# TShellListView

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Note: This documentation is not intended to be thorough, but it is enough to get a beginner started on the use of the object. This particular discussion is biased to MS-Windows, and particularly Windows 7. At any-rate, its functionality appears to be OS-Specific, and care must be taken when porting code using this object to another OS. The default behavior appears to be to list only filenames. While the behavior can be made to be Explorer-like, icons do not appear by default.

TShellListView displays files according to its Root property. The Root property contains the whole path from the drive letter to the current directory. If using it to show the complete path including a selected file, then you need to append a slash ('\' or '/' in UNIX) to Root, as in:

 pathname := '"' + svList.Root + '\' + svList.Selected.Caption + '"'; 

where svList is the name of a TShellListView object, and svList.Selected.Caption contains the name of a file selected by the user. pathname is a string variable containing the entire path from the drive letter to the file name and extension. The double quotes are recommended to be applied in MS-Windows if the path contains spaces. This makes the usual process of escaping spaces in filenames with %20 unnecessary in Windows.

### Talking to TShellTreeView

There is little coding to do in getting TShellListView to communicate with TShellTreeView. In the Object Inspector, under the Events tab, for TShellTreeView, set the event "ShellListView" to the name of your TShellListView object. This ought to be already stored on a dropdown menu if both TShellListView and TShellTreeView objects are deployed on your form. For completeness, so that both objects respond to each other, set the ShellTreeView event of TShellListView to the name of your TShellTreeView object.

Alternatively, if we let svList be the TShellListView object; and svTree be the TShellTreeView object, then these properties can be set programmatically:

 

 svList.ShellTreeView := svTree; svTree.ShellListView := svList; 

The result is to invoke Explorer-like behavior in their responsiveness.

### Opening documents

In Windows, the generic command for opening a file in TShellListView is OpenDocument(pathname), where pathname is the path to the file. For this you should remember to add lclintf to your uses clause. Other operating systems can get away with using OpenURL(pathname), except that spaces must be escaped with a %20 string, and file:// must prepend the pathname. Example:  

 OpenURL('file:///home/joe/text/foo%20bar.txt'); 

Contrast this with the Windows convention:

 

 OpenDocument("C:\Users\Joe\My Documents\xyz.txt"); 

OpenURL is not recommended for use in Windows for opening documents using the file:// URI scheme.

Because OpenDocument also acts as a Boolean function, it returns false if there is no way in the registry to open the file. If we let pathname be the full path to the file from the drive letter to the filename, this statement will open the document if OpenDocument(pathname) returns True:

 

 if not OpenDocument(pathname) then // no method to display this file type ShowMessage('Cannot display ' + pathname); 

### Dealing with strangeness

When running a program with this object, you may notice that double-clicking on a filename will allow you to edit it or delete its name entirely by default. These sorts of changes appear to have no effect on the file itself. To stop this behavior, set the ReadOnly property to True.