How to locate the window using findwindow function in windowapi using vba?

Question

I am currently trying to find a way to check whether a window is open or not using Findwindow Function. I am able to find the window if i know the entire name of the window. In the below code i know that the name of the window is "win32api - Notepad" so i can easily find the window however i want to know whether it is possible to identify the window if i know only part name like "win32*".

Public Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long

Sub runapplication()


hwnd = FindWindow(vbNullString, "win32api - Notepad")
MsgBox (hwnd)
End Sub

Answer 1

One way you can do this is with the EnumWindows API function. Since it operates via a callback function, you'll need to cache both the criteria and the results somewhere that has scope beyond the calling function:

Public Declare Function EnumWindows Lib "user32" (ByVal lpEnumFunc As Long, _
                                                  ByVal param As Long) As Long
Public Declare Function IsWindowVisible Lib "User32" (ByVal hWnd As Long) As Long
Public Declare Function GetWindowText Lib "user32" Alias "GetWindowTextA" _
                                                 (ByVal hwnd As Long, _
                                                  ByVal lpString As String, _
                                                  ByVal cch As Long) As Long
Public Const MAX_LEN = 260

Public results As Dictionary
Public criteria As String

Public Sub Example()
    criteria = "win32*"
    Set results = New Dictionary
    Call EnumWindows(AddressOf EnumWindowCallback, &H0)
    Dim result As Variant
    For Each result In results.Keys
        Debug.Print result & " - " & results(result)
    Next result
End Sub

Public Function EnumWindowCallback(ByVal hwnd As Long, ByVal param As Long) As Long
    Dim retValue As Long
    Dim buffer As String       
    If IsWindowVisible(hwnd) Then
        buffer = Space$(MAX_LEN)
        retValue = GetWindowText(hwnd, buffer, Len(buffer))
        If retValue Then
            If buffer Like criteria Then
                results.Add hwnd, Left$(buffer, retValue)
            End If
        End If
    End If
    EnumWindowCallback = 1
End Function

Answer 2

The below code worked for me. Just Declared IsWindowVisible Function and Added Microsoft scripting runtime library to my project.

Public Declare Function EnumWindows Lib "User32" (ByVal lpEnumFunc As Long, _
                                                  ByVal param As Long) As Long
Public Declare Function GetWindowText Lib "User32" Alias "GetWindowTextA" _
                                                 (ByVal hWnd As Long, _
                                                  ByVal lpString As String, _
                                                  ByVal cch As Long) As Long
Public Declare Function IsWindowVisible Lib "User32" (ByVal hWnd As Long) As Long
Public Const MAX_LEN = 260

Public results As Dictionary
Public criteria As String

Public Sub Example()
    criteria = "win32"
    Set results = New Dictionary
    Call EnumWindows(AddressOf EnumWindowCallback, &H0)
    Dim result As Variant
    For Each result In results.Keys
        Debug.Print result & " - " & results(result)
    Next result
End Sub

Public Function EnumWindowCallback(ByVal hWnd As Long, ByVal param As Long) As Long
    Dim retValue As Long
    Dim buffer As String
    If IsWindowVisible(hWnd) Then
        buffer = Space$(MAX_LEN)
        retValue = GetWindowText(hWnd, buffer, Len(buffer))
        If retValue Then

            If InStr(1, buffer, criteria, vbTextCompare) > 0 Then
                results.Add hWnd, Left$(buffer, retValue)
            End If
        End If
    End If
    EnumWindowCallback = 1
End Function