public static Action <object, IDataReader, int> CreateSetValueFromReaderDelegate(MemberInfo member)
{
Action <object, IDataReader, int> del = null;
DynamicMethod dm = new DynamicMethod("SetValueFromReader_" + Guid.NewGuid().ToString("N"), null, new Type[] { typeof(object), typeof(IDataReader), typeof(int) }, true);
ILGenerator il = dm.GetILGenerator();
il.Emit(OpCodes.Ldarg_S, 0); //将第一个参数 object 对象加载到栈顶
il.Emit(OpCodes.Castclass, member.DeclaringType); //将 object 对象转换为强类型对象 此时栈顶为强类型的对象
var readerMethod = DataReaderConstant.GetReaderMethod(member.GetMemberType());
//ordinal
il.Emit(OpCodes.Ldarg_S, 1); //加载参数DataReader
il.Emit(OpCodes.Ldarg_S, 2); //加载 read ordinal
il.EmitCall(OpCodes.Call, readerMethod, null); //调用对应的 readerMethod 得到 value reader.Getxx(ordinal); 此时栈顶为 value
EmitHelper.SetValueIL(il, member); // object.XX = value; 此时栈顶为空
il.Emit(OpCodes.Ret); // 即可 return
del = (Action <object, IDataReader, int>)dm.CreateDelegate(typeof(Action <object, IDataReader, int>));
return(del);
}
public static Type CreateMRMType(MemberInfo member)
{
if (member.MemberType != MemberTypes.Property && member.MemberType != MemberTypes.Field)
{
throw new NotSupportedException();
}
Type entityType = member.DeclaringType;
TypeInfo typeInfo = entityType.GetTypeInfo();
Assembly assembly = typeInfo.Assembly;
ModuleBuilder moduleBuilder;
if (!_moduleBuilders.TryGetValue(assembly, out moduleBuilder))
{
lock (assembly)
{
if (!_moduleBuilders.TryGetValue(assembly, out moduleBuilder))
{
var assemblyName =
new AssemblyName(String.Format(CultureInfo.InvariantCulture, "ChloeMRMs-{0}", assembly.FullName));
assemblyName.Version = new Version(1, 0, 0, 0);
AssemblyBuilder assemblyBuilder = AssemblyBuilder.DefineDynamicAssembly(assemblyName, AssemblyBuilderAccess.Run);
moduleBuilder = assemblyBuilder.DefineDynamicModule("ChloeMRMModule");
_moduleBuilders.Add(assembly, moduleBuilder);
}
}
}
TypeAttributes typeAttributes = TypeAttributes.Class | TypeAttributes.NotPublic | TypeAttributes.Sealed;
TypeBuilder tb = moduleBuilder.DefineType(string.Format("Chloe.Core.Mapper.MRMs.{0}_{1}_{2}", entityType.Name, member.Name, Guid.NewGuid().ToString("N") + System.Threading.Interlocked.Increment(ref _sequenceNumber).ToString()), typeAttributes, null, new Type[] { typeof(IMRM) });
tb.DefineDefaultConstructor(MethodAttributes.Public | MethodAttributes.SpecialName);
MethodBuilder methodBuilder = tb.DefineMethod("Map", MethodAttributes.Public | MethodAttributes.Virtual, CallingConventions.HasThis, typeof(void), new Type[] { typeof(object), typeof(IDataReader), typeof(int) });
ILGenerator il = methodBuilder.GetILGenerator();
int parameStartIndex = 1;
il.Emit(OpCodes.Ldarg_S, parameStartIndex); //将第一个参数 object 对象加载到栈顶
il.Emit(OpCodes.Castclass, member.DeclaringType); //将 object 对象转换为强类型对象 此时栈顶为强类型的对象
var readerMethod = DataReaderConstant.GetReaderMethod(ReflectionExtension.GetPropertyOrFieldType(member));
//ordinal
il.Emit(OpCodes.Ldarg_S, parameStartIndex + 1); //加载参数DataReader
il.Emit(OpCodes.Ldarg_S, parameStartIndex + 2); //加载 read ordinal
il.EmitCall(OpCodes.Call, readerMethod, null); //调用对应的 readerMethod 得到 value reader.Getxx(ordinal); 此时栈顶为 value
EmitHelper.SetValueIL(il, member); // object.XX = value; 此时栈顶为空
il.Emit(OpCodes.Ret); // 即可 return
Type t = tb.CreateTypeInfo().AsType();
return(t);
}
