+TFileItem is a utility class used to represent a file or directory. +It contains BasePath with the path to the directory where the item is located +on the local file system, and FileInfo with the TSearchRec values for the item. +
++TFileItem is the type used to represent the items passed as arguments to a +TFileItemCompareEvent handler routine. TFileItem instances are created and +used in the implementation of file listing and sort routines as well. +
++isFolder is a Boolean member which indicates if the item +represents a folder or directory on the local file system. Its value is +assigned in the Create constructor, and is set to True if the TSearchRec +instance in the DirInfo argument includes faDirectory in its Attr member. +
++Create stores values in the DirInfo and ABasePath arguments to the +FileInfo and BasePath properties in the class instance. isFolder is updated to +indicate whether the file item is a directory on the local file system. +
++BasePath is assigned in the Create constructor using the value +passed in the ABasePath argument. +
++FileInfo is assigned in the Create constructor using the value +passed in the DirInfo argument. +
++TFileItemCompareEvent is the type used to implement the +OnSortCompare event handler in TCustomShellTreeView. TFileItemCompareEvent +compares the file items specified in the Item1 and Item2 arguments to +determine which value occurs first in the sort order. +
++The return value is an Integer with the relative sort order for the +compared values: +
++An application can implement and assign a routine using the signature to the +OnSortCompare event handler in TCustomShellTreeView. Set its FileSortType +property to fstCustom to enable the handler routine. +
++The following is an item compare function, as implemented by forum member +d7_2_laz, used to order items with leading Underscore characters: +
+
+function TForm1.SortCompareUnderscore(Item1, Item2: TFileItem): integer;
+begin
+ // Make sure that folders are moved to the top
+ Result := ord(Item2.isFolder) - ord(Item1.isFolder);
+ if Result = 0 then
+ if (pos('_', Item1.FileInfo.Name) = 1) or
+ (pos('_', Item2.FileInfo.Name) = 1) then
+ Result := AnsiCompareText(Item1.FileInfo.Name, Item2.FileInfo.Name)
+ else
+ Result := CompareText(Item1.FileInfo.Name, Item2.FileInfo.Name);
+end;
+
++Sort File Items by Date +
+
+function TForm1.SortCompareByDate(Item1, Item2: TFileItem): integer;
+begin
+ // Folders first ...
+ Result := ord(Item2.isFolder) - ord(Item1.isFolder);
+ if Result = 0 then
+ begin
+ // then file date ...
+ Result := CompareValue(Item1.FileInfo.TimeStamp, Item2.FileInfo.TimeStamp);
+ if Result = 0 then
+ // then file name
+ Result := CompareText(Item1.FileInfo.Name, Item2.FileInfo.Name);
+ end;
+end;
+
++Sort File Items by Size +
+
+function TForm1.SortCompareBySize(Item1, Item2: TFileItem): integer;
+begin
+ // Folders first
+ Result := ord(Item2.isFolder) - ord(Item1.isFolder);
+ if Result = 0 then
+ begin
+ // then file size ...
+ Result := Item1.FileInfo.Size - Item2.FileInfo.Size;
+ if Result = 0 then
+ // then file name
+ Result := CompareText(Item1.FileInfo.Name, Item2.FileInfo.Name);
+ end;
+end;
+
++OnSortCompare is a TFileItemCompareEvent property with +the event handler signalled to implement a custom file sort for the tree view +control. OnSortCompare is used to order the directories or files displayed in +the tree view control when its FileSortType property is set to fstCustom. +
++Changing the routine assigned to the property causes the Items in the control +to be reloaded and ordered using the new file sort compare routine. +
++An application can implement and assign a routine using the signature perform +custom file comparison routines using various attributes. The following is an +item compare function, as implemented by forum member d7_2_laz, used to order +items with leading Underscore characters: +
+
+function TForm1.SortCompareUnderscore(Item1, Item2: TFileItem): integer;
+begin
+ // Make sure that folders are moved to the top
+ Result := ord(Item2.isFolder) - ord(Item1.isFolder);
+ if Result = 0 then
+ if (pos('_', Item1.FileInfo.Name) = 1) or
+ (pos('_', Item2.FileInfo.Name) = 1) then
+ Result := AnsiCompareText(Item1.FileInfo.Name, Item2.FileInfo.Name)
+ else
+ Result := CompareText(Item1.FileInfo.Name, Item2.FileInfo.Name);
+end;
+
++Sort File Items by Date +
+
+function TForm1.SortCompareByDate(Item1, Item2: TFileItem): integer;
+begin
+ // Folders first ...
+ Result := ord(Item2.isFolder) - ord(Item1.isFolder);
+ if Result = 0 then
+ begin
+ // then file date ...
+ Result := CompareValue(Item1.FileInfo.TimeStamp, Item2.FileInfo.TimeStamp);
+ if Result = 0 then
+ // then file name
+ Result := CompareText(Item1.FileInfo.Name, Item2.FileInfo.Name);
+ end;
+end;
+
++Sort File Items by Size +
+
+function TForm1.SortCompareBySize(Item1, Item2: TFileItem): integer;
+begin
+ // Folders first
+ Result := ord(Item2.isFolder) - ord(Item1.isFolder);
+ if Result = 0 then
+ begin
+ // then file size ...
+ Result := Item1.FileInfo.Size - Item2.FileInfo.Size;
+ if Result = 0 then
+ // then file name
+ Result := CompareText(Item1.FileInfo.Name, Item2.FileInfo.Name);
+ end;
+end;
+
+