The following code demonstrates how to enumerate, add, and select ltmfConvert object target formats:
#include "ltmf.h"
#include "resource.h"
#include "tchar.h"
#include "stdio.h"
HINSTANCE g_hInstance; // application instance handle
IltmfConvert* g_pConvert; // convert object's interface pointer
//
// BuildTargetFormatList
// fills a listbox to match the contents of the collection
//
// pTargetFormats = format collection's interface pointer
// hwndListBox = listbox window handle
//
void BuildTargetFormatList(IltmfTargetFormats* pTargetFormats, HWND hwndListBox)
{
long i;
long count;
int selected = -1;
int listcount = 0;
// reset the listbox contents
SendMessage(hwndListBox, LB_RESETCONTENT, 0, 0);
// get the collection's item count
pTargetFormats->get_Count(&count);
for(i = 0; i < count; i++)
{
IltmfTargetFormat* pTargetFormat;
BSTR bstr;
TCHAR sz[256];
int index;
VARIANT_BOOL f;
// retrieve collection item
pTargetFormats->Item(i, &pTargetFormat);
// add only formats that are available
pTargetFormat->get_Available(&f);
if (f)
{
// get displayable name
pTargetFormat->get_Name(&bstr);
// convert from unicode
_stprintf(sz, _T("%ls"), bstr);
// free name
SysFreeString(bstr);
// add the name to the listbox
index = SendMessage(hwndListBox, LB_ADDSTRING, 0, (LPARAM)(LPCTSTR)sz);
// associate the listbox item with the collection item index
SendMessage(hwndListBox, LB_SETITEMDATA, index, i);
// remember this listbox item, if it is selected in the collection
pTargetFormat->get_Selected(&f);
if (f)
selected = i;
listcount++;
}
// free the collection item
pTargetFormat->Release();
}
// select the appropriate listbox item
for(i = 0; i < listcount; i++)
{
if(selected == (long) SendMessage(hwndListBox, LB_GETITEMDATA, i, 0))
{
SendMessage(hwndListBox, LB_SETCURSEL, i, 0);
break;
}
}
}
//
// TargetFormatSelectionChanged
// called to reflect changes in the listbox selection
//
// pTargetFormats = format collection's interface pointer
// hwndListBox = listbox window handle
//
void TargetFormatSelectionChanged(IltmfTargetFormats* pTargetFormats, HWND hwndListBox)
{
int index;
long item;
int i;
int count;
HRESULT hr;
// get the index of current listbox selection
index = (int) SendMessage(hwndListBox, LB_GETCURSEL, 0, 0);
if(index < 0)
{
// clear selection
pTargetFormats->put_Selection(-1);
}
else
{
// get the collection item index
item = (long) SendMessage(hwndListBox, LB_GETITEMDATA, index, 0);
// select the item
#ifdef _DEBUG
{
IltmfTargetFormat* pTargetFormat;
pTargetFormats->Item(item, &pTargetFormat);
hr = pTargetFormat->put_Selected(VARIANT_TRUE);
pTargetFormat->Release();
}
#else
hr = pTargetFormats->put_Selection(item);
#endif
// if new selection failed, we need to force the listbox to match the actual selection
if(FAILED(hr))
{
// get the real selection
pTargetFormats->get_Selection(&item);
// find the matching listbox item
count = (int) SendMessage(hwndListBox, LB_GETCOUNT, 0, 0);
for(i = 0; i < count; i++)
{
if(item == (long) SendMessage(hwndListBox, LB_GETITEMDATA, i, 0))
{
SendMessage(hwndListBox, LB_SETCURSEL, i, 0);
break;
}
}
}
}
}
//
// TargetFormatDlgProc
// selects object formats
//
BOOL CALLBACK TargetFormatDlgProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
IltmfTargetFormats* pTargetFormats;
switch (msg)
{
case WM_INITDIALOG:
// initialize the target format listbox
g_pConvert->get_TargetFormats(&pTargetFormats);
BuildTargetFormatList(pTargetFormats, GetDlgItem(hwnd, IDC_TARGETFORMATS));
pTargetFormats->Release();
return TRUE;
break;
case WM_COMMAND:
switch(LOWORD(wParam))
{
case IDC_TARGETFORMATS:
if(HIWORD(wParam) == LBN_SELCHANGE)
{
// select the target format
g_pConvert->get_TargetFormats(&pTargetFormats);
TargetFormatSelectionChanged(pTargetFormats, GetDlgItem(hwnd, IDC_TARGETFORMATS));
pTargetFormats->Release();
}
break;
case IDOK:
EndDialog(hwnd, IDOK);
return TRUE;
break;
}
break;
}
return FALSE;
}
int APIENTRY WinMain(HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nCmdShow)
{
HRESULT hr;
g_hInstance = hInstance;
// initialize COM library
hr = CoInitialize(NULL);
if(FAILED(hr))
goto error;
// create the convert object
hr = CoCreateInstance(CLSID_ltmfConvert, NULL, CLSCTX_INPROC_SERVER, IID_IltmfConvert, (void**) &g_pConvert);
if(FAILED(hr))
goto error;
DialogBox(g_hInstance, (LPCTSTR)IDD_TARGETFORMATDLG, NULL, TargetFormatDlgProc);
error:
// cleanup
if(g_pConvert)
g_pConvert->Release();
CoUninitialize();
return 0;
}