Dynamically create types and attributes-go

Using system;

Using system. reflection;

Using system. reflection. emit;

/// <Summary>

/// Create a dynamic type and add definitions for each public attribute

/// </Summary>

Public class dynamictypebuilder

{

Typebuilder TB;

/// <Summary>

/// Constructor

/// </Summary>

/// <Param name = "typenm"> name of the dynamic type </param>

Public dynamictypebuilder (string typenm)

{

// In Silverlight, assemblybuilderaccess does not have runandsave

Assemblybuilder AB = appdomain. currentdomain. definedynamicassembly (

New assemblyname ("tempassembly"), assemblybuilderaccess. Run );

 

Modulebuilder MB = AB. definedynamicmodule ("tempmodule ");

This. TB = Mb. definetype (typenm, typeattributes. Public );

}

/// <Summary>

/// Add a public read/write attribute and create a private field named propertynm + "field"

/// </Summary>

/// <Param name = "propertynm"> </param>

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

Public void appendpublicproperty (string propertynm, type)

{

This. appendpublicproperty (propertynm, type, true, true );

}

/// <Summary>

/// Add a public attribute and create a private field named propertynm + "field ".

/// </Summary>

/// <Param name = "propertynm"> </param>

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

/// <Param name = "canget"> whether to implement getter </param>

/// <Param name = "canset"> whether to implement setter </param>

Public void appendpublicproperty (string propertynm, type, bool canget, bool canset)

{

Fieldbuilder field = This. TB. definefield (string. Format ("{0} field", propertynm), type, fieldattributes. Private );

 

Propertybuilder property = Tb. defineproperty (propertynm, propertyattributes. hasdefault, type, null );

 

Methodattributes getsetattr = methodattributes. Public | methodattributes. specialname | methodattributes. hidebysig;

 

If (canget)

{

Methodbuilder getaccessor = Tb. definemethod (string. Format ("Get _ {0}", propertynm), getsetattr, type, type. emptytypes );

Ilgenerator getil = getaccessor. getilgenerator ();

# Region write the Il code

// Follow the instructions in the Il code and cannot run

//. Method public hidebysig specialname instance int32

// Get_a () cel managed

//{

/// Code size 12 (0xc)

//. Maxstack 1

//. Locals Init ([0] int32 CS $1 $0000)

// Il_0000: NOP

// Il_0001: ldarg.0

// Il_0002: ld1_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

 

// Follow the above il code and cannot run:

// Label getbrslabel = getil. definelabel ();

// Getil. emit (Opcodes. Nop );

// Getil. emit (Opcodes. ldarg_0 );

// Getil. emit (Opcodes. lddes, 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

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

// Field value on the stack.

Getil. emit (Opcodes. ldarg_0 );

Getil. emit (Opcodes. lddes, field );

Getil. emit (Opcodes. Ret );

Property. setgetmethod (getaccessor );

}

 

If (canset)

{

Methodbuilder setaccessor = Tb. definemethod (string. Format ("SET _ {0}", propertynm), getsetattr, null, new type [] {type });

Setaccessor. defineparameter (1, parameterattributes. None, "value ");

Ilgenerator setil = setaccessor. getilgenerator ();

// Load the instance and then the numeric argument, then store

// Argument in the field.

Setil. emit (Opcodes. ldarg_0 );

Setil. emit (Opcodes. ldarg_1 );

Setil. emit (Opcodes. stdes, field );

Setil. emit (Opcodes. Ret );

Property. setsetmethod (setaccessor );

}

}

/// <Summary>

/// Call this method after each public attribute is added to define and load the dynamic type,

/// Later, the dynamic type can be instantiated through activator. createinstance ().

/// </Summary>

/// <Returns> </returns>

Public type createdynamictype ()

{

Return this. TB. createtype ();

}

}