Kelly's Chronicles

For a particular assignment I had at GE, it was required to determine if a particular form was already open and if so prevent that form from being opened again. The funny thing was I ended up not using it because I went with a simpler solution of using a boolean that was assigned as true if the form was opened then to false when closed. But I spent time on it so hopefully it will help you too. It detects the name of the form, the name of the app, the name of the process id.

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Private Declare Function GetForegroundWindow Lib "user32.dll" () As IntPtr
    Private Declare Function GetWindowThreadProcessId Lib "user32.dll" (ByVal hwnd As IntPtr, ByRef lpdwProcessID As Integer) As Integer
    Private Declare Function GetWindowText Lib "user32.dll" Alias "GetWindowTextA" (ByVal hWnd As IntPtr, ByVal WinTitle As String, ByVal MaxLength As Integer) As Integer
    Private Declare Function GetWindowTextLength Lib "user32.dll" Alias "GetWindowTextLengthA" (ByVal hwnd As Long) As Integer

    Private Sub timerActiveWindowCheck_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles timerActiveWindowCheck.Tick

        ‘—– Get the Handle to the Current Forground Window —–

        Dim hWnd As IntPtr = GetForegroundWindow()

        If hWnd = IntPtr.Zero Then Exit Sub

        ‘—– Find the Length of the Window’s Title —–

        Dim TitleLength As Integer

        TitleLength = GetWindowTextLength(hWnd)

        ‘—– Find the Window’s Title —–

        Dim WindowTitle As String = StrDup(TitleLength + 1, "*")

        GetWindowText(hWnd, WindowTitle, TitleLength + 1)

        ‘—– Find the PID of the Application that Owns the Window —–

        Dim pid As Integer = 0

        GetWindowThreadProcessId(hWnd, pid)

        If pid = 0 Then Exit Sub

        ‘—– Get the actual PROCESS from the process ID —–

        Dim proc As Process = Process.GetProcessById(pid)

        If proc Is Nothing Then Exit Sub

        txtProcessID = pid.ToString

        txtProcessName = proc.ProcessName

        txtProcessTitle = proc.MainWindowTitle

        txtCurrentWindowTitle = WindowTitle

        txtTitleLength = TitleLength.ToString

    End Sub

Technorati Tags: vb.net,csharp,.NET Framework,Window,Find,Active,Form,Alias,WinTitle,System,Tick,Title,TitleLength,WindowTitle,Application,GetProcessById,ProcessName,MainWindowTitle,hwnd,proc

Windows Live Tags: vb.net,csharp,.NET Framework,Window,Find,Active,Form,Alias,WinTitle,System,Tick,Title,TitleLength,WindowTitle,Application,GetProcessById,ProcessName,MainWindowTitle,hwnd,proc