try
            {
                string path = Application.StartupPath.Substring(0, Application.StartupPath.IndexOf("\\bin"));
                il.Images.Add(new Icon(path + "\\Image\\image1.ico"));
                il.Images.Add(new Icon(path + "\\Image\\image2.ico"));
                il.Images.Add(new Icon(path + "\\Image\\image3.ico"));
                System.Drawing.Image myImage = Image.FromFile(path + "\\Image\\image4.gif");
                il.Images.Add(myImage);
            }
            catch (FileNotFoundException ex)
            {
                MessageBox.Show(ex.Message, "Attenzione");
            }
            catch (ArgumentOutOfRangeException arg)
            {
                MessageBox.Show(arg.Message, "Attenzione");
            }
            tv_Main.ImageList = il;
            for (int iCount = 0; iCount < tv_Main.Nodes.Count; iCount++)
            {
                if (tv_Main.Nodes[iCount].Text.ToUpper().Contains(str.ToUpper()))
                {
                    tv_Main.SelectedNode = tv_Main.Nodes[iCount];
                    tv_Main.Select();
                    tv_Main.Nodes[iCount].ImageIndex = 1;
                    tv_Main.Nodes[iCount].SelectedImageIndex = 1;
                }
                else
                {
                    tv_Main.SelectedNode = tv_Main.Nodes[iCount];
                    tv_Main.Select();
                    tv_Main.Nodes[iCount].ImageIndex = -1;
                    tv_Main.Nodes[iCount].SelectedImageIndex = -1;
                }
            }