c# - Displaying tooltip over a disabled control

Question

I'm trying to display a tooltip when mouse hovers over a disabled control. Since a disabled control does not handle any events, I have to do that in the parent form. I chose to do this by handling the MouseMove event in the parent form. Here's the code that does the job:

    void Form1_MouseMove(object sender, MouseEventArgs e)
    {
        m_toolTips.SetToolTip(this, "testing tooltip on " + DateTime.Now.ToString());
        string tipText = this.m_toolTips.GetToolTip(this);
        if ((tipText != null) && (tipText.Length > 0))
        {
            Point clientLoc = this.PointToClient(Cursor.Position);
            Control child = this.GetChildAtPoint(clientLoc);
            if (child != null && child.Enabled == false)
            {
                m_toolTips.ToolTipTitle = "MouseHover On Disabled Control";
                m_toolTips.Show(tipText, this, 10000);
            }
            else
            {
                m_toolTips.ToolTipTitle = "MouseHover Triggerd";
                m_toolTips.Show(tipText, this, 3000);
            }
        }
    }

The code does handles the tooltip display for the disabled control. The problem is that when mouse hovers over a disabled control, the tooltip keeps closing and redisplay again. From the display time I added in the tooltip, when mouse is above the parent form, the MouseMove event gets called roughly every 3 seconds, so the tooltip gets updated every 3 seconds. But when mouse is over a disabled control, the tooltip refreshes every 1 second. Also, when tooltip refreshes above form, only the text gets updated with a brief flash. But when tooltip refreshes above a disabled control, the tooltip windows closes as if mouse is moving into a enabled control and the tooltip is supposed to be closed. but then the tooltip reappears right away.

Can someone tell me why is this? Thanks.

Answer 1

you can show the tooltip only once when mouse hits the disbled control and then hide it when mouse leaves it. Pls, take a look at the code below, it should be showing a tooltip message for all the disabled controls on the form

private ToolTip     _toolTip = new ToolTip();
private Control     _currentToolTipControl = null; 

public Form1()
{
    InitializeComponent();

    _toolTip.SetToolTip(this.button1, "My button1");
    _toolTip.SetToolTip(this.button2, "My button2");
    _toolTip.SetToolTip(this.textBox1, "My text box");
}

private void Form1_MouseMove(object sender, MouseEventArgs e)
{
    Control control = GetChildAtPoint(e.Location);
    if (control != null)
    {
        if (!control.Enabled && _currentToolTipControl == null)
        {
            string toolTipString = _toolTip.GetToolTip(control);
            // trigger the tooltip with no delay and some basic positioning just to give you an idea
            _toolTip.Show(toolTipString, control, control.Width/2, control.Height/2);
            _currentToolTipControl = control;
        }
    }
    else
    {
        if (_currentToolTipControl != null) _toolTip.Hide(_currentToolTipControl);
        _currentToolTipControl = null;
    }
}

hope this helps, regards