实现方式一：

通过代码方式实现如下所示：

private string FilePath = Application.StartupPath + "\\Images\\";              Image img = new Bitmap(FilePath + "one.ico");            Image img1 = new Bitmap(FilePath + "two.ico");            ImageList imgs = new ImageList();            imgs.Images.Add(img);            imgs.Images.Add(img1);            this.tvTest.ImageList = imgs;            TreeNode node = new TreeNode();            node.Text = "Root";            this.tvTest.Nodes.Add(node);            node.ImageIndex = 0;            node.SelectedImageIndex = 0;            TreeNode node1 = new TreeNode();            node1.Text = "root001";            TreeNode node2 = new TreeNode();            node2.Text = "root002";            node.Nodes.Add(node1);            node.Nodes.Add(node2);            this.tvTest.ExpandAll();            node1.ImageIndex =1;            node1.SelectedImageIndex = 1;            node2.ImageIndex = 1;            node2.SelectedImageIndex = 1;

实现方式二：

通过绑定ImageList控件实现，如下所示：

操作步骤：第一步，工具箱中拖动ImageList控件；第二步，ImageList控件Images属性添加图片集合；第三步，TreeView控件绑定ImageList属性；

第四步，代码如下所示：

TreeNode node = new TreeNode();            node.Text = "Root";            this.tvTest.Nodes.Add(node);            node.ImageIndex = 0;            node.SelectedImageIndex = 0;            TreeNode node1 = new TreeNode();            node1.Text = "root001";            TreeNode node2 = new TreeNode();            node2.Text = "root002";            node.Nodes.Add(node1);            node.Nodes.Add(node2);            this.tvTest.ExpandAll();            node1.ImageIndex =1;            node1.SelectedImageIndex = 1;            node2.ImageIndex = 1;            node2.SelectedImageIndex = 1;

运行效果如下：