Advanced MFC Programming

Chapter 14. Views
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if(!ff.IsDirectory())
{
szFileName=ff.GetFilePath();
hIcon=GetIconFromFile(szFileName, SHGFI_LARGEICON);
if(hIcon != NULL)
{
pilNormal->Add(hIcon);
bUseDefaultNormalIcon=FALSE;
nNumImages++;
}
else
{
hIcon=GetIconFromFile(szFileName, SHGFI_SHELLICONSIZE);
if(hIcon != NULL)
{
pilNormal->Add(hIcon);
bUseDefaultNormalIcon=FALSE;
nNumImages++;
}
}
In rare cases, some files may have small embedded or registered icon but no corresponding big icon, or
vice versa. In any case, the embedded or registered icon has the highre priority to be used. The newly
obtained icon is added to the image list by calling function CImageList::Add(…).
14.8 Simple Explorer, Step 6: Clicking and Double Clicking
Sample 14.8\Exoplorer is based on sample 14.7\Explorer. In this sample, when the user clicks or
double clicks the left button on a directory node contained in the tree control, the current working directory
will be changed and the contents of the list view will also be updated.
If the double clicking expands a node, we need to pay attention to the newly revealed nodes: if any
directory contains sub-directories, we need to add new nodes so that the node button will be automatically
enabled.
Tree Control Messages
Mouse clicking events are sent through WM_NOTIFY messages. For tree control, various activities of tree
items can be handled by processing this message. In MFC, this message can be mapped to a member
function by using macro ON_NOTIFY_REFLECT. This macro has two parameters, the first specifies the event
type, the second specifies the member function name. There are many types of events, for example, mouse
button clicking event is defined as NM_CLICK, and the node expanding event is defined as
TVN_ITEMEXPANDING. Fortunately, in MFC, message mapping for these events can be easily implemented
through using Class Wizard. In sample 14.8\Explorer, we trap mouse clicking and node expanding events
to functions CDirView:: OnClick(…) and CDirView::OnItemExpanding(…) respectively.
Obtaining Full Path
When the user clicks mouse on a node, first we need to find out the path represented by that node.
Although the directory name is stored as the item text for each node, it is not a full path. We need a full
path in order to change the current working directory. In the sample, function CDirView::GetDir(…) is
implemented to obtain the full path represented by any item. Within this function, we keep on retrieving the
item’s parent node until root is reached, and combining the obtained directory names to form a full path.
Finding out the Clicked Item
After receiving NM_CLICK notification, we can call function CTreeCtrl::HitTest(…) to find out the
handle of the item that was clicked. We need to pass the current mouse position to this function. The
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