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Ticket Q238860
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Detect scroll to top/bottom

created 15 years ago

Hi,
I was wondering what's the best way to implement the following:
I add x amount of items to a collection that's bound to a XtraGrid and center the displayed row to the row/cell with the mean value of the collection via gridview.MakeRowVisible().
I'd like to add additional items to the collection whenever the client reaches the top or bottom when scrolling, so it appears like it's a virtual grid (scrolling is only allowed via mouse wheel in my grid), when in reality additional items are added to the collection "on-demand" only.
Thanks,
Tom

Comments (3)
DevExpress Support Team 15 years ago

    Hi Tom,
    To achieve your goal handle the TopRowChanged event on the following manner:

    C#
         private void gridView1_TopRowChanged(object sender, EventArgs e)  
     {  
         Text = string.Empty;  
         int rowCount = gridView1.DataRowCount;  
         this.BeginInvoke(new MethodInvoker(delegate { FireMyEvent(rowCount); }));  
     }  

     void FireMyEvent(int rowCount)  
     {  
         if (gridView1.IsRowVisible(0) == RowVisibleState.Visible) MyMethod(false);  
         if (gridView1.IsRowVisible(rowCount - 1) == RowVisibleState.Visible) MyMethod(true);  
     }  


     void MyMethod(bool bottom)  
     {  
///  
     }

    Attached is a sample project, illustrating this approach. Please review it, and inform me whether it meets your requirements.
    Thanks
    Dimitros

    TF TF
    Thomas Frey 15 years ago

      Perfect, this works great! Thanks

      TF TF
      Thomas Frey 15 years ago

        solved

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