Show form as a ToolTip

Question

I need to display a Form as a ToolTip of an UserControl. When the mouse is over the UserControl, the Form have to be show, and when the mouse leave that UserControl, the Form have to be hide.

I've overrided these events, in my UserControl class :

public partial class TreatedMetricsDisplay : UserControl
{
    private TreatedMetricsWindow _treatedMetricsWindow;
    public TreatedMetricsDisplay()
    {
        InitializeComponent();
        _treatedMetricsWindow = new TreatedMetricsWindow ();
    }

    protected override void OnMouseHover(EventArgs e)
    {
        base.OnMouseHover (e);
        this._treatedMetricsWindow.Show();
    }
    protected override void OnMouseLeave(EventArgs e)
    {
        base.OnMouseLeave (e);
        this._treatedMetricsWindow.Close ();
    }
}

No exceptions, but events are not called.

Answer 1

Here is a code sample that might help:

private void ToolTipControl_Load(object sender, EventArgs e)
    {
        AttachHandlers(this);
    }

    private void AttachHandlers(Control currentControl)
    {
        foreach (Control control in currentControl.Controls)
        {
            control.MouseHover += GenericMouseHover;
            control.MouseLeave += GenericMouseLeave;

            if (control.Controls.Count != 0)
            {
                AttachHandlers(control);
            }
        }
    }

    void GenericMouseLeave(object sender, EventArgs e)
    {
        // no need to hide it if there was no form created in first place
        if(_form != null && _form.Visible)
        Form.Hide();
    }

    private void GenericMouseHover(object sender, EventArgs e)
    {
        Form.Location = this.PointToClient(Cursor.Position);
        Form.Show();
    }

    ToolTipForm _form;
    private ToolTipForm Form
    {
        get
        {
            if (_form == null)
            {
                _form = new ToolTipForm();
            }
            return _form;
        }
    }

Answer 2

Showing the Form will steal the Focus, It will get activated. So, it isn't a good idea to show Form as ToolTip. It will not behave as one would expect.

You need to use ToolStripDropDown combined with ToolStripControlHost. Which makes it possible to show any control as tooltip(not exactly).

public partial class MainForm : Form
{
    private ToolStripDropDown dropDown = new ToolStripDropDown();
    public MainForm()
    {
        InitializeComponent();

        dropDown.Items.Add(new ToolStripControlHost(new ToolTipUserControl() { Size = new Size(200, 200) }));
    }

    protected override void OnMouseEnter(EventArgs e)
    {
        base.OnMouseEnter(e);
        dropDown.Show(MousePosition);
    }

    protected override void OnMouseLeave(EventArgs e)
    {
        base.OnMouseLeave(e);
        dropDown.Hide();
    }
}

ToolTipUserControl could be any Control which you want to show as tooltip.