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Brad's VB-32 Programs & Samples |
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| Posted: 10/28/99, last update: 10/28/99 | ||
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Brad's VB-32 Programs & Samples |
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| Posted: 10/28/99, last update: 10/28/99 | ||
| VB TreeView and ListView
Explorer demo Well, I guess this demo has been due out for a while... It's basically the EnumDeskVB demo stripped of much of its complicated (and excessive) code that is not only required to create and operate the real treeview and listview common controls, but also the code used for the complicated IShellFolder reference handling as well. The demo is honed into the tightest and most compact possible and emulates almost complete Explorer treeview and listview window functionality, but using VB controls. Though it does less than EnumDeskVB, and with less than one half of the code, it actually does a lot more, and does it better... As with EnumDeskVB, this demo utilizes both the IShellFolder interface, and the IShellFolder's child interface, the IEnumIDList interface, while processing the notification messages sent by the TreeView and ListView controls; it also enumerates the shell's namespace and displays the names and icons of any and all file system objects in each control. Other interesting Explorer-like behavior is thrown in, including right-click shell context menu functionality with help from the IContextMenu interface, and for good measure, a deceivingly simple little splitter bar is used to simultaneously adjust the size of both control windows within their parent Form. Other various (and subtle) Explorer view functionality is also demonstrated. But unlike EnumDeskVB, this demo does a few other things as well. First, notification messages sent by the TreeView and ListView controls are received directly within the controls' subclassing window procedures via the OCM_NOTIFY message, eliminating the need to subclass the controls' parent window, typically a Form. The system imagelist is assigned directly to both the TreeView and ListView controls, as is demonstrated in both the VB Directory TreeView and System Imagelist demos, respectively. Directional sort icons are also displayed in ListView column headers as is demonstrated by the ListView Header Sort Icons demo. But where things really begin to get interesting is the demo's use of the IShellDetails interface, which provides ListView column information for the contents of most shell folders, without the need to explicitly extract the details with the FindFirst/NextFile APIs. Also, item details are sorted in the respective ListView columns by passing the column's index value to the IShellFolder CompareIDs member function, functionality that was just recently discovered in this part of the universe. As always, the source code is fairly adequately documented, and has been tested and run successfully without incident using controls from both Comctl32.ocx and Mscomctl.ocx in VB5 and VB6 on Win95/IE3, Win98, WinNT4 SP3 and SP5, and Win2K rc2. Note that the Mscomctl.ocx ListView exhibits unusual behavior when ListItems are selected in large icon view. This may be due to directly setting ListItem icon indices with the listview's LVM_SETITEM message, but the exact cause has yet to be determined... Download vbexplorer.zip (65kb) |