代碼 ///?<summary>
///?DataTransfer?的摘要說明
///?</summary>
public?static?class?DataTransfer
{
????///?<summary>
????///?datatable?to?list
????///?</summary>
????///?<typeparam?name="T"></typeparam>
????///?<param?name="dt"></param>
????///?<returns></returns>
????public?static?List<T>?ToList<T>(DataTable?dt)
????{
????????List<T>?list?=?new?List<T>();
????????if?(dt?==?null)?return?list;
????????if?(dt.Rows.Count?<?1)?return?list;
????????DataTableEntityBuilder<T>?eblist?=?DataTableEntityBuilder<T>.CreateBuilder(dt.Rows[0]);
????????foreach?(DataRow?info?in?dt.Rows)
????????????list.Add(eblist.Build(info));
????????dt.Dispose();
????????dt?=?null;
????????return?list;
????}

????///?<summary>
????///?builder
????///?</summary>
????///?<typeparam?name="T"></typeparam>
????public?class?DataTableEntityBuilder<T>
????{
????????private?static?readonly?MethodInfo?getValueMethod?=?typeof(DataRow).GetMethod("get_Item",?new?Type[]?{?typeof(int)?});
????????private?static?readonly?MethodInfo?isDBNullMethod?=?typeof(DataRow).GetMethod("IsNull",?new?Type[]?{?typeof(int)?});
????????private?delegate?T?Load(DataRow?dataRecord);

????????private?Load?handler;
????????private?DataTableEntityBuilder()?{?}

????????public?T?Build(DataRow?dataRecord)
????????{
????????????return?handler(dataRecord);
????????}

????????public?static?DataTableEntityBuilder<T>?CreateBuilder(DataRow?dataRow)
????????{
????????????DataTableEntityBuilder<T>?dynamicBuilder?=?new?DataTableEntityBuilder<T>();
????????????DynamicMethod?method?=?new?DynamicMethod("DynamicCreateEntity",?typeof(T),?new?Type[]?{?typeof(DataRow)?},?typeof(T),?true);
????????????ILGenerator?generator?=?method.GetILGenerator();
????????????LocalBuilder?result?=?generator.DeclareLocal(typeof(T));
????????????generator.Emit(OpCodes.Newobj,?typeof(T).GetConstructor(Type.EmptyTypes));
????????????generator.Emit(OpCodes.Stloc,?result);

????????????for?(int?index?=?0;?index?<?dataRow.ItemArray.Length;?index++)
????????????{
????????????????PropertyInfo?propertyInfo?=?typeof(T).GetProperty(dataRow.Table.Columns[index].ColumnName);
????????????????Label?endIfLabel?=?generator.DefineLabel();
????????????????if?(propertyInfo?!=?null?&&?propertyInfo.GetSetMethod()?!=?null)
????????????????{
????????????????????generator.Emit(OpCodes.Ldarg_0);
????????????????????generator.Emit(OpCodes.Ldc_I4,?index);
????????????????????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,?index);
????????????????????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;
????????}
????}

?

轉載于:https://www.cnblogs.com/OSoft/archive/2010/12/03/1895485.html

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