I am having trouble with paging in gridview control.
GridView was created in runtime:

        System.Web.UI.WebControls.GridView gvProgrm = new GridView();

           gvProgrm.AllowSorting = true; //(Sorting works perfectly)

        gvProgrm.AllowPaging = true;
            gvProgrm.PageIndex = 0;
            gvProgrm.PagerSettings.FirstPageText = "First";
            gvProgrm.PagerSettings.LastPageText = "Last";
            gvProgrm.PagerSettings.NextPageText = "Next";
            gvProgrm.PagerSettings.PreviousPageText = "Previous";
            gvProgrm.PagerSettings.Mode = PagerButtons.NextPreviousFirstLast;
            gvProgrm.PagerSettings.Position = PagerPosition.Bottom;
            gvProgrm.PagerSettings.Visible = true;
            gvProgrm.PageSize = 20;


            BuildColumnsDynamically(); // creates and adds columns dynamically
            gvProgrm.Visible = true;

            gvProgrm.DataSource = ds;
            gvProgrm.DataBind();

            private void InitializeComponent()
        {
            this.gvProgrm.Sorting += new GridViewSortEventHandler(this.gvProgrm_Sorting);
            this.gvProgrm.PageIndexChanging += new GridViewPageEventHandler(this.gvProgrm_PageIndexCh anging);
            this.Load += new System.EventHandler(this.Page_Load);

        }

        protected void gvProgrm_PageIndexChanging(object sender, GridViewPageEventArgs e)
         {
             //GridView1.DataSource = SortDataTable(GridView1.DataSource as DataTable, true);
             gvProgrm.DataSource = SortDataTable(dt, true);
             gvProgrm.PageIndex = e.NewPageIndex;
             gvProgrm.DataBind();
         }

When I set to AllowPaging = true, I get the error:

Object reference not set to an instance of an object.Object reference not set to an instance of an object.

Please advise.

Thanks.

the code looks good.. I don't know why you have an error there.. what happens if you invert the allowsorting and allowpaging.. the error is in the same place???

HTH

Gonzalo

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When gvProgrm.AllowPaging = false - it works fine.

It would be very useful to find out what part of the code throws the object reference exception. Otherwise, it's like searching for a needle in a haystack.

Try setting a break point of the line that creates the GridView and then step through it line by line to see where it breaks.

Imar


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Imar,
 already stepped through the code, it brakes on:

 gvProgrm.DataBind();

 with error:

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

 Source Error:


 Line 85:
 Line 86: gvProgrm.DataSource = ds;
 Line 87: gvProgrm.DataBind();
 Line 88:
 Line 89: Panel1.Controls.Add(gvProgrm);


Source File: c:\inetpub\wwwroot\ETM_Queue\Grid.aspx.cs Line: 87

If this doesn't break:

    gvProgrm.DataSource = ds;

then it stands to reason that gvProgrm isn't null.

Are you sure ds is not null? That's the only other thing that could be causing this error.

-Peter

Thanks for replying Peter,
dataset is OK - it has data,
also, the error happend when AllowPaging is set to true

Vadim, pay attention to your data source. I suppose you have a complex object for it that is not completely restored.

Try to debug some binding event handler to see all ds properties bound. I can suppose some of them will be null.

I know from having gone through the same steps with debugger that
1) The nullexception on databind() error can happen when Datasources are fine ie... not null... and
2) the gridvew is fine

In a very simple class I allocate a gridview [gridview grd = new gridView()] , then setting css class properties, data source etc. With paging off - NO problem. Paging on - null exception.

Sorry I dont have a solution yet. It probably has something to do with the paging even not being handled correctly... but its late and Im to tired to deal with it right now. Not to mention that I'm lazy.

Did you find that it had to do with how you handled paging event?