Q: Refresh Items of DataGridViewComboBoxColumn after DataSource Change I have a DataGridViewComboBoxColumn called myCmb:
        DataTable dtLevel = Level.SearchLevel(id);

        myCmb.DataSource = dtLevel;
        myCmb.ValueMember = "idLevel";
        myCmb.DisplayMember = "cLevel";

This is inside a method, at the first time it's ok but when the method is called for second time it seems there's a problem with Items property of myCmb because myCmb.Items.Count is 0 and there's an error When I show this cell in the grid.
How can I refresh Items of myCmb when datasource change?

A: You will need to set the datasource to null before setting the values. The code below should work fine. 
DataTable dtLevel = Level.SearchLevel(id);
myCmb.DataSource = null;
myCmb.DataSource = dtLevel;
myCmb.ValueMember = "idLevel";
myCmb.DisplayMember = "cLevel";

Hope this helps! 
