Check folder is open or not - vb.net

Question

how should i make this go open folder only if only folder it is not open? the folder should only open if it is not open. and put an if, and an else.
Private Shared Function FindWindow(ByVal lpClassName As String, ByVal lpWindowName As String) As IntPtr
End Function
Dim folderpath As String
Dim foldername As String
'Process.Start(System.Environment.CurrentDirectory)
folderpath = My.Application.Info.DirectoryPath + ("\Check")
foldername = System.IO.Path.GetFileName(folderpath)
If FindWindow(vbNullString, foldername) = 0 Then
Process.Start("explorer.exe", folderpath)
End If

Answer 1

Windows has a function built in to do this. https://learn.microsoft.com/en-us/windows/win32/shell/ishelldispatch-windows and look at the windows property.
When Internet Explorer 4 Desktop Update was released there was no difference between local files and internet files. Therefore it lists Internet Explorer (but no other browser) and Windows Explorer windows.
The win in AllWindows is actually an Internet Explorer object - see https://learn.microsoft.com/en-us/previous-versions/windows/internet-explorer/ie-developer/platform-apis/aa752084(v=vs.85)
'ListOpenShellWindows.vb
Imports System.Runtime.InteropServices
Public Module MyApplication
Sub Main()
Dim ObjShell as Object
Dim AllWindows as Object
objShell = CreateObject("Shell.Application")
AllWindows = objShell.Windows
For Each win in AllWindows
Msgbox(win.LocationUrl & " - " & win.LocationName)
Next
End Sub
End Module
To compile copy both files into same folder and double click the batch file.
REM ListOpenShellWindows.bat
REM This file compiles ListOpenShellWindows.vb to ListOpenShellWindows.exe using the system VB.NET compiler
"C:\Windows\Microsoft.NET\Framework\v4.0.30319\vbc.exe" /target:winexe /out:"%~dp0\ListOpenShellWindows.exe" "%~dp0\ListOpenShellWindows.vb"
pause
Edit
If interacting with the Shell it is best to use the Shell functions. You use ObjShell.Open to open a folder. See https://learn.microsoft.com/en-us/windows/win32/shell/ishelldispatch-open.

Answer 2

If the goal is to not open multiple explorer instances for the same directory, then you can simply pass a new ProcessStartInfo object to the Process.Start(...) function. Assign the directory path to the ProcessStartInfo.FileName property and the "open" command to the ProcessStartInfo.Verb property. This way, an already open instance will be activated rather than opening a new one for the same dir.
' Some caller...
Dim dirInfo = New DirectoryInfo(Path.Combine(My.Application.Info.DirectoryPath, "Check"))
Dim psi As New ProcessStartInfo With {
.FileName = dirInfo.FullName,
.Verb = "open"
}
Process.Start(psi)
On the other hand, if you still need to find out whether a directory is already open in the explorer, then you could pinvoke the FindWindowByCaption function which returns a handle to a window if any.
Dim dirInfo = New DirectoryInfo(Path.Combine(My.Application.Info.DirectoryPath, "Check"))
Dim p = FindWindowByCaption(IntPtr.Zero, dirInfo.Name)
If p = IntPtr.Zero Then
Process.Start(dirInfo.FullName)
Else
Console.WriteLine("Already Open!")
End If
<DllImport("user32.dll", EntryPoint:="FindWindow", SetLastError:=True, CharSet:=CharSet.Auto)>
Private Shared Function FindWindowByCaption(zero As IntPtr, lpWindowName As String) As IntPtr
End Function
Of course, the target directory should exist in the first place. Just in case, see the DirectoryInfo.Exists property and the DirectoryInfo.Create method.