Creating a simple tree view using Common Controls in C

Question

So I was trying to create a simple tree view using the Win32 API and CommnoControls. I've created a simple window, and in its WM_CREATE event, I've done the following:

HWND treeView = CreateWindowA(WC_TREEVIEWA, NULL, WS_VISIBLE | WS_CHILD, 10, 10,
        200, 500, window->info, (HMENU)1, GetModuleHandleA(NULL), NULL);

TVITEMA item = {0};
item.pszText = "My Item";

TVINSERTSTRUCTA insertStruct = {0};
insertStruct.hParent = NULL;
insertStruct.hInsertAfter = TVI_LAST;
insertStruct.item = item;
SendMessageA(treeView, TVM_INSERTITEMA, 0, &insertStruct);

The tree view does appear on the window, however the item (My Item) doesn't appear in it.

Is there anything else I need to do in order for it to appear? Maybe initialize something else? I tried to look in CommonControl's documentation but I didn't find anything else that would make sence to use... What am I doing wrong here?

Answer 1

Windows does not know that you provided text for the item because you failed to include TVIF_TEXT in the items mask member:

HWND treeView = CreateWindowA(WC_TREEVIEWA, NULL, WS_VISIBLE | WS_CHILD | TVS_HASBUTTONS | TVS_HASLINES | TVS_LINESATROOT, 10, 10,
        200, 500, window->info, (HMENU)1, GetModuleHandleA(NULL), NULL);


HTREEITEM hItem;
TVINSERTSTRUCTA insertStruct = {0};
TVITEMA*pItem = &insertStruct.item;
insertStruct.hParent = NULL;
insertStruct.hInsertAfter = TVI_ROOT;

pItem->mask = TVIF_TEXT;
pItem->pszText = "My Item";
hItem = (HTREEITEM) SendMessageA(treeView, TVM_INSERTITEMA, 0, (LPARAM) &insertStruct);

if (hItem)
{
    insertStruct.hParent = hItem;
    pItem->pszText = "A Child";
    hItem = (HTREEITEM) SendMessageA(treeView, TVM_INSERTITEMA, 0, (LPARAM) &insertStruct);
    if (hItem) SendMessage(treeView, TVM_ENSUREVISIBLE, 0, (LPARAM) hItem);
}

Use the line and button TVS_* styles to control how items are displayed.