public static DynamicMethod CreateObjectToParamListMethod <TParam>(Type objType) where TParam : DbParameter
{
var listType = typeof(List <TParam>);
var instanceType = typeof(TParam);
//三个参数，第一个参数是object，第二个参数是参数符号（@,:,?），参数前缀
DynamicMethod convertMethod = new DynamicMethod("ConvertObjectToParamList" + objType.Name, listType, new Type[] { TypeUtil._ObjectType, TypeUtil._StringType, TypeUtil._StringType }, true);
ILGenerator il = convertMethod.GetILGenerator();
LocalBuilder listBuilder = il.DeclareLocal(listType);//List<T> 存储对象
il.SetDefaultObjectValue(listType, listBuilder);
LocalBuilder objBuilder = il.DeclareLocal(objType);
il.Emit(OpCodes.Ldarg_0);
il.SetObjectCastIL(objType);
il.Emit(OpCodes.Stloc, objBuilder);
LocalBuilder dbNullBuilder = il.SetDbNullIL();
List <PropertyInfo> properties = PropertyUtil.GetTypeProperties(objType);
foreach (var item in properties)
{
Label setDbNullLable = il.DefineLabel(); //设置dbnull
Label setParamLable = il.DefineLabel(); //给param赋值
Label exitLable = il.DefineLabel(); //退出
LocalBuilder paramNameBuilder = il.DeclareLocal(TypeUtil._StringType); //参数变量名字
il.Emit(OpCodes.Ldarg_1);
il.Emit(OpCodes.Ldarg_2);
il.Emit(OpCodes.Ldstr, item.Name);
il.Emit(OpCodes.Call, TypeUtil._StringType.GetMethod("Concat", new Type[] { TypeUtil._StringType, TypeUtil._StringType, TypeUtil._StringType }));
il.Emit(OpCodes.Stloc, paramNameBuilder);
LocalBuilder instanceBuilder = il.DeclareLocal(instanceType);// T 存储对象
il.SetDefaultObjectValue(instanceType, instanceBuilder);
LocalBuilder dbTypeBuilder = il.DeclareLocal(TypeUtil._DbTypeType);
il.LdcInt((int)TypeUtil.Type2DbType(item.PropertyType));//数据库类型
il.Emit(OpCodes.Stloc, dbTypeBuilder);
//设置dbType
il.Emit(OpCodes.Ldloc, instanceBuilder);
il.Emit(OpCodes.Ldloc, dbTypeBuilder);
il.Emit(OpCodes.Callvirt, instanceType.GetMethod("set_DbType", new Type[] { TypeUtil._DbTypeType }));
//设置ParameterName
il.Emit(OpCodes.Ldloc, instanceBuilder);
il.Emit(OpCodes.Ldloc, paramNameBuilder);
il.Emit(OpCodes.Callvirt, instanceType.GetMethod("set_ParameterName", new Type[] { TypeUtil._StringType }));
il.Emit(OpCodes.Nop);
LocalBuilder dbValueBuilder = il.DeclareLocal(TypeUtil._ObjectType);
var getMethod = item.GetGetMethod(true);
if (getMethod == null)
{
il.Emit(OpCodes.Br_S, setDbNullLable);
}
else
{
il.Emit(OpCodes.Ldloc, objBuilder);
if (item.DeclaringType.IsValueType && Nullable.GetUnderlyingType(item.DeclaringType) == null)
{
var t = il.DeclareLocal(item.DeclaringType);
il.Emit(OpCodes.Stloc, t);
il.Emit(OpCodes.Ldloca_S, t);
}
if (item.DeclaringType.IsValueType)
{
il.Emit(OpCodes.Call, getMethod);
}
else
{
il.Emit(OpCodes.Callvirt, getMethod);
}
if (item.PropertyType.IsValueType)
{
il.Emit(OpCodes.Box, item.PropertyType);
if (item.PropertyType.IsEnum)
{
il.Emit(OpCodes.Ldstr, "d");
il.Emit(OpCodes.Call, typeof(Enum).GetMethod("ToString", new Type[] { TypeUtil._StringType }));
}
}
il.Emit(OpCodes.Stloc, dbValueBuilder);
il.Emit(OpCodes.Ldloc, dbValueBuilder);
il.Emit(OpCodes.Ldnull);
il.Emit(OpCodes.Beq_S, setDbNullLable);
il.Emit(OpCodes.Br_S, setParamLable);
}
il.MarkLabel(setDbNullLable);
il.Emit(OpCodes.Ldloc, dbNullBuilder);
il.Emit(OpCodes.Stloc, dbValueBuilder);
il.Emit(OpCodes.Br_S, setParamLable);
il.MarkLabel(setParamLable);
il.Emit(OpCodes.Ldloc, instanceBuilder);
il.Emit(OpCodes.Ldloc, dbValueBuilder);
il.Emit(OpCodes.Callvirt, instanceType.GetMethod("set_Value", new Type[] { TypeUtil._ObjectType }));
il.Emit(OpCodes.Ldloc, listBuilder);
il.Emit(OpCodes.Ldloc, instanceBuilder);
il.Emit(OpCodes.Call, listType.GetMethod("Add"));
}
il.Emit(OpCodes.Ldloc, listBuilder);
il.Emit(OpCodes.Ret);
return(convertMethod);
}
