Displaying a Title and an Icon in a ToolTip window

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Introduction

There are a lot of articles about ToolTip controls. However, all of them do not support displaying a title and an icon. So I am sharing my ToolTip control named ScToolTip which supports displaying of a title and an icon.

Using the Control

To use the control, you just drag the control onto the form from the Visual Studio .NET toolbox. Then each control on the form will have three new properties that you can set for the particular object. Visual Studio will add the additional code automatically to support displaying tooltip for controls.

Points of Interest

The ScToolTip class is declared as follows:

[
ProvideProperty("ToolTip",typeof(Control)),
ProvideProperty("TipTitle",typeof(Control)),
ProvideProperty("IconType", typeof(Control)),
]
public class ScToolTip : Component,IExtenderProvider

To display different titles and icons, you must fill the TOOLINFO structure like this:

TOOLINFO toolinfo = new TOOLINFO();
toolinfo.hwnd = handle;
// the window handle which will accept
// the TTN_NEEDTEXT message sended
// by the native tooltip window.

toolinfo.uFlags = TTF_IDISHWND;
toolinfo.uId = control.Handle;
toolinfo.lpszText = LPSTR_TEXTCALLBACKW;
// the native tooltip window sends
// the TTN_NEEDTEXT message to the owner
// window to retrieve the text.

When the owner window accepts the TTN_NEEDTEXT message, we do this:

if (m.Msg == NativeMethods.WM_NOTIFY)
{
    NativeMethods.NMHDR hdr = 
      (NativeMethods.NMHDR)
      Marshal.PtrToStructure(m.LParam, 
      typeof(NativeMethods.NMHDR));

    if (hdr.code == NativeMethods.TTN_NEEDTEXT)
    {
        Control control = 
                Control.FromHandle(new IntPtr(hdr.idFrom));
        if (control != null)
        {
            string text = GetToolTip(control);
            //.Replace("\\n",Environment.NewLine);

            string title = GetTipTitle(control);
            int icon = (int)GetIconType(control);

            // change the title and icon 
            NativeMethods.SendMessage(new HandleRef(this, 
                this.Handle),NativeMethods.TTM_SETTITLE,icon,title);

            NativeMethods.NMTTDISPINFO info = 
              (NativeMethods.NMTTDISPINFO)
              Marshal.PtrToStructure(m.LParam, 
              typeof(NativeMethods.NMTTDISPINFO));
            info.lpszText = text;
            Marshal.StructureToPtr(info,m.LParam,true);
        }
    }
}

References

This article was inspired by wilsone8's article "Building a Ballontooltip provider in C#".