adding text to the value of a gridview cell winforms

I have a gridview -  I am trying to add text to a cells value when the gridview is loading by using the formatting event. Bu unfortunately the app does not like what I have done at all :D Does anyone know how to append text to the end of the value in a gridview cell

 private void gvDataWords_CellFormatting(object sender, CellFormattingEventArgs e)
        {
            Char degree = (Char)176;
            if (e.CellElement.RowInfo.Cells["thevalue"].Value != null)
            {
                string title = e.CellElement.RowInfo.Cells["thelabel"].Value.ToString();
                //if(title == "Temperature" && tempMultiplier == "1")
                //{
                int myVal = Int32.Parse(e.CellElement.RowInfo.Cells["thevalue"].Value.ToString());
                e.CellElement.RowInfo.Cells["thevalue"].Value = Convert.ToString(myVal) + degree + " C";
                //}
                //if ((string)e.CellElement.RowInfo.Cells["thelabel"].Value == "Temperature" && tempMultiplier == "1")
                //{
                   // e.CellElement.RowInfo.Cells["thevalue"].Value = Convert.ToString(thevalue.Value + "°");
                //}
            }
            {

            }
        }

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