Server Error in '/' Application.

Index was outside the bounds of the array.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.IndexOutOfRangeException: Index was outside the bounds of the array.

Source Error:

Line 179:        }
Line 180:        DataRow[] thispart = partall.Select("CategoryId=" + tq);
Line 181:        int thislft = Convert.ToInt32(thispart[0]["Lft"].ToString());
Line 182:        int thisrgt = Convert.ToInt32(thispart[0]["Rgt"].ToString());
Line 183:        DataRow[] fathercate = partall.Select("Lft<=" + thislft + " and Rgt>=" + thisrgt);

Source File: d:\vhostroot\localuser\cnkb8\www\sub.master.cs    Line: 181

Stack Trace:

[IndexOutOfRangeException: Index was outside the bounds of the array.]
   cn_sub.showinfo(String tq) in d:\vhostroot\localuser\cnkb8\www\sub.master.cs:181
   cn_sub.Page_Load(Object sender, EventArgs e) in d:\vhostroot\localuser\cnkb8\www\sub.master.cs:90
   System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +52
   System.Web.UI.Control.OnLoad(EventArgs e) +97
   System.Web.UI.Control.LoadRecursive() +61
   System.Web.UI.Control.LoadRecursive() +134
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +693

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.8.4110.0