Datagridview: How to set a cell in editing mode?

Setting the CurrentCell and then calling BeginEdit(true) works well for me.

The following code shows an eventHandler for the KeyDown event that sets a cell to be editable.

My example only implements one of the required key press overrides but in theory the others should work the same. (and I'm always setting the [0][0] cell to be editable but any other cell should work)

    private void dataGridView1_KeyDown(object sender, KeyEventArgs e)
    {
        if (e.KeyCode == Keys.Tab && dataGridView1.CurrentCell.ColumnIndex == 1)
        {
            e.Handled = true;
            DataGridViewCell cell = dataGridView1.Rows[0].Cells[0];
            dataGridView1.CurrentCell = cell;
            dataGridView1.BeginEdit(true);               
        }
    }

If you haven't found it previously, the DataGridView FAQ is a great resource, written by the program manager for the DataGridView control, which covers most of what you could want to do with the control.

private void DgvRoomInformation_CellEnter(object sender, DataGridViewCellEventArgs e)
{
  if (DgvRoomInformation.CurrentCell.ColumnIndex == 4)  //example-'Column index=4'
  {
    DgvRoomInformation.BeginEdit(true);   
  }
}

Well, I would check if any of your columns are set as ReadOnly. I have never had to use BeginEdit, but maybe there is some legitimate use. Once you have done dataGridView1.Columns[".."].ReadOnly = False;, the fields that are not ReadOnly should be editable. You can use the DataGridView CellEnter event to determine what cell was entered and then turn on editing on those cells after you have passed editing from the first two columns to the next set of columns and turn off editing on the last two columns.