Using API to set focus to application

**Killer42** · Jul 26 '07, 01:30 AM

Originally posted by Martin2007

I'm trying to use SendKeys to control an application, however it keeps losing focus when i call it, cuold anyone tell me how to set the focus to the window using the API? (Visual Basic 2005 Express)

Not sure you need to use the API. I don't know about 2005, but in VB6 there's an AppActivate statement which sets focus to another window. Perhaps you can use that?

**chezz** · Jul 26 '07, 03:00 AM

I know that vb 6 that if u have a text box or something you can do this

Code:

TextBox.SetFocus

This places the focus on the specified object in this case the text box.

It should be something similar to vb 2005

**Killer42** · Jul 26 '07, 04:01 AM

I assumed we were talking about setting the focus to another application. I could be wrong, of course.

**hariharanmca** · Jul 26 '07, 04:34 AM

Originally posted by Martin2007

Hi,

I'm trying to use SendKeys to control an application, however it keeps losing focus when i call it, cuold anyone tell me how to set the focus to the window using the API?

Cheers

(Visual Basic 2005 Express)

can you explain

Why and what exactly you want to do? (if no problem, you can post what you had tried. Because, we are not getting your problem properly).

**Martin2007** · Jul 26 '07, 07:37 AM

Thanks for all the replies...

I'm trying to control a second application from my own VB 2005 project... In an ideal world i would like it to happen all in the background.

Basically i create a new instance of an applicaiton, use sendkeys to make it open a new command file, then again to force it to execute the command file, however when it opens it can often lose focus, so i wanted a call (i thought to the api) to ensure that the window is focused.

I originally wrote this in vb for applications and used the appactiviate with success, but unfortunately I can't find a direct replacement for it in 2005.

This is my code to launch and control the application...

Code:

     Private Sub launchApplication()
        Dim Application As Process = New Process()
        Me.WindowState = FormWindowState.Minimized
       Application.StartInfo.FileName = sPath & "\Application.exe"
       Application.StartInfo.WindowStyle = _
           ProcessWindowStyle.Maximized
        Try
            Application.Start()
        Catch ex As Exception
            Me.WindowState = FormWindowState.Normal
            Err.Raise(53)
        End Try
        Application.WaitForInputIdle(4000)
        SendKeys.Send("%F")
        SendKeys.Send("O")
        SendKeys.Flush()
        Application.WaitForInputIdle(100)
        SendKeys.SendWait(sPath & "\" & commandFileName)
        SendKeys.Flush()
        SendKeys.SendWait("~")
        SendKeys.Flush()
        SendKeys.SendWait("%FE")
        Application.WaitForExit(60000)
        If Not Application.HasExited Then
            Application.Kill()
        End If
        Me.WindowState = FormWindowState.Normal
        MsgBox("Done")
    End Sub

As I said above, in an ideal world I would like the application to never appear (as it requires no user input), my second question is to ask can you launch the application hidden and set the focus to it? (i know u can launch with the startup info set to hidden, just wondering if it is possible to focus to an invisible window)

Thanks for all the help guys!

**hariharanmca** · Jul 26 '07, 10:25 AM

Originally posted by Martin2007

Thanks for all the replies...

I'm trying to control a second application from my own VB 2005 project... In an ideal world i would like it to happen all in the background.

Basically i create a new instance of an applicaiton, use sendkeys to make it open a new command file, then again to force it to execute the command file, however when it opens it can often lose focus, so i wanted a call (i thought to the api) to ensure that the window is focused.

I originally wrote this in vb for applications and used the appactiviate with success, but unfortunately I can't find a direct replacement for it in 2005.

This is my code to launch and control the application...

Code:

     Private Sub launchApplication()
        Dim Application As Process = New Process()
        Me.WindowState = FormWindowState.Minimized
       Application.StartInfo.FileName = sPath & "\Application.exe"
       Application.StartInfo.WindowStyle = _
           ProcessWindowStyle.Maximized
        Try
            Application.Start()
        Catch ex As Exception
            Me.WindowState = FormWindowState.Normal
            Err.Raise(53)
        End Try
        Application.WaitForInputIdle(4000)
        SendKeys.Send("%F")
        SendKeys.Send("O")
        SendKeys.Flush()
        Application.WaitForInputIdle(100)
        SendKeys.SendWait(sPath & "\" & commandFileName)
        SendKeys.Flush()
        SendKeys.SendWait("~")
        SendKeys.Flush()
        SendKeys.SendWait("%FE")
        Application.WaitForExit(60000)
        If Not Application.HasExited Then
            Application.Kill()
        End If
        Me.WindowState = FormWindowState.Normal
        MsgBox("Done")
    End Sub

As I said above, in an ideal world I would like the application to never appear (as it requires no user input), my second question is to ask can you launch the application hidden and set the focus to it? (i know u can launch with the startup info set to hidden, just wondering if it is possible to focus to an invisible window)

Thanks for all the help guys!

Hi Martin2007,
1. This will happen if your code does not refer any event handling.
2. If it refers, it won’t be invisible.
3. If the window is accessing in invisible mode then your mouse pointer will not give command to other application.
4. That other application should controlled by your application (That app. should not have event Control).
5. if we consider that it happens, your application will send some key, if you press any key which is going to operate other application.

I am not sure with your code. But just think your code is satisfy my above Query?

**Martin2007** · Jul 26 '07, 10:30 AM

Originally posted by hariharanmca

Hi Martin2007,
1. This will happen if your code does not refer any event handling.
2. If it refers, it won’t be invisible.
3. If the window is accessing in invisible mode then your mouse pointer will not give command to other application.
4. That other application should controlled by your application (That app. should not have event Control).
5. if we consider that it happens, your application will send some key, if you press any key which is going to operate other application.

I am not sure with your code. But just think your code is satisfy my above Query?

i'm a little new to this, so i'm not sure I understand... but i will try.

my application does not need any event handling from the other application, it just needs to set it running, which i think u say means it can be invisible?

the idea is that the user does not press any keys while the other application is launched, and once it has started to execute the other application will not respond to keypresses anyway. Basically the user presses a button in my application, a message box pops up saying that the other application is running, please wait.. then my application continues on... there is no interface once the other application has been stared.

**hariharanmca** · Jul 26 '07, 10:43 AM

Originally posted by Martin2007

i'm a little new to this, so i'm not sure I understand... but i will try.

my application does not need any event handling from the other application, it just needs to set it running, which i think u say means it can be invisible?

the idea is that the user does not press any keys while the other application is launched, and once it has started to execute the other application will not respond to keypresses anyway. Basically the user presses a button in my application, a message box pops up saying that the other application is running, please wait.. then my application continues on... there is no interface once the other application has been stared.

Originally posted by Martin2007

the idea is that the user does not press any keys while the other application is launched, and once it has started to execute the other application will not respond to keypresses anyway.

then why you want, your application invisible? (As you told, Other App. will not work (Events), when your App. is started.)

Originally posted by Martin2007

Basically the user presses a button in my application, a message box pops up saying that the other application is running, please wait.. then my application continues on...

If your App. is invisible(User dont know your App. is running). then how can you say other App. is Running(in Message Box).

Originally posted by Martin2007

there is no interface once the other application has been stared.

Then what is the necessary to make all this commands.

Just go through what is your requirement.
I think, you are not aware of what you are going to do.

**Martin2007** · Jul 26 '07, 11:27 AM

I dont think you understand me... i will try to be clear.

My application is visible, and allways needs to be...

I need to send commands to a second application to make it do something...

The second application (not my own) needs to be hidden from view, it just needs to run then close (which it will do)...

Basically i need to open the other application, send it a sequency of keystrokes, then leave it alone...

Hope this clarifies...

**hariharanmca** · Jul 26 '07, 12:33 PM

Originally posted by Martin2007

I dont think you understand me... i will try to be clear.

My application is visible, and allways needs to be...

I need to send commands to a second application to make it do something...

The second application (not my own) needs to be hidden from view, it just needs to run then close (which it will do)...

Basically i need to open the other application, send it a sequency of keystrokes, then leave it alone...

Hope this clarifies...

is your above code is working fine? then you carry On.

Originally posted by Martin2007

As I said above, in an ideal world I would like the application to never appear (as it requires no user input), my second question is to ask can you launch the application hidden and set the focus to it? (i know u can launch with the startup info set to hidden, just wondering if it is possible to focus to an invisible window)

You mention this, there the problem start for us.

**Killer42** · Jul 28 '07, 12:50 AM

Martin2007, it looks as though you used the Report button instead of the Reply button. (A mistake I think we've all made from time to time.)

Please send again.

**Martin2007** · Jul 31 '07, 12:45 PM

Originally posted by Killer42

Martin2007, it looks as though you used the Report button instead of the Reply button. (A mistake I think we've all made from time to time.)

Please send again.

Sorry for the report...

The code above does work fine... some of the time... that is the problem which I have been trying to communicate to you.

back to my original question.... can you use the API to force the focus onto an application while it is not visible... that is all i ask... thanks..

**Killer42** · Jul 31 '07, 10:26 PM

Originally posted by Martin2007

back to my original question.... can you use the API to force the focus onto an application while it is not visible... that is all i ask... thanks..

My guess would be... minimised, yes. Invisible, probably not.
Don't know, though. This might be a question for the Windows forum, as it's not specific to VB and we don't seem to have the answer.

Using API to set focus to application

Using API to set focus to application

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