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How to get hidden form from task bar to front in C# winform? From class

I am doing it from a class, because I've got code to make it so only one instance can work. I've seen lots of forums and just cannot figure it out. I've tried all sorts of methods like Application.OpenForms etc, nothing is working. The last form which was closed will be hidden in the taskbar. I just want to be able to bring that hidden form.
namespace EncryptionDecryption
{
static class Program
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
bool instanceCountOne = false;
using (Mutex mtex = new Mutex(true, "MyRunningApp", out instanceCountOne))
{
if (instanceCountOne)
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new Login("", ""));
mtex.ReleaseMutex();
}
else
{
MessageBox.Show("An instance of this application is already running in the taskbar", "Note");
mtex.ReleaseMutex();
Environment.GetCommandLineArgs();
//Trying to pass the loggedinusername and role to new instance of the program so dont have to sign in again...
}
}
}
}

Instead of using the above I used this which plays with threads to make sure I only have one instance and it will open that one instance only with new parameters to! Which i really needed for my next step!
https://social.msdn.microsoft.com/Forums/vstudio/en-US/a5bcfc8a-bf69-4bbc-923d-f30f9ecf5f64/single-instance-application?forum=csharpgeneral

Main window form showing up blank

I've gone through a number of the other questions regarding this issue.
The form loads, but it's missing all its controls. It used to work. Clearly I screwed something up but I cannot figure out what I changed to break it.
I've checked and my UploaderUI.cs is spelled correctly. Its code is below:
namespace uploaderUI
{
static class UploaderUI
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new mainForm());
}
}
}
My InitializeComponent is working, and I am able to set a break point and step through all of it.
public mainForm()
{
InitializeComponent();
// Create an instance of a ListView column sorter and assign
// to the ListView control.
lvwColumnSorter = new ListViewColumnSorter();
this.listViewNotCurrent.ListViewItemSorter = lvwColumnSorter;
}
I'm at a loss, I don't know what else to look for. Not even sure what else to post here that can help.

I encountered the same problem. What I was doing was creating the form on a thread other than the "Main" form UI. This caused the "blank" form issue. Fix it by changing your code or ensuring the form creation happens on the UI thread:
mainForm.Invoke((MethodInvoker)delegate {
new Form();
});

Minimize Windows form on system Start up [duplicate]

This question already has answers here:
How to start WinForm app minimized to tray?
(6 answers)
Closed 8 years ago.
I have developed a windows form application and installer for it. I had installed that app on my machine. Now when I restart my PC or Log in on machine the App gets launched and shown on desktop. A sys tray icon is also shown in sys-tray. Now I want to keep app hidden and only sys tray icon should be visible. Means app should not be displayed on screen but sys tray icon should be visible. I have used "CreateProcessAsCurrentUser" method in which I have set the value of "STARTF_USESHOWWINDOW" to different values. But still its not working. Also I am not getting which method of Application gets called on System startup. Is it Main() function from Program.cs file. Please tell me the solution and also the Function which gets called.
[STAThread]
Main() function code: `static void Main()
{
Mutex mutex = new Mutex(false, "Application Name");
try
{
if (mutex.WaitOne(0, false))
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.ThreadException += new ThreadExceptionEventHandler(Application_ThreadException);
AppDomain.CurrentDomain.UnhandledException += new UnhandledExceptionEventHandler(CurrentDomain_UnhandledException);
Application.Run(new MainForm());
}
else
{
IntPtr pf = NativeMethods.FindWindow(null, "Application Name");
NativeMethods.ShowWindow(pf, 0);
NativeMethods.SetForegroundWindow(pf);
}
}
I have set the value of flag as below.
[Flags]
public enum CreateProcessFlags : uint
{
STARTF_USESHOWWINDOW = 0x00000000,
}

try this.... put this in your form:
protected override void SetVisibleCore(bool value)
{
base.SetVisibleCore(false);
}
this will always now make the form invisible.
you will need some logic though to determine if it should be shown or not from other parts of your app. for example, set a global bool value and modify the code above to use that.
alternatively, you can use this:
protected override void OnVisibleChanged(EventArgs e)
{
base.OnVisibleChanged(e);
this.Visible = false;
}
but you will see a bit of a flash when you run the app straight away. you then, again, need to control when to make it visible so check the global bool value for the visible property so you can eventually display the form

have you try this?
private void Form1_Load(object sender, EventArgs e)
{
this.WindowState = FormWindowState.Minimized;
this.Hide();
this.ShowInTaskbar = true;
}
then use notifyicon

Splash screen to show up in the middle of application

I have a list of report names displayed as Tree hierarchy in ReportViewer control. When user clicks on a report name, an input form loads, user enters some values and presses OK. At this point, Splash screen should load while the backend process is happening (connecting to DB, retrieving values etc). Once the report is loaded in Reportviewer editor, the splashscreen should close.
So far, I am able to display the splash screen however it gets stuck at that point, the actual report does not load and the splash screen stays on forever.
Is it possible to use splashscreen in the middle of application, not at app launch? If so, how do I continue with loading report?
static class Program
{
[STAThread]
static void Main(string[] args)
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new SnapPlusReports());
//new SplashScreenApp().Run(args);
}
}
public class SplashScreenApp : WindowsFormsApplicationBase
{
private static SplashScreenApp _application;
public static void Run(Form form)
{
_application = new SplashScreenApp { MainForm = form };
_application.Run(Environment.GetCommandLineArgs());
}
protected override void OnCreateSplashScreen()
{
this.SplashScreen = new ShowProgress();
base.OnCreateSplashScreen();
}
}

I have done this before by making a new form at run time dynamically with code. Make sure you set all the options up, especially FormBorderStyle to none, or something like that so the user can't close it. Then simply manipulate labels that appear on that form, and eventually close it once your process is complete.
This way you don't have to worry about threading and a nice side effect is that the initial form won't be clickable.
For example I have an about form that pops up during run time (granted I don't change anything on it but the idea is there:
AboutForm aboutForm = new AboutForm();
aboutForm.StartPosition = FormStartPosition.CenterParent;
Label lblAbout = new Label();
Version applicationVersion = System.Reflection.Assembly.GetExecutingAssembly().GetName().Version;
lblAbout.Text = applicationVersion.ToString();
lblAbout.Location = new Point(145,104);
aboutForm.Controls.Add(lblAbout);
aboutForm.ShowDialog();
This shows the current programs version number, etc. There are other labels that already exist on the form (I created it visually first and then called an instance of it).
Hope this helps!

...Catch other instances and gracefully exit if you need only one copy of your app in memory at a given time
static void Main()
{
Application.EnableVisualStyles();
bool exclusive;
System.Threading.Mutex appMutex = new System.Threading.Mutex(true, "MY_APP", out exclusive);
if (!exclusive)
{
MessageBox.Show("Another instance of xxxx xxxBuilder is already running.","MY_APP",
MessageBoxButtons.OK,
MessageBoxIcon.Exclamation );
return;
}
Application.SetCompatibleTextRenderingDefault(false);
xxxWindowsApplication.InitializeApplication();
Application.Run(new frmMenuBuilderMain());
GC.KeepAlive(appMutex);
}
In the main form load you could do something like:
private void frmMenuBuilderMain_Load(object sender, EventArgs e)
{
//Show Splash with timeout Here--
if(!SystemLogin.PerformLogin())
{
this.Close();
return;
}
tmrLoad.Enabled = true;
}

Any way to create a hidden main window in C#?

I just want a c# application with a hidden main window that will process and respond to window messages.
I can create a form without showing it, and can then call Application.Run() without passing in a form, but how can I hook the created form into the message loop?
Is there another way to go about this?
Thanks in advance for any tips!

Excellent! That link pointed me in the right direction. This seems to work:
Form f = new Form1();
f.FormBorderStyle = FormBorderStyle.FixedToolWindow;
f.ShowInTaskbar = false;
f.StartPosition = FormStartPosition.Manual;
f.Location = new System.Drawing.Point(-2000, -2000);
f.Size = new System.Drawing.Size(1, 1);
Application.Run(f);
To keep it from showing up in Alt-Tab, you need it to be a tool window. Unfortunately, this prevents it from starting minimized. But setting the start position to Manual and positioning it offscreen does the trick!

In the process of re-writing a VC++ TaskTray App, in C# .NET, I found the following method truly workable to achieve the following.
No initial form dislayed at startup
Running Message Loop that can be used with Invoke/BeginInvoke as needed as IsWindowHandle is true
The steps I followed:
Used an ApplicationContext in Application.Run() Instead of a form. See http://www.codeproject.com/Articles/18683/Creating-a-Tasktray-Application for the example I used.
Set the Form's ShowInTaskbar property to true within the GUI Designer. (This seems counter productive but it works)
Override the OnLoad() method in your Form Class setting Visible and ShowInTaskbar to false as shown below.
protected override void OnLoad(EventArgs e)
{
Visible = false;
ShowInTaskbar = false;
base.OnLoad(e);
}

I know this is old question, but it ranks well in google, so I will provide my solution anyway.
I do two things:
private void Form_Load(object sender, EventArgs e)
{
Opacity = 0;
}
private void Form_Shown(object sender, EventArgs e)
{
Visible = false;
Opacity = 100;
}

The best way is to use the following 1-2 lines in the constuctor:
this.WindowState = FormWindowState.Minimized;
this.ShowInTaskbar = false; // This is optional
You can even set the Minimized property in the VS Property window.

You can create a class that inherits from System.Windows.Forms.NativeWindow (which provides basic message loop capability) and reference the Handle property in its constructor to create its handle and hook it into the message loop. Once you call Application.Run, you will be able to process messages from it.

I solved the problem like this:
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Main main = new Main();
Application.Run();
//Application.Run(new Main());
}
This code resides in the Program.cs file, and you can see the original Application.Run method call commented out. I just create a Main class object (my main form class is named Main) and start application message loop w/o any parameters. This starts the application, initializes any form components but doesn't show the form.
Note: you have to have some method to get your window showing (like system tray icon, hotkey or timer or anything you might like).

public partial class Form1 : Form
{
private bool _isApplicationRun;
public Form1(bool applicationRun)
{
InitializeComponent();
_isApplicationRun = applicationRun;
}
protected override void SetVisibleCore(bool value)
{
if (_isApplicationRun)
{
_isApplicationRun = false;
base.SetVisibleCore(false);
return;
}
base.SetVisibleCore(value);
}
}
static class Program
{
[STAThread]
static void Main()
{
Application.Run(new Form1(true));
}
}

Why can't you just pass the form when you call Application.Run? Given that it's clearly a blocking call, on what event do you want to show the form? Just calling form.Show() should be enough.

Using Kami's answer as an inspiration, I created a more complete concept. If you use this solution, don't ever show the hidden window. If you do, the user might close it and then you've lost the ability to control the application exit in an orderly way. This approach can be used to manage a Timer, NotifyIcon, or any other component that is happy living on an invisible form.
using System;
using System.Windows.Forms;
namespace SimpleHiddenWinform
{
internal class HiddenForm : Form
{
private Timer _timer;
private ApplicationContext _ctx;
public HiddenForm(ApplicationContext ctx)
{
_ctx = ctx;
_timer = new Timer()
{
Interval = 5000, //5 second delay
Enabled = true
};
_timer.Tick += new EventHandler(_timer_Tick);
}
void _timer_Tick(object sender, EventArgs e)
{
//tell the main message loop to quit
_ctx.ExitThread();
}
}
static class Program
{
[STAThread]
static void Main()
{
var ctx = new ApplicationContext();
var frmHidden = new HiddenForm(ctx);
//pass the application context, not the form
Application.Run(ctx);
}
}
}

Form1 f1=new Form1();
f1.WindowState = FormWindowState.Minimized;
f1.ShowInTaskbar = false;

in the Form1 code file add this.Visible = false; to the constructor.
This will hide the window but it will flash for a sec before it is hidden. Alternatively you can write your own Application.Run command.
for more info http://social.msdn.microsoft.com/forums/en-US/winforms/thread/dece45c8-9076-497e-9414-8cd9b34f572f/
also you may want to set the this.ShowInTaskbar to false.

You should look at creating a 'service' as this is an application without a form.
See http://support.microsoft.com/kb/816169