[NullReferenceException: 未将对象引用设置到对象的实例。]
   System.Data.OleDb.OleDbConnection.ValidateTransaction(OleDbTransaction transaction, String method) +18
   System.Data.OleDb.OleDbCommand.ValidateConnectionAndTransaction(String method) +40
   System.Data.OleDb.OleDbCommand.ExecuteReaderInternal(CommandBehavior behavior, String method) +56
   System.Data.OleDb.OleDbCommand.ExecuteReader(CommandBehavior behavior) +116
   System.Data.OleDb.OleDbCommand.System.Data.IDbCommand.ExecuteReader(CommandBehavior behavior) +4
   System.Data.Common.DbDataAdapter.FillInternal(DataSet dataset, DataTable[] datatables, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior) +130
   System.Data.Common.DbDataAdapter.Fill(DataTable[] dataTables, Int32 startRecord, Int32 maxRecords, IDbCommand command, CommandBehavior behavior) +162
   System.Data.Common.DbDataAdapter.Fill(DataTable dataTable) +115
   DBsql.GetDataTable(String safeSql) in e:\site\glxy\App_Code\DBsql.cs:76
   CtorDatabind.Repeaterbind(Repeater repert1, String sqlstr) in e:\site\glxy\App_Code\CtorDatabind.cs:103
   xuesheng.Page_Load(Object sender, EventArgs e) in e:\site\glxy\xuesheng.aspx.cs:20
   System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +14
   System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +35
   System.Web.UI.Control.OnLoad(EventArgs e) +99
   System.Web.UI.Control.LoadRecursive() +50
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +627