OK, try this.
Code:
Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged
Try
Dim PathPattern As String = "^(([a-zA-Z]:|\\)\\)?(((\.)|(\.\.)|([^\\/:\*\?""\|<>\. ](([^\\/:\*\?""\|<>\. ])|([^\\/:\*\?""\|<>]*[^\\/:\*\?""\|<>\. ]))?))\\)*[^\\/:\*\?""\|<>\. ](([^\\/:\*\?""\|<>\. ])|([^\\/:\*\?""\|<>]*[^\\/:\*\?""\|<>\. ]))?$"
If System.Text.RegularExpressions.Regex.IsMatch(TextBox1.Text, PathPattern) Then
Debug.Print("True")
Else
Debug.Print("False")
End If
Catch ex As Exception
Debug.Print("Exception")
End Try
End Sub