Virtual Scrolling and Persisting Selected Rows

[Dave]

I have a grid setup to use Virtual Scrolling as well as having a GridClientSelectColumn.  What I would like to do is be able to select X records from Page 1.  Then scroll to page 3 and select Y more records.  On a postback I want RadGrid1.SelectedItems.Count to be X + Y. Right now it is only showing Y records.  Is this possible?

[Radoslav]

Hi Dave,

To achieve the desired functionality you could try keeping all selected rows id's into the server side Dictionary collection:

public Dictionary<string, bool> SelectedItems
{
   get
   {
       if (Session["SelectedItems"] == null)
       {
            Session["SelectedItems"] = new Dictionary<string, bool>();
       }

       return Session["SelectedItems"] as Dictionary<string, bool>;
   }
   set
   {
       Session["SelectedItems"] = value;
   }
}

On RadGrid.SelectedIndexChanged event handler you could add the new selected items' ID or remove unselected rows:

void RadGrid1_SelectedIndexChanged(object sender, EventArgs e)
{
    SaveSelectedItems();
}
private void SaveSelectedItems()
{
   foreach (GridItem item in RadGrid1.Items)
   {
       if (item is GridDataItem)
       {
           GridDataItem dataItem = item as GridDataItem;
           if (item.Selected)
           {
               if (!SelectedItems.ContainsKey(dataItem["CustomerID"].Text))
               {
                   SelectedItems.Add(dataItem["CustomerID"].Text, true);

               }
            }
           else
           {
               if (SelectedItems.ContainsKey(dataItem["CustomerID"].Text))
               {
                  SelectedItems.Remove(dataItem["CustomerID"].Text);
               }
          }
       }
   }
 }

Additionally I am sending you a simple example which demonstrates the desired functionality. Please check it out and let me know if it helps you.

Greetings,
Radoslav
the Telerik team