Question

I have a ComboBox in a DataGridView. However I get an error when I run it:

Unable to cast object of type ‘System.Windows.Forms.DataGridView’ to type ‘System.Windows.Forms.ComboBox’.

What can I do to resolve this error?

 ComboBox comboBox;
    private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
    {
        if (e.Control is ComboBox)
        {
            comboBox = e.Control as ComboBox;

            if (dataGridView1.CurrentCell.ColumnIndex >= 0)
            {
                System.Diagnostics.Debug.WriteLine("Edit Control Showing");
                comboBox.SelectedIndexChanged -= new EventHandler(comboBoxItems_SelectedIndexChanged);
                comboBox.SelectedIndexChanged += new EventHandler(comboBoxItems_SelectedIndexChanged);

            }
        }
    }

    void comboBoxItems_SelectedIndexChanged(object sender, EventArgs e)
    {
        try
        {

            int comboBoxSelectedIndex = ((ComboBox)sender).SelectedIndex;
            string comboboxSelectedValue = ((ComboBox)sender).SelectedText;
            int gridViewSelectedRow = dataGridView1.CurrentRow.Index;
            if (comboBoxSelectedIndex >= 0 && gridViewSelectedRow >= 0)
            {
                System.Diagnostics.Debug.WriteLine("ComboBox Index - " + comboBoxSelectedIndex);
                System.Diagnostics.Debug.WriteLine("GridView Index - " + gridViewSelectedRow);
                if (comboBox != null)
                {
                    comboBox.SelectedIndexChanged -= new EventHandler(comboBoxItems_SelectedIndexChanged);



                }
            }
        }
        catch(Exception E)
        {

        }
    }

Answer 1

I would also recommend checking the sender object before attempting to cast it (would confirm what decyclone mentioned in his answer in addition to preventing casting errors):

if(sender is ComboxBox) {
      //cast
}