asp.net项目出现 实例失败

错误:
实例失败。
说明: 执行当前 Web 请求期间，出现未处理的异常。请检查堆栈跟踪信息，以了解有关该错误以及代码中导致错误的出处的详细信息。

异常详细信息: System.InvalidOperationException: 实例失败。

源错误:


行 164: {
行 165: Console.WriteLine(e.Message);
行 166: throw e;
行 167: }
行 168:


源文件: F:\Program Files\easyMule\Incoming\asp.net与extjs开发点卡在线销售系统\Y2毕业设计\项目源码\GameCardShop\GameCardShopDAL\Auto\CardTypeService.cs 行: 166
堆栈跟踪:

[InvalidOperationException: 实例失败。]
GameCardShop.DAL.CardTypeService.GetCardTypesBySql(String safeSql) in F:\Program Files\easyMule\Incoming\asp.net与extjs开发点卡在线销售系统\Y2毕业设计\项目源码\GameCardShop\GameCardShopDAL\Auto\CardTypeService.cs:166
GameCardShop.DAL.CardTypeService.GetAllCardTypes() in F:\Program Files\easyMule\Incoming\asp.net与extjs开发点卡在线销售系统\Y2毕业设计\项目源码\GameCardShop\GameCardShopDAL\Auto\CardTypeService.cs:102
GameCardShop.BLL.CardTypeManager.GetAllCardTypes() in F:\Program Files\easyMule\Incoming\asp.net与extjs开发点卡在线销售系统\Y2毕业设计\项目源码\GameCardShop\GameCardShopBLL\Auto\CardTypeManager.cs:37

[TargetInvocationException: 调用的目标发生了异常。]
System.RuntimeMethodHandle._InvokeMethodFast(Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner) +0
System.RuntimeMethodHandle.InvokeMethodFast(Object target, Object[] arguments, Signature sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner) +72
System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks) +308
System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) +29
System.Web.UI.WebControls.ObjectDataSourceView.InvokeMethod(ObjectDataSourceMethod method, Boolean disposeInstance, Object& instance) +480
System.Web.UI.WebControls.ObjectDataSourceView.ExecuteSelect(DataSourceSelectArguments arguments) +1960
System.Web.UI.WebControls.BaseDataList.GetData() +57
System.Web.UI.WebControls.DataList.CreateControlHierarchy(Boolean useDataSource) +284
System.Web.UI.WebControls.BaseDataList.OnDataBinding(EventArgs e) +56
System.Web.UI.WebControls.BaseDataList.DataBind() +52
System.Web.UI.WebControls.BaseDataList.EnsureDataBound() +76
System.Web.UI.WebControls.BaseDataList.CreateChildControls() +63
System.Web.UI.Control.EnsureChildControls() +87
System.Web.UI.Control.PreRenderRecursiveInternal() +50
System.Web.UI.Control.PreRenderRecursiveInternal() +170
System.Web.UI.Control.PreRenderRecursiveInternal() +170
System.Web.UI.Control.PreRenderRecursiveInternal() +170
System.Web.UI.Control.PreRenderRecursiveInternal() +170
System.Web.UI.Control.PreRenderRecursiveInternal() +170
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2041


源代码是

        private static IList<CardType> GetCardTypesBySql( string safeSql )

        {

            List<CardType> list = new List<CardType>();



			try

			{

147行－－－－－－                  DataTable table = DBHelper.GetDataSet( safeSql );

				

				foreach (DataRow row in table.Rows)

				{

					CardType cardType = new CardType();

					

					cardType.CardTypeId = (int)row["CardTypeId"];

					cardType.CardTypeName = (string)row["CardTypeName"];

					cardType.CardPrice = (int)row["CardPrice"];

					cardType.CardImage = (string)row["CardImage"];

	

					list.Add(cardType);

				}

	

				return list;

			}

            catch (Exception e)

            {

                Console.WriteLine(e.Message);

166行－－－      throw e;              }



        }

我设置断点，发现只执行到147行，输出：
名称 值 类型
safesql "select * from CardType" String
table null System.Data.DataTable
list count＝0

大家分析分析，给个意见，谢谢