internal static Func <IDataReader, TModel> GetMapper <TModel>(IDataReader reader)
{
string cacheKey = GetCacheKey <TModel>();
Delegate mapper;
if (ModelMappers.TryGetValue(cacheKey, out mapper))
{
return(mapper as Func <IDataReader, TModel>);
}
var m = new DynamicMethod(string.Format("__model_mapper_{0}", ModelMappers.Count), typeof(TModel), new[] { typeof(IDataReader) }, true);
var il = m.GetILGenerator();
il.DeclareLocal(typeof(TModel));
var ctor = typeof(TModel).GetConstructor(Type.EmptyTypes);
il.Emit(OpCodes.Newobj, ctor);
il.Emit(OpCodes.Stloc_0);
var getValue = typeof(IDataRecord).GetMethod("GetValue", new Type[] { typeof(int) });
for (int i = 0; i < reader.FieldCount; i++)
{
var sourceType = reader.GetFieldType(i);
var sourceName = reader.GetName(i);
var outputProperty =
(from p in typeof(TModel).GetProperties(BindingFlags.Public | BindingFlags.Instance)
where SqlGenerationUtility.GetColumnName(p) == sourceName &&
p.PropertyType == sourceType
select p).FirstOrDefault();
if (outputProperty == null)
{
continue;
}
MethodInfo setValue = outputProperty.GetSetMethod();
il.Emit(OpCodes.Ldloc_0);
il.Emit(OpCodes.Ldarg_0);
il.Emit(OpCodes.Ldc_I4, i);
il.Emit(OpCodes.Callvirt, getValue);
il.Emit(OpCodes.Unbox_Any, sourceType);
il.Emit(OpCodes.Callvirt, setValue);
}
il.Emit(OpCodes.Ldloc_0);
il.Emit(OpCodes.Ret);
TestShowVisualizer(m);
var @delegate = m.CreateDelegate(typeof(Func <IDataReader, TModel>));
ModelMappers[cacheKey] = @delegate;
return(@delegate as Func <IDataReader, TModel>);
}
private static IEnumerable <Tuple <MemberInfo, string> > GetColumnInformationForModel <TModel>()
{
string cacheKey = GetCacheKey <TModel>();
List <Tuple <MemberInfo, string> > columnNames;
if (ColumnNames.TryGetValue(cacheKey, out columnNames))
{
return(columnNames);
}
var modelProperties = typeof(TModel).GetProperties(BindingFlags.Public | BindingFlags.Instance);
columnNames = (from p in modelProperties
select new Tuple <MemberInfo, string>(p, SqlGenerationUtility.GetColumnName(p))).ToList();
ColumnNames[cacheKey] = columnNames;
return(columnNames);
}
