wxDataViewTreeCtrl - How to check if a container has child items? Topic is solved

[apoorv569]

I see there is a method in wxDataViewTreeCtrl class to check if a item is a container, I'm wondering if there is a way/method to check if a container has child items in it or not? as I could not find anything.

[doublemax]

wxDataViewTreeCtrl::GetChildCount() ?

[apoorv569]

wxDataViewTreeCtrl::GetChildCount() ?

Ah! Yes, don't know how I missed this.

I also want to know if it is possible to get wxDataViewItem from wxDropFilesEvent, as I want to drag and drop files from wxDataViewListCtrl to wxDataViewTreeCtrl, and the AppendItem() needs a wxDataViewItem& parent. I have enabled DragAcceptFIles(true) on the wxDataViewTreeCtrl.

Code: Select all

void MainFrame::OnDragAndDropToCollectionView(wxDropFilesEvent& event)
{
    if (event.GetNumberOfFiles() > 0)
    {
        wxString* dropped = event.GetFiles();
        wxASSERT(dropped);

        wxString filepath;
        wxArrayString filepath_array;

        for (int i = 0; i < event.GetNumberOfFiles(); i++)
        {
            filepath = dropped[i];

            if (wxFileExists(filepath))
            {
                filepath_array.push_back(filepath);
            }
            // else if (wxDirExists(filepath))
            // {
            //     wxDir::GetAllFiles(filepath, &filepath_array);
            // }
        }

	wxDataViewItem selected = m_CollectionView->GetSelection();

	for(int i = 0; i < event.GetNumberOfFiles(); i++)
	  m_CollectionView->AppendItem(selected, filepath_array[i].AfterLast('/'));
    }
}

But this m_CollectionView->GetSelection() always just drops it on outside of any container.

[AmadeusK525]

Hello,
AFAIK wxDataViewListCtrls and wxDataViewTreeCtrls handle their wxDataViewItems differently: the former uses wxDataViewListStore and the latter uses wxDataViewTreeStore, so I suspect that, even if you manage to get the wxDataViewItem (which is just a memory address, what handles the data is the wxDataViewModel), trying to add it to a different kind of wxDataViewCtrl may have unexpected behavior. Well, even so, if you handle the wxDataViewCtrl drag and drop events (wxEVT_DATAVIEW_ITEM_BEGIN_DRAG, wxEVT_DATAVIEW_ITEM_DROP_POSSIBLE and wxEVT_DATAVIEW_ITEM_DROP), this may be possible using wxDataViewEvent::GetProposedIndex() and then wxDataViewListCtrl::RowToItem(). Using these events is demonstrated in the wxDataViewCtrl sample, although it's limited to the same wxDataViewCtrl, so I'm not sure if they'll be fired when trying to send a wxDataViewItem from one control to another.

[apoorv569]

Hello,
AFAIK wxDataViewListCtrls and wxDataViewTreeCtrls handle their wxDataViewItems differently: the former uses wxDataViewListStore and the latter uses wxDataViewTreeStore, so I suspect that, even if you manage to get the wxDataViewItem (which is just a memory address, what handles the data is the wxDataViewModel), trying to add it to a different kind of wxDataViewCtrl may have unexpected behavior. Well, even so, if you handle the wxDataViewCtrl drag and drop events (wxEVT_DATAVIEW_ITEM_BEGIN_DRAG, wxEVT_DATAVIEW_ITEM_DROP_POSSIBLE and wxEVT_DATAVIEW_ITEM_DROP), this may be possible using wxDataViewEvent::GetProposedIndex() and then wxDataViewListCtrl::RowToItem(). Using these events is demonstrated in the wxDataViewCtrl sample, although it's limited to the same wxDataViewCtrl, so I'm not sure if they'll be fired when trying to send a wxDataViewItem from one control to another.

Thanks for the response, I don't want to get the wxDataViewListCtrl item to wxDataViewTreeCtrl, what I mean by how to get the wxDataViewItem is, as in when the user drag a file from wxDataViewListCtrl, and tries to drop it on wxDataViewTreeCtrl, I want to get the wxDataViewItem on which container the user drops the file on, so I can add the file(filename) to that container. I'm not trying transfer memory address. I basically get the info of the item that is being dragged from wxDataViewListCtrl, from the Sqlite database, such as filename, sample rate, path and all and I want to insert the filename to whatever container the file drops on. I'm using wxDataViewTreeCtrl as sort of a folder-file directory thing, container as folder, files as child items.

[doublemax]

Get the position from the event, then wxDataViewCtrl::HitTest() to find the item at that position.

[AmadeusK525]

I basically get the info of the item that is being dragged from wxDataViewListCtrl, from the Sqlite database, such as filename, sample rate, path and all and I want to insert the filename to whatever container the file drops on.

Oh okay, sorry for the mix-up!

[apoorv569]

Get the position from the event, then wxDataViewCtrl::HitTest() to find the item at that position.

The HitTest() take wxPoint& point, wxDataViewItem& item and wxDataViewColumn*& column. The wxPoint& point will take event.GetPosition(), but what do I put in place of wxDataViewItem& item and wxDataViewColumn*& column?

[apoorv569]

Get the position from the event, then wxDataViewCtrl::HitTest() to find the item at that position.

Okay, I found this post here -viewtopic.php?t=37775

I tried this and it works now. Thank you for the help.

Here is the code might help someone else in future.

Code: Select all

void MainFrame::OnDragAndDropToCollectionView(wxDropFilesEvent& event)
{
    if (event.GetNumberOfFiles() > 0)
    {
        wxString* dropped = event.GetFiles();
        wxASSERT(dropped);

        // wxBusyCursor busy_cursor;
        // wxWindowDisabler window_disabler;

        wxString filepath;
        wxArrayString filepath_array;

        for (int i = 0; i < event.GetNumberOfFiles(); i++)
        {
            filepath = dropped[i];

            if (wxFileExists(filepath))
            {
                filepath_array.push_back(filepath);
            }
            // else if (wxDirExists(filepath))
            // {
            //     wxDir::GetAllFiles(filepath, &filepath_array);
            // }
        }

	wxDataViewItem selected;
	wxDataViewColumn* column;
	wxPoint position = event.GetPosition();
	
	m_CollectionView->HitTest(position, selected, column);

	for(int i = 0; i < event.GetNumberOfFiles(); i++)
	{
	  wxLogDebug("Dropping %s on folder: %s", filepath_array[i].AfterLast('/'), m_CollectionView->GetItemText(selected));
	  m_CollectionView->AppendItem(selected, filepath_array[i].AfterLast('/'));
	}
    }
}

[apoorv569]

Get the position from the event, then wxDataViewCtrl::HitTest() to find the item at that position.

This works, but I'm only able to drag and drop one item at a time, if I select multiple items from wxDataViewListCtrl and try to drop them on wxDataViewTreeCtrl only the item I clicked on to drag gets added and it ignores the rest, event.GetNumberOfFiles() also returns 1. Is there a way to drag and drop multiple items at once.

[doublemax]

Get the position from the event, then wxDataViewCtrl::HitTest() to find the item at that position.

This works, but I'm only able to drag and drop one item at a time, if I select multiple items from wxDataViewListCtrl and try to drop them on wxDataViewTreeCtrl only the item I clicked on to drag gets added and it ignores the rest, event.GetNumberOfFiles() also returns 1. Is there a way to drag and drop multiple items at once.

This is something you must handle when the drag operation starts. You must iterate over all selected items and add all filenames to the wxFileDataObject

[apoorv569]

This is something you must handle when the drag operation starts. You must iterate over all selected items and add all filenames to the wxFileDataObject

Okay I changed the code, it is working, but it only detects that I'm dragging multiple files if I hold CTRL and then drag the selected items, but clicking CTRL first time deselects the file I start dragging on, so I have to reselect the file while holding CTRL, only then it takes all files. Is this behavior expected or something is wrong?


Here is the code,

Code: Select all

void MainFrame::OnDragAndDropToCollectionView(wxDropFilesEvent& event)
{
    if (event.GetNumberOfFiles() > 0)
    {
        wxFileDataObject file_data;
        wxArrayString files;

	wxDataViewItemArray items;
	int rows = m_SampleListView->GetSelections(items);

        wxDataViewItem selected;
        wxDataViewColumn* column;
        wxPoint position = event.GetPosition();
        m_CollectionView->HitTest(position, selected, column);

	for(int i = 0; i < rows; i++)
	{
	    int row = m_SampleListView->ItemToRow(items[i]);
	    wxString name = m_SampleListView->GetTextValue(row, 1);

	    file_data.AddFile(name);

            files = file_data.GetFilenames();

            wxLogDebug("Dropping %d files.", rows);
	    wxLogDebug("Dropping %s on folder: %s", files[i], m_CollectionView->GetItemText(selected));

	    m_CollectionView->AppendItem(selected, files[i]);
	}
    }
}

[doublemax]

I guess you have some other event handlers on the wxDVC that disturb the selection behavior. When you have multiple files selected, click any of them and keep the button pressed. The selection should not change until you release the mouse. If it behaves differently, check your other event handlers and what they do.

[apoorv569]

I guess you have some other event handlers on the wxDVC that disturb the selection behavior. When you have multiple files selected, click any of them and keep the button pressed. The selection should not change until you release the mouse. If it behaves differently, check your other event handlers and what they do.

Yes actually, I also have this event handler for wxDataViewListCtrl, that handles dragging and dropping a file outside of the application, to like a audio player or file manager or something. Here is the code

Code: Select all

void MainFrame::OnDragFromSampleView(wxDataViewEvent& event)
{
    int selected_row = m_SampleListView->ItemToRow(event.GetItem());

    if (selected_row < 0) return;

    wxString selection = m_SampleListView->GetTextValue(selected_row, 1);

    wxString sample_path = GetFileNamePathAndExtension(selection).Path;

    wxFileDataObject* fileData = new wxFileDataObject();

    fileData->AddFile(sample_path);
    event.SetDataObject(fileData);

    wxLogDebug("Started dragging '%s'.", sample_path);
}

And when do I try to drag and drop on wxDataViewTreeCtrl, it does print this debug statement, "Started dragging ...", could this be doing something wrong?

[doublemax]

If this is a wxEVT_DATAVIEW_ITEM_BEGIN_DRAG handler, it should be fine.