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c++eventsvisual-c++keyboardwxwidgets

Function call error when pressing a keyboard key (WxWidgets)

There is an application on WxWidgets: enter image description here

The same function is called in the code by two ways:

  1. By pressing buttons in the application
  2. By pressing keyboard buttons

Both methods call the same function with the same parameters, but an error occurs when using the keyboard:enter image description here

Both calls the Enter () function

void FrameApp::Enter(const char* value)
{
    if (value == "1")
    {
        BUFER.append("1");
        CalcEditUpdate(BUFER);
    }
    else if (value == "2")
    {
        BUFER.append("2");
        CalcEditUpdate(BUFER);
    }
    else if (value == "3")
    {
        BUFER.append("3");
        CalcEditUpdate(BUFER);
    }
    else if (value == "4")
    {
        BUFER.append("4");
        CalcEditUpdate(BUFER);
    }
    else if (value == "5")
    {
        BUFER.append("5");
        CalcEditUpdate(BUFER);
    }
    else if (value == "6")
    {
        BUFER.append("6");
        CalcEditUpdate(BUFER);
    }
    else if (value == "7")
    {
        BUFER.append("7");
        CalcEditUpdate(BUFER);
    }
    else if (value == "8")
    {
        BUFER.append("8");
        CalcEditUpdate(BUFER);
    }
    else if (value == "9")
    {
        BUFER.append("9");
        CalcEditUpdate(BUFER);
    }
    else if (value == "0")
    {
        BUFER.append("0");
        CalcEditUpdate(BUFER);
    }
    else if (value == ",")
    {
        BUFER.append(",");
        CalcEditUpdate(BUFER);
    }
}

And depending on the pressed key, it updates the variable storing text for output. And updates the text field using the function:

void FrameApp::CalcEditUpdate(std::string bufer)
{
    calcEdit->SetValue(bufer);
}

All code:

#include "../inc/FrameApp.h"
 
FrameApp::FrameApp(const wxString& title, const wxPoint& pos, const wxSize & size) : wxFrame((wxFrame*)NULL, -1, title, pos, size)
{
    wxBoxSizer* mainSizer = new wxBoxSizer(wxVERTICAL);
 
    calcEdit = new wxTextCtrl(this, wxID_ANY, wxEmptyString, wxDefaultPosition, wxSize(-1, 60), wxTE_READONLY | wxTE_RIGHT | wxBORDER_RAISED);
    calcEdit->SetFont(wxFont(25, wxFONTFAMILY_ROMAN, wxFONTSTYLE_NORMAL, wxFONTWEIGHT_NORMAL, false, wxT("Bodoni MT")));
    mainSizer->Add(calcEdit, 0, wxEXPAND);
 
    wxStaticLine* calcEditBorder = new wxStaticLine(this, wxID_ANY, wxDefaultPosition, wxDefaultSize, wxLI_HORIZONTAL);
    mainSizer->Add(calcEditBorder, 0, wxEXPAND | wxBOTTOM, 5);
 
    wxBoxSizer* row1Sizer = new wxBoxSizer(wxHORIZONTAL);
    wxButton* btn7 = new wxButton((wxWindow*)this, wxID_ANY, wxT("7"), wxDefaultPosition, wxDefaultSize, 0);
    btn7->Connect(wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler(FrameApp::btnOnClick), NULL, this);
    row1Sizer->Add(btn7, 1, wxALL | wxEXPAND, 2);
    wxButton* btn8 = new wxButton((wxWindow*)this, wxID_ANY, wxT("8"), wxDefaultPosition, wxDefaultSize, 0);
    btn8->Connect(wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler(FrameApp::btnOnClick), NULL, this);
    row1Sizer->Add(btn8, 1, wxALL | wxEXPAND, 2);
    wxButton* btn9 = new wxButton((wxWindow*)this, wxID_ANY, wxT("9"), wxDefaultPosition, wxDefaultSize, 0);
    btn9->Connect(wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler(FrameApp::btnOnClick), NULL, this);
    row1Sizer->Add(btn9, 1, wxALL | wxEXPAND, 2);
    mainSizer->Add(row1Sizer, 1, wxALL | wxEXPAND, 2);
    
 
    wxBoxSizer* row2Sizer = new wxBoxSizer(wxHORIZONTAL);
    wxButton* btn4 = new wxButton((wxWindow*)this, wxID_ANY, wxT("4"), wxDefaultPosition, wxDefaultSize, 0);
    btn4->Connect(wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler(FrameApp::btnOnClick), NULL, this);
    row2Sizer->Add(btn4, 1, wxALL | wxEXPAND, 2);
    wxButton* btn5 = new wxButton((wxWindow*)this, wxID_ANY, wxT("5"), wxDefaultPosition, wxDefaultSize, 0);
    btn5->Connect(wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler(FrameApp::btnOnClick), NULL, this);
    row2Sizer->Add(btn5, 1, wxALL | wxEXPAND, 2);
    wxButton* btn6 = new wxButton((wxWindow*)this, wxID_ANY, wxT("6"), wxDefaultPosition, wxDefaultSize, 0);
    btn6->Connect(wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler(FrameApp::btnOnClick), NULL, this);
    row2Sizer->Add(btn6, 1, wxALL | wxEXPAND, 2);
    mainSizer->Add(row2Sizer, 1, wxALL | wxEXPAND, 2);
 
    wxBoxSizer* row3Sizer = new wxBoxSizer(wxHORIZONTAL);
    wxButton* btn1 = new wxButton((wxWindow*)this, wxID_ANY, wxT("1"), wxDefaultPosition, wxDefaultSize, 0);
    btn1->Connect(wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler(FrameApp::btnOnClick), NULL, this);
    row3Sizer->Add(btn1, 1, wxALL | wxEXPAND, 2);
    wxButton* btn2 = new wxButton((wxWindow*)this, wxID_ANY, wxT("2"), wxDefaultPosition, wxDefaultSize, 0);
    btn2->Connect(wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler(FrameApp::btnOnClick), NULL, this);
    row3Sizer->Add(btn2, 1, wxALL | wxEXPAND, 2);
    wxButton* btn3 = new wxButton((wxWindow*)this, wxID_ANY, wxT("3"), wxDefaultPosition, wxDefaultSize, 0);
    btn3->Connect(wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler(FrameApp::btnOnClick), NULL, this);
    row3Sizer->Add(btn3, 1, wxALL | wxEXPAND, 2);
    mainSizer->Add(row3Sizer, 1, wxALL | wxEXPAND, 2);
 
    wxBoxSizer* row4Sizer = new wxBoxSizer(wxHORIZONTAL);
    wxButton* btnPM = new wxButton((wxWindow*)this, wxID_ANY, wxT("+/-"), wxDefaultPosition, wxDefaultSize, 0);
    btnPM->Connect(wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler(FrameApp::btnOnClick), NULL, this);
    row4Sizer->Add(btnPM, 1, wxALL | wxEXPAND, 2);
    wxButton* btn0 = new wxButton((wxWindow*)this, wxID_ANY, wxT("0"), wxDefaultPosition, wxDefaultSize, 0);
    btn0->Connect(wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler(FrameApp::btnOnClick), NULL, this);
    row4Sizer->Add(btn0, 1, wxALL | wxEXPAND, 2);
    wxButton* btnD = new wxButton((wxWindow*)this, wxID_ANY, wxT(","), wxDefaultPosition, wxDefaultSize, 0);
    btnD->Connect(wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler(FrameApp::btnOnClick), NULL, this);
    row4Sizer->Add(btnD, 1, wxALL | wxEXPAND, 2);
    mainSizer->Add(row4Sizer, 1, wxALL | wxEXPAND, 2);
 
    SetSizer(mainSizer);
}
 
void FrameApp::btnOnClick(wxCommandEvent& event)
{
    wxButton* btn = (wxButton*)event.GetEventObject();
 
    if (btn->GetLabel() == "1")
    {
        Enter("1");
    }
    else if (btn->GetLabel() == "2")
    {
        Enter("2");
    }
    else if (btn->GetLabel() == "3")
    {
        Enter("3");
    }
    else if (btn->GetLabel() == "4")
    {
        Enter("4");
    }
    else if (btn->GetLabel() == "5")
    {
        Enter("5");
    }
    else if (btn->GetLabel() == "6")
    {
        Enter("6");
    }
    else if (btn->GetLabel() == "7")
    {
        Enter("7");
    }
    else if (btn->GetLabel() == "8")
    {
        Enter("8");
    }
    else if (btn->GetLabel() == "9")
    {
        Enter("9");
    }
    else if (btn->GetLabel() == "0")
    {
        Enter("0");
    }
    else if (btn->GetLabel() == ",")
    {
        Enter(",");
    }
}
 
void FrameApp::OnKeyDown(wxKeyEvent& event)
{
    switch ( event.GetKeyCode() )
    {
    case WXK_NUMPAD1:
        Enter("1");
        break;
    case WXK_NUMPAD2:
        Enter("2");
        break;
    case WXK_NUMPAD3:
        Enter("3");
        break;
    case WXK_NUMPAD4:
        Enter("4");
        break;
    case WXK_NUMPAD5:
        Enter("5");
        break;
    case WXK_NUMPAD6:
        Enter("6");
        break;
    case WXK_NUMPAD7:
        Enter("7");
        break;
    case WXK_NUMPAD8:
        Enter("8");
        break;
    case WXK_NUMPAD9:
        Enter("9");
        break;
    case WXK_NUMPAD0:
        Enter("0");
        break;
    case WXK_NUMPAD_SEPARATOR:
        Enter(",");
        break;
    }
}
 
void FrameApp::Enter(const char* value)
{
    if (value == "1")
    {
        BUFER.append("1");
        CalcEditUpdate(BUFER);
    }
    else if (value == "2")
    {
        BUFER.append("2");
        CalcEditUpdate(BUFER);
    }
    else if (value == "3")
    {
        BUFER.append("3");
        CalcEditUpdate(BUFER);
    }
    else if (value == "4")
    {
        BUFER.append("4");
        CalcEditUpdate(BUFER);
    }
    else if (value == "5")
    {
        BUFER.append("5");
        CalcEditUpdate(BUFER);
    }
    else if (value == "6")
    {
        BUFER.append("6");
        CalcEditUpdate(BUFER);
    }
    else if (value == "7")
    {
        BUFER.append("7");
        CalcEditUpdate(BUFER);
    }
    else if (value == "8")
    {
        BUFER.append("8");
        CalcEditUpdate(BUFER);
    }
    else if (value == "9")
    {
        BUFER.append("9");
        CalcEditUpdate(BUFER);
    }
    else if (value == "0")
    {
        BUFER.append("0");
        CalcEditUpdate(BUFER);
    }
    else if (value == ",")
    {
        BUFER.append(",");
        CalcEditUpdate(BUFER);
    }
}
 
void FrameApp::CalcEditUpdate(std::string bufer)
{
    calcEdit->SetValue(bufer);
}

What can cause this behavior when calling through the keyboard? The error itself appears on a call to the CalcEditUpdate () function.

In constructor of FrameApp i bind a btnOnClick() like this:

btn7->Connect(wxEVT_COMMAND_BUTTON_CLICKED, wxCommandEventHandler(FrameApp::btnOnClick), NULL, this);

In main.cpp i connect a handlers of onKeyDown() to App:

#include "main.h"

wxIMPLEMENT_APP(App);

bool App::OnInit()
{
    FrameApp* frame = new FrameApp(wxT("Calc"), wxDefaultPosition, wxSize(400, 550));
    frame->SetSizeHints(wxSize(400, 550), wxSize(400, 550));
    frame->Show(true);

    this->Connect(wxEVT_KEY_DOWN, wxKeyEventHandler(FrameApp::OnKeyDown));
    return true;
}

Headers with all others code of app

FrameApp.h

#pragma once
#include <wx/wxprec.h>
#ifndef WX_PRECOMP
#include <wx/wx.h>
#endif

#include <wx/statline.h>
#include <string>
#include <vector>

class FrameApp : public wxFrame
{
public:
    string BUFER;

    wxTextCtrl* calcEdit;

    FrameApp(const wxString& title, const wxPoint& pos, const wxSize& size);
    void btnOnClick(wxCommandEvent& event);
    void OnKeyDown(wxKeyEvent& event);
    void Enter(const char* value);
    void FrameApp::CalcEditUpdate(std::string bufer)
};

main.h

#pragma once
#include <wx/wxprec.h>
#ifndef WX_PRECOMP
#include <wx/wx.h>
#endif

#include "inc/FrameApp.h"

class App : public wxApp
{
public:
    bool OnInit();
};
Solution

  • You can easily see the difference between your 2 Connect() calls: you specify the object to call the method on correctly for btnOnClick, but not for OnKeyDown, so you end up calling the latter, which is a member of (incredibly confusingly named) FrameApp (which is not any kind of App at all) on your App object.

    You can, of course, just fix the problem by providing the correct parameters to the Connect() call but the right thing to do is not use this deprecated since 10+ years function and use Bind(), which would catch errors like this at compile-time, e.g.

    frame->Bind(wxEVT_KEY_DOWN, &FrameApp::OnKeyDown, frame);