Enable only one instance of WPF application - wpf

Question

I have WPF allocation and I want to be able to open only one instance of my application.
So i have this 2 classes:
public sealed class SingleInstance
{
public static bool AlreadyRunning()
{
bool running = false;
try
{
// Getting collection of process
Process currentProcess = Process.GetCurrentProcess();
// Check with other process already running
foreach (var p in Process.GetProcesses())
{
if (p.Id != currentProcess.Id) // Check running process
{
if (p.ProcessName.Equals(currentProcess.ProcessName) == true)
{
running = true;
IntPtr hFound = p.MainWindowHandle;
if (User32API.IsIconic(hFound)) // If application is in ICONIC mode then
User32API.ShowWindow(hFound, User32API.SW_RESTORE);
User32API.SetForegroundWindow(hFound); // Activate the window, if process is already running
break;
}
}
}
}
catch { }
return running;
}
}
And:
public class User32API
{
[DllImport("User32.dll")]
public static extern bool IsIconic(IntPtr hWnd);
[DllImport("User32.dll")]
public static extern bool SetForegroundWindow(IntPtr hWnd);
[DllImport("User32.dll")]
public static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);
public const int SW_RESTORE = 9;
}
App.xaml:
protected override void OnStartup(StartupEventArgs e)
{
if (SingleInstance.AlreadyRunning())
App.Current.Shutdown(); // Just shutdown the current application,if any instance found.
base.OnStartup(e);
}
So with this solution only one instance is allow but in case the user try to open another instance i can see that in the task bar i have new icon of my application, this icon automatically close when the mouse is over but I want to prevent this icon to be show so I remove this from App.xaml:
StartupUri="MainWindow.xaml"
And now my application not started (probably started but i cannot see it).
Any chance to achieve what I want ?
I need to call MainWindow but I don't know from where
UPDATE
So I try this approach:
protected override void OnStartup(StartupEventArgs e)
{
if (SingleInstance.AlreadyRunning())
App.Current.Shutdown(); // Just shutdown the current application,if any instance found.
base.OnStartup(e);
new MainWindow().Show();
}
And still i can see the second (and third and so...) icons when the user try to open another instance