これを試してください。
private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
{
ComboBox nameComboBox = e.Control as ComboBox;
if (dataGridView1.CurrentCell.ColumnIndex == 0)
{
if (nameComboBox != null)
{
((ComboBox)e.Control).DropDownStyle = ComboBoxStyle.DropDown;
((ComboBox)e.Control).AutoCompleteSource = AutoCompleteSource.ListItems;
((ComboBox)e.Control).AutoCompleteMode = System.Windows.Forms.AutoCompleteMode.Suggest;
nameComboBox .SelectedIndexChanged -= (nameComboBox _SelectedIndexChanged);
nameComboBox .SelectedIndexChanged += (nameComboBox _SelectedIndexChanged);
}
}
}
private void nameComboBox_SelectedIndexChanged(object sender, EventArgs e)
{
if (dataGridView1.CurrentCell.ColumnIndex == 1)
{
var rowindex = dataGridView1.CurrentCell.RowIndex;
if (dataGridView1[1, rowindex].EditedFormattedValue != null)
{
Consol.WriteLine(dataGridView1[1, rowindex].EditedFormattedValue.ToString());
}
else
{
//No value in cell
}
}
}