public static DataTableEntityBuilder <TEntity> CreateBuilder(DataRow dataRecord)
{
DataTableEntityBuilder <TEntity> dynamicBuilder = new DataTableEntityBuilder <TEntity>();
DynamicMethod method = new DynamicMethod("DynamicCreateEntity", typeof(TEntity), new Type[] { typeof(DataRow) }, typeof(TEntity), true);
ILGenerator generator = method.GetILGenerator();
LocalBuilder result = generator.DeclareLocal(typeof(TEntity));
generator.Emit(OpCodes.Newobj, typeof(TEntity).GetConstructor(Type.EmptyTypes));
generator.Emit(OpCodes.Stloc, result);
for (int i = 0; i < dataRecord.ItemArray.Length; i++)
{
PropertyInfo propertyInfo = typeof(TEntity).GetProperty(dataRecord.Table.Columns[i].ColumnName);
Label endIfLabel = generator.DefineLabel();
if (propertyInfo != null && propertyInfo.GetSetMethod() != null)
{
generator.Emit(OpCodes.Ldarg_0);
generator.Emit(OpCodes.Ldc_I4, i);
generator.Emit(OpCodes.Callvirt, isDBNullMethod);
generator.Emit(OpCodes.Brtrue, endIfLabel);
generator.Emit(OpCodes.Ldloc, result);
generator.Emit(OpCodes.Ldarg_0);
generator.Emit(OpCodes.Ldc_I4, i);
generator.Emit(OpCodes.Callvirt, getValueMethod);
generator.Emit(OpCodes.Unbox_Any, propertyInfo.PropertyType);
generator.Emit(OpCodes.Callvirt, propertyInfo.GetSetMethod());
generator.MarkLabel(endIfLabel);
}
}
generator.Emit(OpCodes.Ldloc, result);
generator.Emit(OpCodes.Ret);
dynamicBuilder.handler = (Load)method.CreateDelegate(typeof(Load));
return(dynamicBuilder);
}
//最快和直接循环差不多
public static List <TResult> ToList <TResult>(this DataTable dt) where TResult : class, new()
{
List <TResult> list = new List <TResult>();
if (dt == null)
{
return(list);
}
DataTableEntityBuilder <TResult> eblist = DataTableEntityBuilder <TResult> .CreateBuilder(dt.Rows[0]);
foreach (DataRow info in dt.Rows)
{
list.Add(eblist.Build(info));
}
dt.Dispose(); dt = null;
return(list);
}
