如何初始化图像列表
树形视图控件中的每个项目都可以有两个与之相关的图像。 一个项目被选中时会显示一个图像,未被选中时会显示另一个图像。 要在树形视图项目中包含图像,首先要使用 Image Lists 函数来创建图像列表并添加图像。 然后使用 TVM_SETIMAGELIST 消息将图像列表与树形视图控件关联起来。
需要了解的事项
技术
先决条件
- C/C++
- Windows 用户界面编程
说明
初始化图像列表
以下示例创建了一个图像列表,向列表中添加了三个位图,并将图像列表与树视图控件相关联。
// InitTreeViewImageLists - creates an image list, adds three bitmaps
// to it, and associates the image list with a tree-view control.
// Returns TRUE if successful, or FALSE otherwise.
// hwndTV - handle to the tree-view control.
//
// Global variables and constants:
// g_hInst - the global instance handle.
// g_nOpen, g_nClosed, and g_nDocument - global indexes of the images.
// CX_BITMAP and CY_BITMAP - width and height of an icon.
// NUM_BITMAPS - number of bitmaps to add to the image list.
// IDB_OPEN_FILE, IDB_CLOSED_FILE, IDB_DOCUMENT -
// resource identifiers of the bitmaps.
BOOL InitTreeViewImageLists(HWND hwndTV)
{
HIMAGELIST himl; // handle to image list
HBITMAP hbmp; // handle to bitmap
// Create the image list.
if ((himl = ImageList_Create(CX_BITMAP,
CY_BITMAP,
FALSE,
NUM_BITMAPS, 0)) == NULL)
return FALSE;
// Add the open file, closed file, and document bitmaps.
hbmp = LoadBitmap(g_hInst, MAKEINTRESOURCE(IDB_OPEN_FILE));
g_nOpen = ImageList_Add(himl, hbmp, (HBITMAP)NULL);
DeleteObject(hbmp);
hbmp = LoadBitmap(g_hInst, MAKEINTRESOURCE(IDB_CLOSED_FILE));
g_nClosed = ImageList_Add(himl, hbmp, (HBITMAP)NULL);
DeleteObject(hbmp);
hbmp = LoadBitmap(g_hInst, MAKEINTRESOURCE(IDB_DOCUMENT));
g_nDocument = ImageList_Add(himl, hbmp, (HBITMAP)NULL);
DeleteObject(hbmp);
// Fail if not all of the images were added.
if (ImageList_GetImageCount(himl) < 3)
return FALSE;
// Associate the image list with the tree-view control.
TreeView_SetImageList(hwndTV, himl, TVSIL_NORMAL);
return TRUE;
}
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