Show Tooltip programatically on a control inheriting from UserControl

Question

I have a custom control inheriting from the UserControl class. It has got a ToolTip property but I need to show it when the mouse is dragged over it.

The Tooltip.Show method expects the second argument of type Control. I'm not sure how to with it.

Any ideas/help appreciated.

Answer 1

SetToolTip() only needs to be called once

class Foo : Form {
     ToolTip tooltip = new ToolTip();

     public Foo(){
          tooltip.SetToolTip(this, "This is a tooltip!"); 
          foreach(Control ctrl in this.Controls) {
                tooltip.SetToolTip(ctrl, "This is a tooltip!");
            }
     }
}

Answer 2

Instantiate your tooltip in constructor and show it on mouse hover event.

Taken from Joseph's answer in stackoverflow

public ToolTip tT { get; set; }

public ClassConstructor()
{
tT = new ToolTip();
}

private void MyControl_MouseHover(object sender, EventArgs e)
{
tT.Show("Why So Many Times?", this);
}

Hope it helps.

Answer 3

I needed this myself, and found the partial solution offered above could be improved upon.

Basically, you need to set the MouseHover event for all applicable child controls to the MouseHover of the parent UserControl.

this can be done with code as below in the MyUserControl class constructor:

class MyUserControl:UserControl
{
   string strTooltip;
   public ToolTip toolTip
   {
    get;
    set;
   }

   public MyUserControl()
   {
     toolTip = new ToolTip();
     foreach(Control ctrl in this.Controls)
     {
      ctrl.MouseHover += new EventHandler(MyUserControl_MouseHover);
      ctrl.MouseLeave += new EventHandler(MyUserControl_MouseLeave);
     }
  }
  void MyUserControl_MouseLeave(object sender, EventArgs e)
  {
    toolTip.Hide(this);
  }

  void MyUserControl_MouseHover(object sender, EventArgs e)
  {
    toolTip.Show(strToolTip, this, PointToClient(MousePosition));
  }
}

Note that we are using the PointToClient(MousePosition) to position the tooltip where the usercontrol is located.

Otherwise, sometimes, it can cause the tooltip to get displayed at a random location on the screen. Hope this helps someone! :)

Answer 4

Just hit this problem myself today, and came up with this rather simple solution.

Add the following source file to your codebase somewhere (I put it in a file ToolTipEx.cs)

namespace System.Windows.Forms
{
    public static class ToolTipEx
    {
        private static void SetTipRecurse(ToolTip toolTip, Control control, string tip)
        {
            toolTip.SetToolTip(control, tip);

            foreach (Control child in control.Controls)
                SetTipRecurse(toolTip, child, tip);
        }

        public static void SetTooltip(this ToolTip toolTip, UserControl control, string tip)
        {
            SetTipRecurse(toolTip, control, tip);
        }
    }
}

If it is in another DLL, make sure the DLL is referenced.

Then all you have to do is make the normal call to toolTip.SetToolTip(myControl, "some tip"); and the compiler will take care of the rest for you.

Because the function essentially extends the ToolTip.SetToolTip() method to one having the signature

ToolTip(UserControl control, string tip);

which is higher up in the hierachy than the original

ToolTip(Control control, string tip);

When we are dealing with a UserControl, it will be called instead of the original.

The new method does a simple recursive call to give all sub controls then same tool tip as the parent control.

This code assumes that the UserControl will not have other controls added to it after the call to SetToolTip is made.