vb.net 2010 edit on looking for valid directory path

In an existing vb.net 2010 desktop application, I want to remove the hardcoded directory paths that are contained within the entire application and obtain the values from a app.config file instead. Right now in the Global.vb program, I have the following code and it works fine as long as the directory path supplied in the app.config file is correct.

Code:

---

#Region "Oledb Connect"
Imports System
Imports System.Collections.Generic
Imports System.IO.Path
Imports System.Configuration.ConfigurationManager
#End Region

Module [Global]
    Public _strDirectoryPath As String = ConfigurationManager.AppSettings("File_directory_path")
    Public dirAccessFiles As String() = Directory.GetFiles(_strDirectoryPath, "*.accdb")
End Module

---

However when there is an error, I have a coding problem. I basically want to check to see if the directory file exists before startup form is loaded. I want to have an if test like what is located in the directory path of: https://msdn.microsoft.com/en-us/lib...v=vs.110).aspx, but the global.vb program will not allow me to have an 'if' test coded. Thus can you tell me what I can do to be able to add the if test to see if the directory exists?

Here is the code from the startup project file if it helps to explain what else I need to change:

Code:

---

#Region " Global Form "
 
    Private Shared m_GlobalForm As frmMain
    Public Shared Property GlobalForm() As frmMain
        Get
            If m_GlobalForm Is Nothing OrElse m_GlobalForm.IsDisposed Then
                m_GlobalForm = New frmMain
            End If
        Return m_GlobalForm
        End Get
        Set(ByVal Value As frmMain)
            m_GlobalForm = Value
        End Set
    End Property
#End Region
   
    Private Sub frmMain_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        frmMain.GlobalForm = Me
    End Sub

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You cannot have an IF function inside a config file, as it is merely XML. You will have to read the path from your config file, check if the path is valid ( from your form ) based on that, display the appropriate form. You could even check the validity inside the New Constructor of your form you'd like to show.

PS, please remember Code tags next time