getting the column number or column header in gridview

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C#

WF

How to get the selected column number or column header in datagridview, when doubleclick is made?
and i want to place date time picker in that column.
the code which I have used is this one:

void DataGridView1DoubleClick(object sender, EventArgs e)
{
MouseEventArgs args = (MouseEventArgs)e;
Point p = dataGridView1.PointToClient(new Point(args.X,args.Y));
DataGridView.HitTestInfo info = dataGridView1.HitTest(p.X, p.Y);
int Row = info.RowIndex;
int Col=info.ColumnIndex;
 
if(dataGridView1.Columns[info.ColumnIndex].Name == "Employee name")
     {

textBox1.Text="hello";            	textBox1.SetBounds(args.X,args.Y,dataGridView1.CurrentCell.Size.Width,dataGridView1.CurrentCell.Size.Height);
            	textBox1.Show();
            }
}

but the row index and column index is returned as -1
I have used checkbox column at column[0] is this because of that??
thanks in advance