Create an Event for when this,toplevel value changes

Question

I want to be able to have my application to always be on top. so when I open a new program and that becomes on top even though I have this.TopLevel value set to true, the application will see it is not on top no more and then go back on top. I know I can do this with a timer, but I am hoping their is a better way.

But should you be determining what window appears to the user in their multitasking environment? — Charles May, Jul 13 '17 at 17:41
this is a overlay application that has a check box to activate this feature. — Jacob Lenertz, Jul 13 '17 at 17:42
Just in case you are using WPF, it has a built-in feature to keep the application on top. — Ian H., Jul 13 '17 at 18:25

score 3 · Accepted Answer · answered Jul 13 '17 at 18:31

You can use a method located in user32.dll.

using System.Runtime.InteropServices;

You are going to need these variables:

private static readonly IntPtr HWND_TOPMOST = new IntPtr(-1);
private const UInt32 SWP_NOSIZE = 0x0001;
private const UInt32 SWP_NOMOVE = 0x0002;
private const UInt32 TOPMOST_FLAGS = SWP_NOMOVE | SWP_NOSIZE;

Import the method from the DLL...

[DllImport("user32.dll")] 
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int X, int Y, int cx, int cy, uint uFlags);

Then in your code, use this to set the window position to the topmost window.

SetWindowPos(this.Handle, HWND_TOPMOST, 0, 0, 0, 0, TOPMOST_FLAGS);

I hope this helps you!

score 1 · Answer 2 · answered Jul 13 '17 at 18:15

1

I suggest you catch the event for new windows and see if you are on top after the new window opens:

https://stackoverflow.com/a/40698254/2557128

answered Jul 13 '17 at 18:15

NetMage

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Create an Event for when this,toplevel value changes

2 Answers2