How to activate combobox on first click (Datagridview)

Question

In winforms, you need to click the combobox twice to properly activate it - the first time to focus it, the second time to actually get the dropdown list.

How do I c

Answer 1

Set the following on your DataGridView:

EditMode = EditOnEnter

This is probably the easiest solution and has been the workaround for many users here on SO when this question gets asked.

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EDIT :

Per here do the following:

Set the Editmode:

EditMode = EditOnKeystrokeOrF2

Modify the EditingControlShowing event on the datagridview:

private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
{
    ComboBox ctl = e.Control as ComboBox;
    ctl.Enter -= new EventHandler(ctl_Enter);
    ctl.Enter += new EventHandler(ctl_Enter);

}

void ctl_Enter(object sender, EventArgs e)
{
    (sender as ComboBox).DroppedDown = true;
}

This will get you your desired results. Let me know if that doesn't do it.

Answer 2

I realize this is an old question, but I figured I would give my solution to anyone out there that may need to be able to do this.

While I couldn't find any answers to do exactly this... I did find an answer to a different question that helped me.

This is my solution:

private void datagridview_CellEnter(object sender, DataGridViewCellEventArgs e)
    {
        bool validClick = (e.RowIndex != -1 && e.ColumnIndex != -1); //Make sure the clicked row/column is valid.
        var datagridview = sender as DataGridView;

        // Check to make sure the cell clicked is the cell containing the combobox 
        if(datagridview.Columns[e.ColumnIndex] is DataGridViewComboBoxColumn && validClick)
        {
            datagridview.BeginEdit(true);
            ((ComboBox)datagridview.EditingControl).DroppedDown = true;
        }
    }


private void datagridview_CurrentCellDirtyStateChanged(object sender, EventArgs e)
    {
        datagridview.CommitEdit(DataGridViewDataErrorContexts.Commit);
    }

The above code must be tied into the CellEnter event of the datagridview.

I hope this helps!

edit: Added a column index check to prevent crashing when the entire row is selected.

Thanks, Up All Night for the above edit

edit2: Code is now to be tied to the CellEnter rather than the CellClick event.

Thanks, HaraldDutch for the above edit

edit3: Any changes will committed immediately, this will save you from clicking in another cell in order to update the current combobox cell.

Answer 3

Set the DropDownStyle property of your combo box to DropDownList...

Answer 4

If you set the entire grid to EditOnEnter, you can get some pretty funky activity when you are on a text column. Here's my solution, which should be self explanatory. If you did not know the column names, you could just check the cell type on mousemove.

Private Sub GridView_CellMouseMove(sender As Object, e As System.Windows.Forms.DataGridViewCellMouseEventArgs) Handles GridView.CellMouseMove
    Select Case GridView.Columns(e.ColumnIndex).Name
        Case "Ad_Edit", "Size_Caption", "Demo_Code"
            GridView.EditMode = DataGridViewEditMode.EditOnEnter
        Case Else
            GridView.EditMode = DataGridViewEditMode.EditOnKeystrokeOrF2
    End Select
End Sub

Answer 5

I changed only the EditMode property of the datagridview to EditOnEnter and it's working perfectly.

EditMode  = EditOnEnter

Answer 6

Perhaps old.. But make sure to set ReadOnly property to false, else the cell wont enter editmode and therefore the EditingControl returns null and casting DroppedDown = true will cast a NullReferencException.