Populate a TTreeView With Directory Tree And Filtering

Question

On a Lazarus 0.9.28.2 project I have a TTreeView, with the name DirTree on my Form(frmConvert), but I want to populate it with all the directory tree, since C:\.

Like this:

And when the user select the directory, in the second TTreeView, with the name FileTree, appear all the files in that directory, but filtered to show only PDFs.

Also I want help to put these icons, because is very nice to be more organized and friendly for the end-user.

Questions

• How can I populate the first TTreeView(DirTree) with all the directorys, like in the image?
• How can I populate the second TTreeview(FileTree) with the files on the directory selected on DirTree?
• How can I set a icon for each folder(only folders) on DirTree?

Answer 1

Code to populate the dirTree (REVISED)

procedure TForm1.FormClick(Sender: TObject);
var
  sr: TSearchRec;
  FileAttrs: Integer;
  theRootNode : tTreeNode;
  theNode : tTreeNode;
begin
   FileAttrs := faDirectory;     // Only care about directories
   theRootNode := DirTree.Items.AddFirst(nil,'c:\');
   if FindFirst('c:\*.*', FileAttrs, sr) = 0 then
    begin
      repeat
        if (sr.Attr and FileAttrs) = sr.Attr then
        begin
            theNode := dirTree.Items.AddChild(theRootNode,sr.name);
            AddDirectories(theNode,'c:\'+sr.Name);
        end;
      until FindNext(sr) <> 0;
      FindClose(sr);
    end;
//    DirTree.FullExpand;
end;

*Code to populate FileTree (REVISED) *

procedure TForm1.FilteredTV(theDir: string;ext:String;startNode:tTreeNode);
var
  sr: TSearchRec;
  FileAttrs: Integer;
  theNode : tTreeNode;
begin
   if copy(ext,1,1)<>'.' then ext := '.'+ext;
   FileAttrs := faAnyfile;
   if startNode = nil then
       StartNode := FileTree.Items.AddFirst(nil,theDir);
   if FindFirst(theDir+'\*.*', FileAttrs, sr) = 0 then
    begin
      repeat
        if (sr.Attr=faDirectory) and (copy(sr.Name,1,1)<>'.') then
            begin
                theNode := FileTree.Items.AddChild(StartNode,sr.name);
                theNode.ImageIndex := 0;   // Use folder image for directories
                FilteredTV(theDir+'\'+sr.name,ext,theNode);
            end
        else
            if ((sr.Attr and FileAttrs) = sr.Attr) and (ExtractFileExt(sr.name)=ext)
            then
            begin
                theNode := FileTree.Items.AddChild(StartNode,sr.name);
                theNode.ImageIndex := -1;   // No image for files
            end;

      until FindNext(sr) <> 0;
      FindClose(sr);
    end;
    FileTree.FullExpand;
end;

Additional procedure to add to form

procedure TForm1.AddDirectories(theNode: tTreeNode; cPath: string);
var
  sr: TSearchRec;
  FileAttrs: Integer;
  theNewNode : tTreeNode;
begin
   FileAttrs := faDirectory;     // Only care about directories
   if FindFirst(cPath+'\*.*', FileAttrs, sr) = 0 then
    begin
      repeat
        if  ((sr.Attr and FileAttrs) = sr.Attr) and (copy(sr.Name,1,1) <> '.')
        then
        begin
            theNewNode := dirTree.Items.AddChild(theNode,sr.name);
            AddDirectories(theNewNode,cPath+'\'+sr.Name);
        end;
      until FindNext(sr) <> 0;
      FindClose(sr);
    end;
end;

You need to add an image list to your form, add a folder icon to it (there is one in the borland common files) and then associated the image list with the directory treeview and the filetree treeview

EXAMPLE OF HOW TO CALLED FILTEREDTV procedure

Attach the following code to the OnClick event of the directory tree

procedure TForm1.DirTreeClick(Sender: TObject);
var
  cBuild : string;
  theNode : tTreeNode;
begin
    if DirTree.Selected <> nil then
    begin
        theNode := DirTree.Selected;
        cBuild := theNode.Text;
        while theNode.Parent <> nil do
        begin
            cBuild := theNode.Parent.Text+'\'+cBuild;
            theNode := theNode.Parent;
        end;
        cBuild := stringReplace(cBuild,'\\','\',[rfReplaceAll]);
        FilteredTV(cBuild,'pdf',nil);
    end;

end;