wxPropertyGrid::ChangePropertyValue not work Topic is solved

[Ronald]

demo in attachment
It's a VS2019 solution, easy to migrate.

ShowBug.VS2019.7z

(3.91 KiB) Downloaded 45 times

main code

Code: Select all

#include "pch.h"
#include "BuggyPropGrid.h"

BEGIN_EVENT_TABLE(BuggyPropGrid, wxPropertyGrid)
EVT_PG_CHANGED(wxID_ANY, BuggyPropGrid::OnPropChanged)
EVT_PG_DOUBLE_CLICK(wxID_ANY, BuggyPropGrid::OnPGDClick)
END_EVENT_TABLE()

BuggyPropGrid::BuggyPropGrid(wxWindow * parent,
                                   wxWindowID id,
                                   const wxPoint & pos,
                                   const wxSize & size,
                                   long style,
                                   const wxString & name) :
    wxPropertyGrid(parent, id, pos, size, style, name)
{
    Init();
}

void BuggyPropGrid::Init()
{
    _pProp_0 = new wxStringProperty(L"Prop_0");
    _pProp_0->SetValue(5);
    Append(_pProp_0);

    _pProp_1 = new wxStringProperty(L"Prop_1");
    Append(_pProp_1);

    _pProp_2 = new wxStringProperty(L"Prop_2");
    Append(_pProp_2);

    FitColumns();
    
    SetSize(250, 200);
}

void BuggyPropGrid::OnPropChanged(wxPropertyGridEvent & event)
{
    wxPGProperty * pProp = event.GetProperty();
    if (pProp == _pProp_1)
    {
        wxString s = _pProp_1->GetValueAsString();
        double n;
        if (s.ToDouble(&n))
        {
            n *= 2;
            bool ok = ChangePropertyValue(_pProp_2, n); // This line will be executed and return true, but UI doesn't change.
                                                        // wxPropertyGrid::SetPropertyValue works
                                                        // wxPGProperty::SetValue  works
                                                        // But these two doesn't emit change event
            wxASSERT(ok);
        }
    }
}

void BuggyPropGrid::OnPGDClick(wxPropertyGridEvent & event)
{
    unsigned int col = event.GetColumn();
    if (col == 1)
    {
        wxPGProperty * pProp = event.GetProperty();
        if (pProp == _pProp_0)
        {
            ChangePropertyValue(_pProp_1, _pProp_0->GetValue());
        }
    }
}

[doublemax]

This looks like a bug indeed. It works if you use CallAfter for the inner method call:

Code: Select all

if (s.ToDouble(&n))
{
    n *= 2;
    CallAfter([=] {
      bool ok = ChangePropertyValue(_pProp_2, n ); // This line will be executed and return true, but UI doesn't change.
                                                  // wxPropertyGrid::SetPropertyValue works
                                                  // wxPGProperty::SetValue  works
                                                  // But these two doesn't emit change event
      wxASSERT(ok);
    });
}

The problem occurs if you make a ChangePropertyValue call from inside a EVT_PG_CHANGED event handler. I traced through the code a bit and it seems it uses a single m_inDoPropertyChanged flag to remember if the value has already been changed. This is set by the first ChangePropertyValue call and when the second ChangePropertyValue happens, the value will not be updated because this flag is still true.

[Ronald]

This looks like a bug indeed. It works if you use CallAfter for the inner method call:

Code: Select all

if (s.ToDouble(&n))
{
    n *= 2;
    CallAfter([=] {
      bool ok = ChangePropertyValue(_pProp_2, n ); // This line will be executed and return true, but UI doesn't change.
                                                  // wxPropertyGrid::SetPropertyValue works
                                                  // wxPGProperty::SetValue  works
                                                  // But these two doesn't emit change event
      wxASSERT(ok);
    });
}

The problem occurs if you make a ChangePropertyValue call from inside a EVT_PG_CHANGED event handler. I traced through the code a bit and it seems it uses a single m_inDoPropertyChanged flag to remember if the value has already been changed. This is set by the first ChangePropertyValue call and when the second ChangePropertyValue happens, the value will not be updated because this flag is still true.

Yes, I think so, a little complicated.
Thank you very much.
I think I should debug it myself, but my hard disk is not so large now, the wx source code is on another machine, I must buy a large harddisk for open source

[doublemax]

Are you going to open a ticket for this?

[Ronald]

Are you going to open a ticket for this?

OK, to see how fast it will be fixed.
Only if it is not fast enough, or I'll try to do a Pull Request, then I'll really open the source