ldnull);

//raiseEventIL.Emit(OpCodes.Ceq);

//raiseEventIL.Emit(OpCodes.Stloc_0);

//raiseEventIL.Emit(OpCodes.Ldloc_0);

//raiseEventIL.Emit(OpCodes.Brtrue_S, returnLabel );

//raiseEventIL.Emit(OpCodes.nop);

//raiseEventIL.Emit(OpCodes.Ldarg_0);

//raiseEventIL.Emit(OpCodes.Ldfld,eventField);

//raiseEventIL.Emit(OpCodes.Ldarg_0);

//raiseEventIL.Emit(OpCodes.Ldarg_1);

//raiseEventIL.Emit(OpCodes.Newobj,typeof(System.ComponentModel.PropertyChangedEventArgs).GetConstructor(new Type[] { typeof(String) }));

//raiseEventIL.Emit(OpCodes.Callvirt,eventType.getmethod("Invoke"));

//raiseEventIL.Emit(OpCodes.nop);

//raiseEventIL.MarkLabel(returnLabel);

//raiseEventIL.Emit(OpCodes.Ret);

#endregion

}

/// <summary>

/// 添加一个public的可读写属性，并且会创建对应的名为 propertyNm + "Field" 的私有字段。

/// 对于 setter 则会引发 PropertyChanged 事件

/// </summary>

/// <param name="propertyNm"></param>

/// <param name="type"></param>

public void AppendPublicPropertyByRaisingPropertyChanging(string propertyNm,Type type)

{

FieldBuilder field = this.tb.DefineField(string.Format("{0}Field",propertyNm),type,FieldAttributes.Private);

PropertyBuilder property = tb.DefineProperty(propertyNm,PropertyAttributes.HasDefault,null);

MethodAttributes getSetAttr = MethodAttributes.Public | MethodAttributes.SpecialName | MethodAttributes.HideBySig;

MethodBuilder getAccessor = tb.DefineMethod(string.Format("get_{0}",getSetAttr,Type.EmptyTypes);

ILGenerator getIL = getAccessor.GetILGenerator();

#region 按照 IL 代码的写法

// 按照 IL 代码的写法，不能运行

//.method public hidebysig specialname instance int32

// get_A() cil managed

//{

// // Code size 12 (0xc)

// .maxstack 1

// .locals init ([0] int32 CS$1$0000)

// IL_0000: nop

// IL_0001: ldarg.0

// IL_0002: ldfld int32 WpfApplication2.Person::AField

// IL_0007: stloc.0

// IL_0008: br.s IL_000a

// IL_000a: ldloc.0

// IL_000b: ret

//} // end of method Person::get_A

// 按照上面 IL 代码的写法，不能运行：

//Label getBrsLabel = getIL.DefineLabel();

//getIL.Emit(OpCodes.nop);

//getIL.Emit(OpCodes.Ldarg_0);

//getIL.Emit(OpCodes.Ldfld,field);

//getIL.Emit(OpCodes.Stloc_0);

//getIL.Emit(OpCodes.Br_S,getBrsLabel);

//getIL.MarkLabel(getBrsLabel);

//getIL.Emit(OpCodes.Ldloc_0);

//getIL.Emit(OpCodes.Ret);

#endregion

// For an instance property,argument default is the instance. Load the

// instance,then load the private field and return,leaving the

// field value on the stack.

getIL.Emit(OpCodes.Ldarg_0);

getIL.Emit(OpCodes.Ldfld,field);

getIL.Emit(OpCodes.Ret);

property.Setgetmethod(getAccessor);

MethodBuilder setAccessor = tb.DefineMethod(string.Format("set_{0}",new Type[] { type });

setAccessor.DefineParameter(1,"value");

ILGenerator setIL = setAccessor.GetILGenerator();

setIL.Emit(OpCodes.nop);

setIL.Emit(OpCodes.Ldarg_0);

setIL.Emit(OpCodes.Ldarg_1);

setIL.Emit(OpCodes.Stfld,field);

setIL.Emit(OpCodes.Ldarg_0);

setIL.Emit(OpCodes.Ldstr,propertyNm);

setIL.Emit(OpCodes.Call,this.raiseEventMB);

setIL.Emit(OpCodes.nop);

setIL.Emit(OpCodes.Ret);

property.SetSetMethod(setAccessor);

}

/// <summary>

/// 在添加完各个 public 属性之后，调用此方法以完成对动态类型的定义并加载之，

/// 此后通过 Activator.CreateInstance() 便可实例化动态类型

/// </summary>

/// <returns></returns>

public Type CreateDynamicType()

{

return this.tb.CreateType();

}

/// <summary>

/// 保存程序集至硬盘，Silverlight 中无此功能

/// </summary>

public void Save()

{

this.ab.Save("TempAssembly.dll");

}

用于创建实现 System.ComponentModel.INotifyPropertyChanged 接口的动态类型，并添加各个 public 属性的定义

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