Alt-Tab to another window using VB.Net

Question

Hi,

I was wondering whether it is possible to, at a button click event, to say bring up another window that is running at the same time.

I have a windows app, which is the ... sort of main app and there is another app which has a singular window displayed. From the main app, i want to click a button and bring the other app into focus.

I've tried to use things like System.Diagnostics.ProcessStartInfo to get a handle on the process and tried to do a process.windowstyle = normal, but i still seem to have to alt-tab to that window.

Is there another way of bringing up the window?

Thanks

Answer 1

Code Snippet

Imports System.Runtime.InteropServices

Public Class Form1

    <DllImport("user32")> _
    Private Shared Function SetForegroundWindow(ByVal hWnd As IntPtr) As Boolean
    End Function

    <DllImport("user32", CharSet:=CharSet.Ansi)> _
    Private Shared Function FindWindow( _
    <MarshalAs(UnmanagedType.LPStr)> ByVal className As String, _
    <MarshalAs(UnmanagedType.LPStr)> ByVal windowName As String) As IntPtr
    End Function

    Private Sub Form1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Click
        ' Find instances of calculator
        For Each p As Process In Process.GetProcessesByName("calc")
            ' Get the handle (process.handle is the process handle,
            ' we want the window handle).
            Dim hCalc As IntPtr = IntPtr.Zero
            ' Use Spy++ to find the Class name.
            ' Window name is what is displayed in the windows title bar.
            hCalc = FindWindow("SciCalc", "Calculator")
            If hCalc = IntPtr.Zero Then
                MessageBox.Show("didn't find calculator (scientific mode)")
                Exit Sub
            End If
            If SetForegroundWindow(hCalc) = False Then
                MessageBox.Show("SetForegroundWindow failed 8(")
            End If
        Next
    End Sub

End Class

 

 

Answer 2

I use the following to switch between main application and another window.

 

this only really works if the other window is the only other application running as it is *very* basic..

 

Code Snippet

SendKeys.Send("%{TAB}")

 

 

Answer 3

Jo0ls:
Thanks for that. it does work...but not if the other window has a window state of minimized. I do try to set the windostate to normal, using the System.Diagnostics.ProcessStartInfo class to set the ProcessWindowStyle to Normal, but that doesnt seem to get it up. It still stays minimized. Can i set it to normal using the window handle?

Answer 4

 

Looks like you need 2 api calls then, one to restore it, and one to bring it to the foreground:

 

Code Snippet

Imports System.Runtime.InteropServices

Public Class Form1

    Const SW_SHOWNORMAL = 1

    <DllImport("user32")> _
    Private Shared Function ShowWindow(ByVal hWnd As IntPtr, ByVal showCommand As Integer) As Boolean
    End Function

    <DllImport("user32")> _
    Private Shared Function SetForegroundWindow(ByVal hWnd As IntPtr) As Boolean
    End Function

    <DllImport("user32", CharSet:=CharSet.Ansi)> _
    Private Shared Function FindWindow( _
    <MarshalAs(UnmanagedType.LPStr)> ByVal className As String, _
    <MarshalAs(UnmanagedType.LPStr)> ByVal windowName As String) As IntPtr
    End Function

    Private Sub Form1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Click
        ' Find instances of calculator
        For Each p As Process In Process.GetProcessesByName("calc")
            ' Get the handle (process.handle is the process handle,
            ' we want the window handle).
            Dim hCalc As IntPtr = IntPtr.Zero
            ' Use Spy++ to find the Class name.
            ' Window name is what is displayed in the windows title bar.
            hCalc = FindWindow("SciCalc", "Calculator")
            If hCalc = IntPtr.Zero Then
                MessageBox.Show("didn't find calculator (scientific mode)")
                Exit Sub
            End If
            If ShowWindow(hCalc, SW_SHOWNORMAL) = False Then
                MessageBox.Show("ShowWindow failed 8(")
            End If
            If SetForegroundWindow(hCalc) = False Then
                MessageBox.Show("SetForegroundWindow failed 8(")
            End If
        Next
    End Sub

End Class

 

 

Answer 5

Cool...thanks for that guys!! Really appreciated.

Answer 6

one day i was working in console application & i don't know what happened suddenly