C# Force Form Focus

Question

So, I did search google and SO prior to asking this question. Basically I have a DLL that has a form compiled into it. The form will be used to display information to the sc

Answer 1

I also had trouble activating and bringing a window to the foreground. Here is the code that eventually worked for me. I'm not sure if it will solve your problem.

Basically, call ShowWindow() then SetForegroundWindow().

using System.Diagnostics;
using System.Runtime.InteropServices;

// Sets the window to be foreground
[DllImport("User32")]
private static extern int SetForegroundWindow(IntPtr hwnd);

// Activate or minimize a window
[DllImportAttribute("User32.DLL")]
private static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);
private const int SW_SHOW = 5;
private const int SW_MINIMIZE = 6;
private const int SW_RESTORE = 9;

private void ActivateApplication(string briefAppName)
{
    Process[] procList = Process.GetProcessesByName(briefAppName);

    if (procList.Length > 0)
    {
        ShowWindow(procList[0].MainWindowHandle, SW_RESTORE);
        SetForegroundWindow(procList[0].MainWindowHandle);
    }
}

Answer 2

Huge thanks people.
I think I've made it a bit shorter, here's what I put on a seperate thread and seems to be working ok.

private static void StatusChecking()
{
    IntPtr iActiveForm = IntPtr.Zero, iCurrentACtiveApp = IntPtr.Zero;
    Int32 iMyProcID = Process.GetCurrentProcess().Id, iCurrentProcID = 0;
    IntPtr iTmp = (IntPtr)1;

    while (bIsRunning)
    {
        try
        {
            Thread.Sleep(45);
            if (Form.ActiveForm != null)
            {
                iActiveForm = Form.ActiveForm.Handle;
            }
            iTmp = GetForegroundWindow();
            if (iTmp == IntPtr.Zero) continue;
            GetWindowThreadProcessId(iTmp, ref iCurrentProcID);
            if (iCurrentProcID == 0)
            {
                iCurrentProcID = 1;
                continue;
            }
            if (iCurrentProcID != iMyProcID)
            {
                SystemParametersInfo(SPI_GETFOREGROUNDLOCKTIMEOUT, 0, IntPtr.Zero, 0);
                SystemParametersInfo(SPI_SETFOREGROUNDLOCKTIMEOUT, 0, IntPtr.Zero, SPIF_SENDCHANGE);
                BringWindowToTop(iActiveForm);
                SetForegroundWindow(iActiveForm);
            }
            else iActiveForm = iTmp;
        }
        catch (Exception ex)
        {
            Definitions.UnhandledExceptionHandler(ex, 103106);
        }
    }
}

I don`t bother repasting the definitions...