How to add file drag and drop support to a wxWidgets application

main.cpp

#include "main.hpp"

#include "wx/dnd.h"
#include "wx/filename.h"

#define APP_NAME wxString("Drag 'n' Drop Example")

class MyApp: public wxApp
{
	virtual bool OnInit();
};

enum
{
	ID_Quit = 1,
	ID_FileOpen,
	ID_About,
};


BEGIN_EVENT_TABLE(MyFrame, wxFrame)
	EVT_MENU(ID_Quit, MyFrame::OnQuit)
	EVT_MENU(ID_FileOpen, MyFrame::OnOpen)
	EVT_MENU(ID_About, MyFrame::OnAbout)
END_EVENT_TABLE()

IMPLEMENT_APP(MyApp)


bool MyApp::OnInit()
{
	wxInitAllImageHandlers();

	MyFrame *frame = new MyFrame(APP_NAME, wxPoint(50,50), wxSize(450,340));
	frame->Show(TRUE);
	SetTopWindow(frame);
	return TRUE;
}

class MyDropTarget : public wxFileDropTarget
{
public:
	MyDropTarget::MyDropTarget(MyFrame* parent)
		: wxFileDropTarget()
	{
		mParent = parent;
	}

	bool MyDropTarget::OnDropFiles(wxCoord x, wxCoord y, const wxArrayString& filenames)
	{
		mParent->OpenFile(filenames[0]); // Just open the first file if several are dropped onto the window
		return true;
	}

private:
	MyFrame* mParent;
};

MyFrame::MyFrame(const wxString& title, const wxPoint& pos, const wxSize& size)
: wxFrame((wxFrame *)NULL, -1, title, pos, size)
{
	SetMinSize(size);

	wxMenu* menuHelp = new wxMenu;
	menuHelp->Append( ID_About, "&About..." );

	wxMenu *menuFile = new wxMenu;
	menuFile->Append(ID_FileOpen, "&Open");
	menuFile->AppendSeparator();
	menuFile->Append( ID_Quit, "E&xit" );

	wxMenuBar *menuBar = new wxMenuBar;
	menuBar->Append(menuFile, "&File" );
	menuBar->Append(menuHelp, "&Help");

	SetMenuBar(menuBar);

	mDropper = new MyDropTarget(this);
	SetDropTarget(mDropper);
}

MyFrame::~MyFrame()
{
}

void MyFrame::OnQuit(wxCommandEvent& WXUNUSED(event))
{
	Close(TRUE);
}

void MyFrame::OnAbout(wxCommandEvent& WXUNUSED(event))
{
	wxMessageBox("Copyright (c) 2013 Mike Jones\naudioprogrammermike@gmail.com", APP_NAME, wxOK | wxICON_INFORMATION, this);
}

void MyFrame::OnOpen(wxCommandEvent& event)
{
	wxFileDialog* OpenDialog = new wxFileDialog(
		this, _("Choose a file to open"), wxEmptyString, wxEmptyString, 
		_("All Files (*.*)|*.*"),
		wxFD_OPEN, wxDefaultPosition);

	if (OpenDialog->ShowModal() == wxID_OK) // if the user click "Open" instead of "Cancel"
	{
		wxString CurrentDocPath = OpenDialog->GetPath();
		OpenFile(CurrentDocPath);
	}

	// Clean up after ourselves
	OpenDialog->Destroy();
}

void MyFrame::OpenFile(wxString path)
{
	wxFileName filename(path);
	SetTitle(APP_NAME << " - " << filename.GetFullName()); // Set the Title to reflect the file open
}

main.hpp

#ifndef _MAIN_HPP_
#define _MAIN_HPP_

#include "wx/config.h"
#include "wx/wx.h"

class MyDropTarget;

class MyFrame: public wxFrame
{
public:
	MyFrame(const wxString& title, 
		const wxPoint& pos, const wxSize& size);

	virtual ~MyFrame();

	void OnQuit(wxCommandEvent& event);
	void OnAbout(wxCommandEvent& event);
	void OnOpen(wxCommandEvent& event);

	void OpenFile(wxString filename);

private:
	MyDropTarget* mDropper;
	DECLARE_EVENT_TABLE()
};

#endif //_MAIN_HPP_