Use TreeView to display Directories : TreeView : GUI Windows Forms C# Examples

    
/*  Quote  from  

Programming  .NET  Windows  Applications

By  Jesse  Liberty,  Dan  Hurwitz
First  Edition  October  2003  
Pages:  1246  (More  details)
*/

using  System;
using  System.Drawing;
using  System.Windows.Forms;
using  System.IO;                //  necessary  for  Directory  info

public  class  TreeViewDirectories  :  Form
{
    TreeView  tvw;
    CheckBox  cb;
    Button  btnSelected;
    Button  btnExpand;
    Button  btnExpandAll;
    Button  btnCollapse;
    Button  btnCollapseAll;
    Button  btnToggle;

    public  TreeViewDirectories()
    {
        Size  =  new  Size(400,600);

        ImageList  imgList  =  new  ImageList();
        Image  img;

        String[]  arFiles  =  {"1.ico","2.ico","3.ico",".ico"};


        for  (int  i  =  0;  i  <  arFiles.Length;  i++)
        {
            img  =  Image.FromFile(arFiles[i]);
            imgList.Images.Add(img);
        }

        tvw  =  new  TreeView();
        tvw.Parent  =  this;
        tvw.Location  =  new  Point(10,10);
        tvw.Size  =  new  Size(ClientSize.Width  -  20,  Height  -  200);
        tvw.Anchor  =  AnchorStyles.Top  |  AnchorStyles.Left  |  
                    AnchorStyles.Right  |  AnchorStyles.Bottom;
        tvw.BackColor  =  Color.Moccasin;
        tvw.ForeColor  =  Color.DarkRed;
        tvw.BorderStyle  =  BorderStyle.Fixed3D;
        tvw.FullRowSelect  =  false;        
        tvw.ShowLines  =  true;            
        tvw.ShowPlusMinus  =  true;        
        tvw.Scrollable  =  true;            
        tvw.HideSelection  =  false;    
        tvw.HotTracking  =  true;    
        tvw.ImageList  =  imgList;
        tvw.ImageIndex  =  1;
        tvw.SelectedImageIndex  =  2;
        tvw.Indent  =  35;
        tvw.Font  =  new  Font("Times  New  Roman",  20f);
        tvw.ItemHeight  =  tvw.Font.Height  *  2;
        tvw.BeforeExpand  +=  new  TreeViewCancelEventHandler(tvw_BeforeExpand);

        cb  =  new  CheckBox();
        cb.Parent  =  this;
        cb.Location  =  new  Point((Width  -  cb.Width)  *  2  /  10,  tvw.Bottom  +  25);
        cb.Text  =  "Show  Files";
        cb.Anchor  =  AnchorStyles.Bottom;
        cb.CheckedChanged  +=  new  EventHandler(cb_CheckedChanged);

        btnSelected  =  new  Button();
        btnSelected.Parent  =  this;
        btnSelected.Text  =  "&SelectedNode";
        int  xSize  =  ((int)(Font.Height  *  .75)  *  btnSelected.Text.Length);
        int  ySize  =  Font.Height  +  10;
        btnSelected.Size  =  new  Size(xSize,  ySize);
        btnSelected.Location  =  new  Point(cb.Left,  cb.Bottom  +  ySize);
        btnSelected.Anchor  =  AnchorStyles.Bottom;
        btnSelected.Click  +=  new  EventHandler(btnSelected_Click);

        btnToggle  =  new  Button();
        btnToggle.Parent  =  this;
        btnToggle.Location  =  new  Point((Width  -  cb.Width)  *  7  /  10,
                                                                            cb.Top);
        btnToggle.Text  =  "&Toggle";
        btnToggle.Size  =  new  Size(btnSelected.Width,  btnSelected.Height);
        btnToggle.Anchor  =  AnchorStyles.Bottom;
        btnToggle.Click  +=  new  EventHandler(btnToggle_Click);

        btnExpand  =  new  Button();
        btnExpand.Parent  =  this;
        btnExpand.Location  =  new  Point(btnToggle.Left,  btnToggle.Bottom);
        btnExpand.Text  =  "&Expand";
        btnExpand.Size  =  new  Size(btnSelected.Width,  btnSelected.Height);
        btnExpand.Anchor  =  AnchorStyles.Bottom;
        btnExpand.Click  +=  new  EventHandler(btnExpand_Click);

        btnExpandAll  =  new  Button();
        btnExpandAll.Parent  =  this;
        btnExpandAll.Location  =  new  Point(btnExpand.Left,  btnExpand.Bottom);
        btnExpandAll.Text  =  "Expand  &All";
        btnExpandAll.Size  =  new  Size(btnSelected.Width,  btnSelected.Height);
        btnExpandAll.Anchor  =  AnchorStyles.Bottom;
        btnExpandAll.Click  +=  new  EventHandler(btnExpandAll_Click);

        btnCollapse  =  new  Button();
        btnCollapse.Parent  =  this;
        btnCollapse.Location  =  new  Point(btnExpandAll.Left,  btnExpandAll.Bottom);
        btnCollapse.Text  =  "&Collapse";
        btnCollapse.Size  =  new  Size(btnSelected.Width,  btnSelected.Height);
        btnCollapse.Anchor  =  AnchorStyles.Bottom;
        btnCollapse.Click  +=  new  EventHandler(btnCollapse_Click);

        btnCollapseAll  =  new  Button();
        btnCollapseAll.Parent  =  this;
        btnCollapseAll.Location  =  new  Point(btnCollapse.Left,  btnCollapse.Bottom);
        btnCollapseAll.Text  =  "Colla&pse  All";
        btnCollapseAll.Size  =  new  Size(btnSelected.Width,  btnSelected.Height);
        btnCollapseAll.Anchor  =  AnchorStyles.Bottom;
        btnCollapseAll.Click  +=  new  EventHandler(btnCollapseAll_Click);

        FillDirectoryTree();
    }

    static  void  Main()  
    {
        Application.Run(new  TreeViewDirectories());
    }

    private  void  FillDirectoryTree()
    {
        tvw.BeginUpdate();
        tvw.Nodes.Clear();

        string[]  strDrives  =  Environment.GetLogicalDrives();
                foreach  (string  rootDirectoryName  in  strDrives)
              {
            try  
            {
                Directory.GetDirectories(rootDirectoryName);

                TreeNode  ndRoot  =  new  TreeNode(rootDirectoryName);

                tvw.Nodes.Add(ndRoot);
                if  (ndRoot.Index  %  2  ==  0)
                {
                    ndRoot.BackColor  =  Color.LightYellow;
                    ndRoot.ForeColor  =  Color.Green;
                }

                GetSubDirectoryNodes(ndRoot,  cb.Checked);
            }
            catch    (System.IO.IOException)
            {
                        }
            catch    (Exception  e)
            {
                MessageBox.Show(e.Message);
                        }
        }
          
            tvw.EndUpdate();
          
    }

    private  void  GetSubDirectoryNodes(TreeNode  parentNode,  bool  getFileNames)
    {
        DirectoryInfo  di  =  new  DirectoryInfo(parentNode.FullPath);
        if  ((di.Attributes  &  FileAttributes.Directory)  ==  0)
        {
            return;
        }

        parentNode.Nodes.Clear();

        string[]  arSubs  =  Directory.GetDirectories(parentNode.FullPath);

        foreach  (string  subDir  in  arSubs)
        {
                    DirectoryInfo  dirInfo  =  new  DirectoryInfo(subDir);
                        if  ((dirInfo.Attributes  &  FileAttributes.Hidden)!=  0)
                        {
                              continue;
                        }

            TreeNode  subNode  =  new  TreeNode(dirInfo.Name);
            parentNode.Nodes.Add(subNode);
                
            //    Set  colors  based  on  Index  property.
            if  (subNode.Index  %  2  ==  0)
                subNode.BackColor  =  Color.LightPink;
        }

        if  (getFileNames)
        {
                        //    Get  any  files  for  this  node.
                    string[]  files  =  Directory.GetFiles(parentNode.FullPath);

                        //  After  placing  the  nodes,  
                        //  now  place  the  files  in  that  subdirectory.
                        foreach  (string  str  in  files)
                        {
                FileInfo  fi  =  new  FileInfo(str);
                TreeNode  fileNode  =  new  TreeNode(fi.Name);
                parentNode.Nodes.Add(fileNode);

                //    Set  the  icon
                fileNode.ImageIndex  =  0;
                fileNode.SelectedImageIndex  =  3;

                //    Set  colors  based  on  Index  property.
                if  (fileNode.Index  %  2  ==  0)
                    fileNode.BackColor  =  Color.LightGreen;
                        }
        }
    }    //  close  GetSubDirectoryNodes



    private  void  cb_CheckedChanged(object  sender,  EventArgs  e)
    {
        FillDirectoryTree();
    }

    private  void  tvw_BeforeExpand(object  sender,  
                                TreeViewCancelEventArgs  e)
    {
        tvw.BeginUpdate();

        foreach  (TreeNode  tn  in  e.Node.Nodes)
        {
            GetSubDirectoryNodes(tn,  cb.Checked);
        }

        tvw.EndUpdate();            
    }        

    private  void  btnSelected_Click(object  sender,  EventArgs  e)
    {
        MessageBox.Show(tvw.SelectedNode.ToString()  +  "\n"  +
                "FullPath:\t"  +  tvw.SelectedNode.FullPath.ToString()  +  "\n"  +
                      "Index:\t"  +  tvw.SelectedNode.Index.ToString());
    }

    private  void  btnExpand_Click(object  sender,  EventArgs  e)
    {
        tvw.SelectedNode.Expand();
    }

    private  void  btnExpandAll_Click(object  sender,  EventArgs  e)
    {
        tvw.SelectedNode.ExpandAll();
    }

    private  void  btnCollapse_Click(object  sender,  EventArgs  e)
    {
        tvw.SelectedNode.Collapse();
    }

    private  void  btnCollapseAll_Click(object  sender,  EventArgs  e)
    {
        tvw.CollapseAll();
    }

    private  void  btnToggle_Click(object  sender,  EventArgs  e)
    {
        tvw.SelectedNode.Toggle();
    }
}