Warn on incompatible wxDirDialog styles

include/wx/dirdlg.h

@@ -88,7 +88,12 @@ public:
     virtual void SetPath(const wxString& path) { m_path = path; }
 
     virtual wxString GetMessage() const { return m_message; }
-    virtual wxString GetPath() const { return m_path; }
+    virtual wxString GetPath() const
+    {
+        wxCHECK_MSG( !HasFlag(wxDD_MULTIPLE), wxString(), "When using wxDD_MULTIPLE, must call GetPaths() instead" );
+        return m_path;
+    }
+
     virtual void GetPaths(wxArrayString& paths) const { paths.Empty(); paths.Add(m_path); }
 
 protected:

interface/wx/dirdlg.h

@@ -122,6 +122,9 @@ public:
 
     /**
         Returns the default or user-selected path.
+
+        @note This function can't be used with dialogs which have the @c wxDD_MULTIPLE style,
+              use GetPaths() instead.
     */
     virtual wxString GetPath() const;
 

src/gtk/dirdlg.cpp

@@ -190,6 +190,7 @@ void wxDirDialog::SetPath(const wxString& dir)
 
 wxString wxDirDialog::GetPath() const
 {
+    wxCHECK_MSG( !HasFlag(wxDD_MULTIPLE), wxString(), "When using wxDD_MULTIPLE, must call GetPaths() instead" );
     return m_paths.Last();
 }
 

src/osx/cocoa/dirdlg.mm

@@ -173,6 +173,7 @@ void wxDirDialog::SetTitle(const wxString &title)
 
 wxString wxDirDialog::GetPath() const
 {
+    wxCHECK_MSG( !HasFlag(wxDD_MULTIPLE), wxString(), "When using wxDD_MULTIPLE, must call GetPaths() instead" );
     return m_paths.Last();
 }