Question

I am creating a windows forms application, and I need a combobox containing items, that each opens another combobox and the user can specialize the selection.

An example:
I have 2 items in my combobox.
Danish words
English words

When the user selects English Words, then it opens another combobox, where the user can select an english word.

How do I create this kind of combobox?

**EDIT: It does not have to combobox, just something that achieves the same result

An image of the problem:

Answer 1

Try this code:
I’ve created two ComboBoxes one named language_CmbBx and one named words_CmbBx.
I set words_CmbBx.Visible = false;

 private void language_CmbBx_SelectedIndexChanged(object sender, EventArgs e)
        {
            this.Cursor = new Cursor(Cursor.Current.Handle);
            words_CmbBx.Location = new Point(language_CmbBx.Location.X + language_CmbBx.Width, GetLocalMousePos().Y);
            words_CmbBx.Visible = true;

        }

This method is to get your mouseposition or the position of the selectedItem you wanted:

    public Point GetLocalMousePos()
    {
        Point screenPos = Cursor.Position;
        return this.PointToClient(screenPos);
    }

The only problem is that the ComboBox won’t stay open and I didn’t find a way yet to let it stay open.

As I already mentioned it is really difficult to achieve what you want using ComboBoxes, try to use ListBox instead:

    private void languages_LstBx_SelectedIndexChanged(object sender, EventArgs e)
    {
        this.Cursor = new Cursor(Cursor.Current.Handle);
        words_LstBx.Location = new Point(language_LstBx.Location.X + language_LstBx.Width, GetLocalMousePos().Y);
        words_LstBx.Visible = true;
    }

Same code, better result!

You can download my VS2010-project here: http://www.abouchleih.de/projects/twocomboboxes.zip