Splash screen does not return focus to main form

问题:

I everyone. I currently have a problem with my focus when using a splash screen. I am using VS2008, with .NET framework 2.0. Also, I have linked my project with the VisualBasic.dll since I use the ApplicationServices to manage my single instance app and splash screen.

Here is a code snippet simplified of what I tried debugging.

namespace MyProject
{
    public class Bootstrap
    {
        /// <summary>
        /// Main entry point of the application. It creates a default 
        /// Configuration bean and then creates and show the MDI
        /// Container.
        /// </summary>
        [STAThread]
        static void Main(string[] args)
        {
            // Creates a new App that manages the Single Instance background work
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            App myApp = new App();
            myApp.Run(args);
        }
    }

    public class App : WindowsFormsApplicationBase
    {
        public App()
            : base()
        {
            // Make this a single-instance application
            this.IsSingleInstance = true;
            this.EnableVisualStyles = true;

            // There are some other things available in the VB application model, for
            // instance the shutdown style:
            this.ShutdownStyle = Microsoft.VisualBasic.ApplicationServices.ShutdownMode.AfterMainFormCloses;

            // Add StartupNextInstance handler
            this.StartupNextInstance += new StartupNextInstanceEventHandler(this.SIApp_StartupNextInstance);
        }

        protected override void OnCreateSplashScreen()
        {
            this.SplashScreen = new MyMainForm();
            this.SplashScreen.StartPosition = FormStartPosition.CenterScreen;
        }
        protected override void OnCreateMainForm()
        {
            // Do your initialization here
            //...
            System.Threading.Thread.Sleep(5000);  // Test
            // Then create the main form, the splash screen will automatically close
            this.MainForm = new Form1();
        }
        /// <summary>
        /// This is called for additional instances. The application model will call this 
        /// function, and terminate the additional instance when this returns.
        /// </summary>
        /// <param name="eventArgs"></param>
        protected void SIApp_StartupNextInstance(object sender,
            StartupNextInstanceEventArgs eventArgs)
        {
            // Copy the arguments to a string array
            string[] args = new string[eventArgs.CommandLine.Count];
            eventArgs.CommandLine.CopyTo(args, 0);

            // Create an argument array for the Invoke method
            object[] parameters = new object[2];
            parameters[0] = this.MainForm;
            parameters[1] = args;

            // Need to use invoke to b/c this is being called from another thread.
            this.MainForm.Invoke(new MyMainForm.ProcessParametersDelegate(
                ((MyMainForm)this.MainForm).ProcessParameters),
                parameters);
        }
    }
}

Now, what happens is that, when I start the application, the Splash Screen shows as expected, but when it is destroyed, it does not return the focus to the main form (Form1 in the test). The MainForm simply flashes orange in the taskbar. If I launch the application from the IDE (VS2008), focus works just fine. I am using XP Pro. Also, the main form is not on top of every other windows. If I comment out the OnCreateSplashScreen() method, the application gets focus normally.

To test normal execution, I am using the VS Command Prompt to launch my application. I am using the Release version of my project.

Any ideas?

Edit: I also handle the StartUpNextInstance event to send my command-line arguments to my main form. For test purposes, it was removed here.

Edit: Added a bit more code. Now you have the full extent of my bootstrap.

回答1:

The question is not in detail.

1) What the is the relationship between the SplashScreen and the main form of the application?

2) How does SplashScreen automatically close?

I'm sure the problem here is that the main form had already started loading up in the background while SplashScreen is yet to close. Due to bad timing, the main form loads up in the background and the SplashScreen unloads... hence the flash in the taskbar.

Make them appear in serial controlled manner. There are many ways. I cannot suggest exactly how since hardly any detail has been provided. Like what is VB doing in the project, how many threads are working, what are the custom forms used here.. etc.

EDIT:

Algorithm to implement Splash screen (IMHO) :)

1) Create a custom form - splash screen

2) Run it on a separate thread. Implement it's behaviour as you like.

3) In your splash screen form, write a handler to capture a custom unload event handler which closes the splash screen form.

4) Now, back in the main thread, create you main app form. Set its Visible property to false.

5) Write even handler of the main form's Load event. In this handler, fire an event to splash screen to unload. Then, make the main form visible.

回答2:

You need to call the Activate() method on your main form in order to display it properly.

回答3:

In some of my implementations of splash forms on a different thread, I've seen this situation as well.

usually if I call this.Activate(); as my first line of code in the form load it tends to work as expected. putting this after hiding the splash usually doesnt work correctly.

other methods that can help.

this.BringToFront();
this.TopMost = true; //setting this to true and back to false sometimes can help

回答4:

What if you set the focus explicitly in your Form1 Load event?

回答5:

For some obscure reason, focus seems to be working correctly. I am going to try and incorporate more of my normal execution of my main program into the MyMainForm and try to find what really causes the focus change to fail. I will keep you all posted.

回答6:

try calling form1.show() after this.MainForm = new Form1(); It worked for me.

回答7:

I had the same issue and wanted easy solution for this.

I tried above but no luck, but ideas from above useful information.

I tried my trick and it works for me.

This is my Programs.cs code which works fine:

static class Program
{
    /// <summary>
    /// The main entry point for the application.
    /// </summary>
    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        var mainWindow = new frmMain();
        splashScreen.DisplaySplashScreen(mainWindow, 10000);
        **mainWindow.TopMost = true;**
        Application.Run(mainWindow);
    }
}

Notice the mainWindow.TopMost = true;

Ok that was working enough but I did not want the mainWindow to stay on top.

So in Shown event i added this.TopMost = false;

    private void frmMain_Shown(object sender, EventArgs e)
    {
        this.TopMost = false;
    }

Now my application is working as I wanted it to work.

Note: Just posted to help any other user who face the same issue what I faced.

Happy Coding :)