Gridview is Very slow on the Cells change event

[vuyiswamb]

Good Day all

i have a Ultrawebgrid i n my page and i display Data in this Way

STAFF                CYCLES
=========================
Galloway A Ms	  20,22,23,24,25,26
Gama, E	          20,22,24,25
Grieve S Ms	  20,25,26
Jones D Dr	  24,26

and a user can select the Staff in the Grid by Holding a Control key and i have trapped the selection in the Gridstaff_SelectedCellsChange and handled it like this

protected void Gridstaff_SelectedCellsChange(object sender, SelectedCellsEventArgs e)
    {
        Change_Control_Availability_Cycles_Enable(); //Enable the Disabled button

        List<String> Array_To_Be_Replaced = new List<String>(); //This are the Values to be replaced, they will be stored in this array

        foreach (UltraGridCell cell in Gridstaff.DisplayLayout.SelectedCells)
        {
            if (cell.Column.Index == 0)
            {

                if (cell.Value != null && cell.Value.ToString() != "")
                {
                    cell.Style.ForeColor = System.Drawing.Color.Red;

                    Array_To_Be_Replaced.Add(cell.Value.ToString());

                }

            }

            else
            {

            }
        }
        Session["Array_To_Be_Replaced"] = Array_To_Be_Replaced;

    }

Now when my user is selecting the Staff, this page becomes very Slow.

Can you please advice me on the approach and the Bottleneck in my code.

Thank you