protected void Repeater_OnItemDataBound(object sender, RepeaterItemEventArgs e) { tblData tbldata= e.Item.DataItem as tblData;

 RequiredFieldValidator val = (RequiredFieldValidator)e.Item.FindControl("rfv");   if (tbldata.FieldName.ToUpper().Contains("NOT NULL"))  { TextBox tb = (TextBox)e.Item.FindControl("txtDATFieldName"); val.ControlToValidate = tb.ID; } else  { val.Enabled = false; // disable when you dont need a validator } } 

protected void Repeater_OnItemDataBound(object sender, RepeaterItemEventArgs e) { tblData tbldata = e.Item.DataItem as tblData; RequiredFieldValidator val = (RequiredFieldValidator)e.Item.FindControl("rfv"); if (tbldata.FieldName.ToUpper().Contains("NOT NULL")) { TextBox tb = (TextBox)e.Item.FindControl("txtDATFieldName"); val.ControlToValidate = tb.ID; } else { val.Enabled = false; // disable when you dont need a validator } }