动态添加节点

今天练习了一个动态添加更新树的例子，具体实现如下：新建Form应用程序，添加treeview,textbox,以及四个button控件：

具体代码如下：

private void button1_Click(object sender, EventArgs e)
        {
            TreeNode newNode = new TreeNode(this.textBox1.Text,0,0);
            this.treeView1.Nodes.Add(newNode);
            this.treeView1.Select();
        }

        private void button2_Click(object sender, EventArgs e)
        {
            TreeNode selectedNode = this.treeView1.SelectedNode;

            if(selectedNode == null)
            {
                MessageBox.Show(this,"添加子结点之前必须先选中一个根节点。","提示信息",MessageBoxButtons.OK,MessageBoxIcon.Warning);
                return;
                            
            }

            TreeNode newNode = new TreeNode(this.textBox1.Text,1,1);
            selectedNode.Nodes.Add(newNode);
            selectedNode.SelectedImageIndex = 1;
            selectedNode.Expand();
            this.treeView1.Select();
        }

        private void button3_Click(object sender, EventArgs e)
        {
            TreeNode selectedNode = this.treeView1.SelectedNode;
            if(selectedNode == null)
            {
                MessageBox.Show(this,"删除结点之前必须选中一个结点.","提示信息",MessageBoxButtons.OK,MessageBoxIcon.Warning);
                return;
                        
            }
            TreeNode parentNode = selectedNode.Parent;
            if (parentNode == null)
            {
                this.treeView1.Nodes.Remove(selectedNode);


            }
            else
            {

                parentNode.Nodes.Remove(selectedNode);
                if(parentNode.Nodes.Count == 0)
                {
                    parentNode.ImageIndex = 1;
                    parentNode.SelectedImageIndex = 1;
                
                        
                
                }
            
            
            
            }
            this.treeView1.Select();
        }

        private void treeView1_AfterSelect(object sender, TreeViewEventArgs e)
        {
            int str = treeView1.SelectedImageIndex;
            
            //listBox1.Items.Add(str.ToString());
        }

        private void button4_Click(object sender, EventArgs e)
        {
            TreeNode selectNode = this.treeView1.SelectedNode;
            if(selectNode != null)
            {
                this.treeView1.SelectedNode.Text = textBox1.Text;
            
            }




        }
    }