To reproduce: public partial class Form1 : Form { public Form1() { InitializeComponent(); var data = new List<Thing>(); this.radGridView1.DataSource = data ; this.radGridView1.DataError += RadGridView1_DataError; } private void RadGridView1_DataError(object sender, Telerik.WinControls.UI.GridViewDataErrorEventArgs e) { } public class Thing { private Thing() { } } }