How to explicitly set taskbar icon?

Answer 1

The icon shown on the task bar is taken from the window itself. If the only window is the standard Windows MesssageBox, then you'll get some sort of OS default. You have to create your own window and give it an icon, then Windows will use that.

Answer 2

This looks like just sample code. If the real code is a non-console Windows application, you can do this:

Give your application's main window a task bar icon by calling SetIcon(). Then when you call MessageBox(), set the first parameter to the HWND of your application's main window.

Answer 3

WNDCLASSEX wndclass;

wndclass.cbSize        = sizeof(wndclass);
// ..
wndclass.hIconSm       = ExtractIconEx( ... );
RegisterClassEx(&wndclass);

HWDN wnd = CreateWindow(...)

Answer 4

Why not just add an icon resource to the EXE? I'm pretty sure Windows will try that before falling back to the "generic" icons.

Answer 5

Create a form but never show it then assign it an icon and use that as the parent of your message box.

This hides the icon:

using (var f = new Form())
{
    MessageBox.Show(f,"my message");
}

This will create an icon:

using (var f = new Form())
{
    f.Icon = Resources.IconUpload;
    f.Location=new Point(-1000,-1000);
    f.StartPosition = FormStartPosition.Manual;
    f.Show();
    MessageBox.Show(f,"my message");
}