Treeview Control Demo

To create a TreeView control specify WC_TREEVIEW as the window class and register the class by specifying the ICC_TREEVIEW_CLASSES bit flag in the accompanying INITCOMMONCONTROLSEX structure.

#define _WIN32_WINNT 0x0501
#include <windows.h>
#include <commctrl.h>

#pragma comment(lib,"comctl32.lib")

#define ID_TREEVIEW     1
#define ID_CREATEBUTTON 2
#define ID_DELETEBUTTON 3
#define ID_EDITBOX      4

HWND hwndEdit;
HWND hwndTV;

LRESULT CALLBACK WndProc(HWND,UINT,WPARAM,LPARAM);
void CreateControls(HWND);
void addnode();

int WINAPI WinMain(HINSTANCE hInstance,
                   HINSTANCE hPrevInstance,
                   LPSTR lpCmdLine,
                   int nCmdShow)
{
    HWND hwnd;
    MSG msg;
    WNDCLASS wc;
    wc.style=CS_HREDRAW | CS_VREDRAW;
    wc.lpfnWndProc=WndProc;
    wc.cbClsExtra=0;
    wc.cbWndExtra=0;
    wc.hInstance=hInstance;
    wc.hIcon=LoadIcon(NULL,IDI_APPLICATION);
    wc.hCursor=LoadCursor(NULL,IDC_ARROW);
    wc.hbrBackground=(HBRUSH)(COLOR_WINDOW+1);
    wc.lpszMenuName=NULL;
    wc.lpszClassName=TEXT("myWindowClass");
    RegisterClass(&wc);

    hwnd=CreateWindow(
        TEXT("myWindowClass"),
        TEXT("Treeview Control"),
        WS_OVERLAPPEDWINDOW | WS_VISIBLE,
        10,
        10,
        550,
        250,
        NULL,
        NULL,
        hInstance,
        NULL);

    while(GetMessage(&msg,NULL,0,0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hwnd,
                         UINT msg,
                         WPARAM wParam,
                         LPARAM lParam)
{
switch(msg)
{
case WM_CREATE:
    CreateControls(hwnd);
    addnode();
break;
case WM_COMMAND:
if(HIWORD(wParam)==BN_CLICKED)
{
switch(LOWORD(wParam))
{
case ID_CREATEBUTTON:
    addnode();
break;

case ID_DELETEBUTTON:
{
    HTREEITEM item;
    item=TreeView_GetSelection(hwndTV);
    if(item)
    {
        TreeView_DeleteItem(hwndTV,item);
        SetFocus(hwndTV);
    }
}
break;
}
}
break;

case WM_NOTIFY:
{
    LPNMHDR hdr;
    hdr=(LPNMHDR)lParam;
    if(hdr->code==NM_DBLCLK)
    {
        MessageBox(hwnd,
        TEXT("Tree item double clicked"),
        TEXT("Tree View"),
        MB_OK);
    }

    if(hdr->code==TVN_SELCHANGED)
    {
        // selection changed
    }
}
break;

case WM_DESTROY:
    PostQuitMessage(0);
break;

default:
return DefWindowProc(hwnd,msg,wParam,lParam);
}
return 0;
}

void CreateControls(HWND hwnd)
{
INITCOMMONCONTROLSEX icex;
icex.dwSize=sizeof(INITCOMMONCONTROLSEX);
icex.dwICC=ICC_TREEVIEW_CLASSES;
InitCommonControlsEx(&icex);

hwndTV=CreateWindowEx(
0,
WC_TREEVIEW,
TEXT(""),
WS_CHILD |
WS_VISIBLE |
WS_BORDER |
TVS_HASLINES |
TVS_LINESATROOT |
TVS_HASBUTTONS |
TVS_SHOWSELALWAYS,
10,
10,
250,
150,
hwnd,
(HMENU)ID_TREEVIEW,
GetModuleHandle(NULL),
NULL);

hwndEdit=CreateWindow(
TEXT("edit"),
NULL,
WS_CHILD |
WS_VISIBLE |
WS_BORDER,
290,
170,
120,
25,
hwnd,
(HMENU)ID_EDITBOX,
GetModuleHandle(NULL),
NULL);

CreateWindow(
TEXT("button"),
TEXT("Add Child"),
WS_CHILD |
WS_VISIBLE,
20,
170,
120,
25,
hwnd,
(HMENU)ID_CREATEBUTTON,
GetModuleHandle(NULL),
NULL);

CreateWindow(
TEXT("button"),
TEXT("Delete Selected"),
WS_CHILD |
WS_VISIBLE,
150,
170,
120,
25,
hwnd,
(HMENU)ID_DELETEBUTTON,
GetModuleHandle(NULL),
NULL);
}

void addnode()
{
TV_INSERTSTRUCT tvinsert;
HTREEITEM selected;
ZeroMemory(&tvinsert,sizeof(TV_INSERTSTRUCT));
tvinsert.hInsertAfter=TVI_LAST;
tvinsert.item.mask=TVIF_TEXT;
// first node
if(TreeView_GetCount(hwndTV)==0)
{
    tvinsert.hParent=TVI_ROOT;
    tvinsert.item.pszText=TEXT("Root");
}
// child nodes
else
{
TCHAR text[100];
GetWindowText(hwndEdit,text,100);
if(lstrlen(text)==0)
{
    return;
}

selected=TreeView_GetSelection(hwndTV);

if(selected==NULL)
{
    selected=TVI_ROOT;
}
tvinsert.hParent=selected;
tvinsert.item.pszText=text;
}

TreeView_InsertItem(hwndTV,&tvinsert);
SetFocus(hwndTV);
}