Created
December 15, 2020 12:35
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dynamic type builder
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using System; | |
using System.Reflection; | |
using System.Reflection.Emit; | |
namespace TypeBuilderNamespace | |
{ | |
public static class MyTypeBuilder | |
{ | |
public static void CreateNewObject() | |
{ | |
var myType = CompileResultType(); | |
var myObject = Activator.CreateInstance(myType); | |
} | |
public static Type CompileResultType() | |
{ | |
TypeBuilder tb = GetTypeBuilder(); | |
ConstructorBuilder constructor = tb.DefineDefaultConstructor(MethodAttributes.Public | MethodAttributes.SpecialName | MethodAttributes.RTSpecialName); | |
// NOTE: assuming your list contains Field objects with fields FieldName(string) and FieldType(Type) | |
foreach (var field in yourListOfFields) | |
CreateProperty(tb, field.FieldName, field.FieldType); | |
Type objectType = tb.CreateType(); | |
return objectType; | |
} | |
private static TypeBuilder GetTypeBuilder() | |
{ | |
var typeSignature = "MyDynamicType"; | |
var an = new AssemblyName(typeSignature); | |
AssemblyBuilder assemblyBuilder = AppDomain.CurrentDomain.DefineDynamicAssembly(an, AssemblyBuilderAccess.Run); | |
ModuleBuilder moduleBuilder = assemblyBuilder.DefineDynamicModule("MainModule"); | |
TypeBuilder tb = moduleBuilder.DefineType(typeSignature, | |
TypeAttributes.Public | | |
TypeAttributes.Class | | |
TypeAttributes.AutoClass | | |
TypeAttributes.AnsiClass | | |
TypeAttributes.BeforeFieldInit | | |
TypeAttributes.AutoLayout, | |
null); | |
return tb; | |
} | |
private static void CreateProperty(TypeBuilder tb, string propertyName, Type propertyType) | |
{ | |
FieldBuilder fieldBuilder = tb.DefineField("_" + propertyName, propertyType, FieldAttributes.Private); | |
PropertyBuilder propertyBuilder = tb.DefineProperty(propertyName, PropertyAttributes.HasDefault, propertyType, null); | |
MethodBuilder getPropMthdBldr = tb.DefineMethod("get_" + propertyName, MethodAttributes.Public | MethodAttributes.SpecialName | MethodAttributes.HideBySig, propertyType, Type.EmptyTypes); | |
ILGenerator getIl = getPropMthdBldr.GetILGenerator(); | |
getIl.Emit(OpCodes.Ldarg_0); | |
getIl.Emit(OpCodes.Ldfld, fieldBuilder); | |
getIl.Emit(OpCodes.Ret); | |
MethodBuilder setPropMthdBldr = | |
tb.DefineMethod("set_" + propertyName, | |
MethodAttributes.Public | | |
MethodAttributes.SpecialName | | |
MethodAttributes.HideBySig, | |
null, new[] { propertyType }); | |
ILGenerator setIl = setPropMthdBldr.GetILGenerator(); | |
Label modifyProperty = setIl.DefineLabel(); | |
Label exitSet = setIl.DefineLabel(); | |
setIl.MarkLabel(modifyProperty); | |
setIl.Emit(OpCodes.Ldarg_0); | |
setIl.Emit(OpCodes.Ldarg_1); | |
setIl.Emit(OpCodes.Stfld, fieldBuilder); | |
setIl.Emit(OpCodes.Nop); | |
setIl.MarkLabel(exitSet); | |
setIl.Emit(OpCodes.Ret); | |
propertyBuilder.SetGetMethod(getPropMthdBldr); | |
propertyBuilder.SetSetMethod(setPropMthdBldr); | |
} | |
} |
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