Help with multi file selection

[desarrollo03TR]

Hi! I need to add the muti selection option. What I did is:

((OpenFileDialog)_MSdialog).Multiselect = this.MultiSelect;

And it is working, but I cannot get the list of selected files when there are 8 or more selected files:

case (uint)DialogChangeStatus.CDN_SELCHANGE:
    StringBuilder filePath = new StringBuilder(256);
    NativeMethods.SendMessage(new HandleRef(this, NativeMethods.GetParent(Handle)), (uint)DialogChangeProperties.CDM_GETFILEPATH, (IntPtr)256, filePath);
    if(_CustomCtrl != null)
    {
        if(_CustomCtrl.MultiSelect)
        {
            // filePath is empty if 8+ files are selected

I've tried with a bigger buffer;

StringBuilder filePath = new StringBuilder(8192);

Or even higher, but I have the same result, an empty string.

[Hoek67]

I had the same problem with multi-select. Finally got it going and once the returned string was >= 255 then... it returned an empty string.

I bumped the stringbuilder buffer up to 2048 and the length parameter to match and it still seems to have the 256 limit.

I noticed the files in the dialog look fine so thinking about doing a nasty hack to get the values I need.

I used the SPY tool and saw the window with the values I need seems to be as expected. Should be able to send a Windows message to it to grab the text.

[Hoek67]

OK... got the fudge working.

Define a few dll entries...

<DllImport("user32.dll")>
Public Shared Function GetWindowText(ByVal hwnd As IntPtr, ByVal lpString As StringBuilder, ByVal cch As Integer) As Integer
End Function

<DllImport("user32.dll")>
Public Shared Function GetWindow(wnd As IntPtr, cmd As Integer) As IntPtr
End Function

Then in the code where the filename changes and it dies after 256 characters add the following.

Private Sub MyOpenFileDialogControl_FileNameChanged(ByVal sender As IWin32Window, ByVal filePath As String) Handles MyBase.EventFileNameChanged

Dim sb As New StringBuilder(2048)
Dim wnd As IntPtr = Me.Handle

For i As Integer = 0 To 8
    wnd = GetWindow(wnd, 2) ' keep grabbing next window until at the one we want
Next

Dim ret As Integer = GetWindowText(wnd, sb, sb.Capacity)
filePath = sb.ToString  ' format is a bit different as 1st element does not have the full path

*** Ended up moving the code into helpertypes.vb ... now working as expected.