Hi Nandakumar,
You can't set all the cells editable at a time on button click.
To set all the cells in EditMode set the DataGridView BeginEdit property on cellclick event.
When you click on any cell automatically the cell become editable.
C#
private void dataGridView1_CellClick(object sender, DataGridViewCellEventArgs e)
{
dataGridView1.BeginEdit(true);
}
VB.Net
Private Sub dataGridView1_CellClick(ByVal sender As Object, ByVal e As DataGridViewCellEventArgs)
dataGridView1.BeginEdit(True)
End Sub