行 56:                 {
行 57:                     string classid = Request.QueryString["ID"];
行 58:                     this.Label1.Text = ClassesService.GetClassesByClassesId(int.Parse(classid)).Pname;
行 59:                     this.Label2.Text = ClassesService.GetClassesByClassesId(int.Parse(classid)).Pname;
行 60:                     List<Prodects> plist = new List<Prodects>();

[InvalidOperationException: ExecuteReader 要求已打开且可用的连接。连接的当前状态为正在连接。]
   System.Data.SqlClient.SqlConnection.GetOpenConnection(String method) +4941580
   System.Data.SqlClient.SqlConnection.ValidateConnectionForExecute(String method, SqlCommand command) +11
   System.Data.SqlClient.SqlCommand.ValidateCommand(String method, Boolean async) +144
   System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result) +87
   System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method) +32
   System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior, String method) +141
   System.Data.SqlClient.SqlCommand.ExecuteDbDataReader(CommandBehavior behavior) +12
   System.Data.Common.DbCommand.System.Data.IDbCommand.ExecuteReader(CommandBehavior behavior) +10
   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(DataSet dataSet, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior) +287
   System.Data.Common.DbDataAdapter.Fill(DataSet dataSet) +94
   DAL.DBHelper.GetDataSet(String safeSql) in E:\网站\55世纪\DAL\DBHelper.cs:99
   DAL.ClassesService.GetClassesByClassesId(Int32 classesId) in E:\网站\55世纪\DAL\ClassesService.cs:196
   yrcp.Page_Load(Object sender, EventArgs e) in d:\网站\55世纪工贸2023\yrcp.aspx.cs:58
   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