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I get an error:  Object reference not set to an instance of an object

Posted on 2004-04-02
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Medium Priority
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Last Modified: 2008-02-01
Hi, I'm getting the error:  
"Object reference not set to an instance of an object"

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:
Line 589:                        StatusBox.Text = "view is not null";
Line 590:                  
Line 591(this line):                  batchList.DataSource = view;
Line 592://                  batchList.DataBind();
Line 593:            }

Stack Trace:

[NullReferenceException: Object reference not set to an instance of an object.]
   LoadRunner.WebForm1.displayMenu() in c:\inetpub\wwwroot\loadrunner\webform1.aspx.cs:591
   LoadRunner.WebForm1.Page_Load(Object sender, EventArgs e) in c:\inetpub\wwwroot\loadrunner\webform1.aspx.cs:319
   System.Web.UI.Control.OnLoad(EventArgs e)
   System.Web.UI.Control.LoadRecursive()
   System.Web.UI.Page.ProcessRequestMain()


The code is as following, where batchList is declared
protected System.Web.UI.WebControls.DataGrid batchList;

==
            private void displayMenu()
            {
                  //read the Xml into DataSet.
                  DataSet ds = new DataSet();
                  ds.ReadXml(Server.MapPath("application.xml"));

                  //Choose the "batchfile"
                  DataView view = ds.Tables["batchfile"].DefaultView;
                  view.Sort = "order" + " DESC";
                  
                  if(view==null)
                        StatusBox.Text = "view is null";
                  else
                        StatusBox.Text = "view is not null";
                  
                  batchList.DataSource = view;
                  batchList.DataBind();
==
This code was working perfectly before, and now it doesn't.  application.xml exists in the appropriate directory (c:\inetput\wwwroot\loadrunner\) and is valid.  I just can't seem to figure out why "batchList.DataSource = view" can be generating an error.

Thank you very much.
0
Comment
Question by:tnakamur
7 Comments
 
LVL 22

Expert Comment

by:_TAD_
ID: 10744732


new need to set you variable to an instance of the object.

That is, get a currently running instance, or create a new one


protected System.Web.UI.WebControls.DataGrid batchList = new DataGrid();

or

protected System.Web.UI.WebControls.DataGrid batchList = DataGrid1; // assuming that you have a datagrid1 on your form
0
 
LVL 22

Expert Comment

by:_TAD_
ID: 10744747


>>new need to set you variable to an instance of the object.    (??)

YOU need to set YOUR .....  holy fat fingers batman!  

0
 

Author Comment

by:tnakamur
ID: 10744881
Ahh.  That's gone, but I get the exact same error in the different part of the code:

foreach(DataGridItem item in batchList.Items)
{
                //this line now
      ((CheckBox)item.FindControl("check1")).Enabled = false;
}

Any ideas on this one?
      
0
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LVL 3

Expert Comment

by:gillit
ID: 10744888
Make sure you included in your aspx page:
<asp:DataGrid id="batchList" runat="server">
    ....
</asp:DataGrid>
0
 
LVL 3

Expert Comment

by:gillit
ID: 10744910
oops... posted right after you replied

As for your last post... make sure check1 included in your aspx page and/or declared.
0
 
LVL 22

Expert Comment

by:_TAD_
ID: 10746114


Hmmm... this should work.


I'll have to run some tests to see if I can reproduce the error
0
 
LVL 20

Accepted Solution

by:
TheAvenger earned 450 total points
ID: 10746636
I think your problems are all with the controls. In the first problem, the null value was probably batchList and not the view. Now you have another problem with a control. Review your HTML code to see if all controls are declared correctly and they are configured to run on the server
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