C# TreeView 控件的综合使用方法

1、概述

    该篇文章开发使用的语言c#，环境visualstudio2010,sql数据库.主要内容包括：

（1）treeView控件添加根节点、子节点的基本方法，节点的删除。

（2）把treeView控件的节点数据保存的SQL数据包括中，把数据库数据表中的数据动态加载到treeView控件中，控件节点的递归删除（指的是递归删除数据表的数据）

2、TreeView控件的基本用法

     为了演示相关方法、属性的用法，通过vs2010创建一个winform项目，在项目中添加一个窗体，其布局如图2-1所示

图2-1

其中TreeView控件的名称为：treeview1,文本框的名称为：txtNodeName，“添加根节点”按钮的名称为：btnAddRootNode，“添加子节点”按钮的名称为：btnAddSonNode，“删除选中节点”按钮的名称：btnDelete

添加节点、删除节点的代码如下所示：

2.1添加根节点

private void btnAddRootNode_Click(object sender, EventArgs e)
{
//要添加的节点名称为空，即文本框是否为空
if(string.IsNullOrEmpty(txtNodeName.Text.Trim()))
{
MessageBox.Show("要添加的节点名称不能为空！");
return;
}
//添加根节点
treeView1.Nodes.Add(txtNodeName.Text.Trim());
txtNodeName.Text = "";
}

添加根节点代码

 1 private void btnAddRootNode_Click(object sender, EventArgs e)
 2   {
 3       //要添加的节点名称为空，即文本框是否为空
 4         if(string.IsNullOrEmpty(txtNodeName.Text.Trim()))
 5          {
 6              MessageBox.Show("要添加的节点名称不能为空！");
 7              return;
 8          }
 9             //添加根节点
10             treeView1.Nodes.Add(txtNodeName.Text.Trim());
11            txtNodeName.Text = "";
12   }

2.2添加子节点

private void btnAddSonNode_Click(object sender, EventArgs e)
{
//要添加的节点名称为空，即文本框是否为空
if (string.IsNullOrEmpty(txtNodeName.Text.Trim()))
{
MessageBox.Show("要添加的节点名称不能为空！");
return;
}
if(treeView1.SelectedNode==null)
{
MessageBox.Show("请选择要添加子节点的节点！");
return;
} treeView1.SelectedNode.Nodes.Add(txtNodeName.Text.Trim());
txtNodeName.Text = "";
}

添加子节点代码

 1 private void btnAddSonNode_Click(object sender, EventArgs e)
 2    {
 3        //要添加的节点名称为空，即文本框是否为空
 4         if (string.IsNullOrEmpty(txtNodeName.Text.Trim()))
 5          {
 6              MessageBox.Show("要添加的节点名称不能为空！");
 7               return;
 8          }
 9          if(treeView1.SelectedNode==null)
10           {
11              MessageBox.Show("请选择要添加子节点的节点！");
12               return;
13           }               treeView1.SelectedNode.Nodes.Add(txtNodeName.Text.Trim());
14     txtNodeName.Text = "";
15    }

2.3删除选中节点

private void btnDelete_Click(object sender, EventArgs e)
{
if (treeView1.SelectedNode == null)
{
MessageBox.Show("请选择要删除的节点！");
return;
}
treeView1.SelectedNode.Remove();
}

删除选中节点代码

1  private void btnDelete_Click(object sender, EventArgs e)
2   {
3       if (treeView1.SelectedNode == null)
4          {
5               MessageBox.Show("请选择要删除的节点！");
6               return;
7          }
8             treeView1.SelectedNode.Remove();
9   }

3、TreeView控件在树形菜单中的应用

    Treeview在产品类别管理、部门管理等树状多级菜单中的应用，主要包括把树控件中的数据保存到SQL数据表中，把数据表中的数据动态加载到treeview控件中，以及删除控件节点及数据表中的数据。

3.1数据表

create table TreeTest
(
 id int identity(1,1) primary key not null,//节点id
 nodeName nvarchar(50) not null,//节点名称
 parentId int not null//节点父id
)

create table TreeTest
(
 id int identity(1,1) primary key not null,//节点id
 nodeName nvarchar(50) not null,//节点名称
 parentId int not null//节点父id
)

3.2把节点数据存储到数据表

    把treeView添加的节点信息存储到数据表，包括根节点、子节点，所用的窗体界面如图2-1所示，控件的名称保持不变，只是执行代码变了。

private void btnAddRootNode_Click (object sender, EventArgs e)
{
if(string.IsNullOrEmpty(txtNodeName.Text.Trim()))
{
MessageBox.Show("请填写要添加的节点名称！");
return;
}
string sql = "insert into TreeTest(nodeName,parentId) output inserted.id values"+"("+" "+"'"+ txtNodeName.Text.Trim()+"'"+","+"'"+0+"'"+")";
int id = (int)sqlHelper.ExecuteScalar(sql);
TreeNode node1 = new TreeNode();
node1.Tag = id;//把自己的id存放在该节点tag对象里
node1.Text = txtNodeName.Text.Trim();
treeView1.Nodes.Add(node1);
txtNodeName.Text = "";
}

添加根节点

 1  private void btnAddRootNode_Click (object sender, EventArgs e)
 2   {
 3         if(string.IsNullOrEmpty(txtNodeName.Text.Trim()))
 4          {
 5              MessageBox.Show("请填写要添加的节点名称！");
 6               return;
 7          }
 8   string sql = "insert into TreeTest(nodeName,parentId) output inserted.id values"+"("+" "+"'"+ txtNodeName.Text.Trim()+"'"+","+"'"+0+"'"+")";
 9             int id = (int)sqlHelper.ExecuteScalar(sql);
10             TreeNode node1 = new TreeNode();
11             node1.Tag = id;//把自己的id存放在该节点tag对象里
12             node1.Text = txtNodeName.Text.Trim();
13             treeView1.Nodes.Add(node1);
14             txtNodeName.Text = "";
15         }

private void btnAddSonNode_Click (object sender, EventArgs e)
{
int id;
if(string.IsNullOrEmpty(txtNodeName.Text.Trim()))
{
return;
}
if(treeView1.SelectedNode==null)
{
MessageBox.Show("请选择父节点");
return;
}
id =(int)treeView1.SelectedNode.Tag;//获取父id
string sql = "insert into TreeTest(nodeName,parentId) output inserted.id values"+"(" + " " + "'" + txtNodeName.Text.Trim() + "'" + "," + "'" + id + "'" + ")";
int id1 = (int)sqlHelper.ExecuteScalar(sql);
TreeNode node1 = new TreeNode();
node1.Tag = id1;
node1.Text = txtNodeName.Text.Trim();
treeView1.SelectedNode.Nodes.Add(node1);
txtNodeName.Text = "";
}

添加子节点

 1 private void btnAddSonNode_Click (object sender, EventArgs e)
 2    {
 3             int id;
 4             if(string.IsNullOrEmpty(txtNodeName.Text.Trim()))
 5             {
 6                 return;
 7             }
 8             if(treeView1.SelectedNode==null)
 9             {
10                 MessageBox.Show("请选择父节点");
11                 return;
12             }
13             id =(int)treeView1.SelectedNode.Tag;//获取父id
14             string sql = "insert into TreeTest(nodeName,parentId) output inserted.id values"+"(" + " " + "'" + txtNodeName.Text.Trim() + "'" + "," + "'" + id + "'" + ")";
15             int id1 = (int)sqlHelper.ExecuteScalar(sql);
16             TreeNode node1 = new TreeNode();
17             node1.Tag = id1;
18             node1.Text = txtNodeName.Text.Trim();
19             treeView1.SelectedNode.Nodes.Add(node1);
20             txtNodeName.Text = "";
21  }

3.3动态加载数据

    把数据表中的数据动态加载到treeView控件中，在treeView所在窗体的load事件中加载，相应的代码如下所示

private void Form3_Load(object sender, EventArgs e)
{
//加载数据，把数据加载到控件treeview1中
setTreeView(treeView1, 0);
}

//调用的时候parentId以0值开始 setTreeView(treeView1, 0);
private void setTreeView(TreeView tr1,int parentId)
{
string sql = "select * from TreeTest where parentId=" + parentId;
DataTable ds= sqlHelper.ExecuteDataTable(sql);
if (ds.Rows.Count > 0)
{
int pId = -1;
foreach (DataRow row in ds.Rows)
{
TreeNode node = new TreeNode();
node.Text = row["nodeName"].ToString();
node.Tag = (int)row["id"];
pId = (int)row["parentId"];
if (pId == 0)
{
//添加根节点
tr1.Nodes.Add(node);
}
else
{
//添加根节点之外的其他节点
RefreshChildNode(tr1,node,pId);
}
//查找以node为父节点的子节点
setTreeView(tr1,(int)node.Tag);

}
}

}
//处理根节点的子节点
private void RefreshChildNode(TreeView tr1,TreeNode treeNode, int parentId)
{
foreach (TreeNode node in tr1.Nodes)
{
if((int)node.Tag==parentId)
{
node.Nodes.Add(treeNode);
return;
}else if (node.Nodes.Count > 0)
{
FindChildNode(node, treeNode, parentId);
}
}
}

//处理根节点的子节点的子节点
private void FindChildNode(TreeNode tNode,TreeNode treeNode, int parentId)
{
foreach (TreeNode node in tNode.Nodes)
{
if ((int)node.Tag == parentId)
{
node.Nodes.Add(treeNode);
return;
}else if (node.Nodes.Count > 0)
{
FindChildNode(node,treeNode,parentId);
}

}

}

动态加载数据代码

 1 private void Form3_Load(object sender, EventArgs e)
 2  {      
 3      //加载数据，把数据加载到控件treeview1中   
 4      setTreeView(treeView1, 0);           
 5  }
 6 
 7  //调用的时候parentId以0值开始 setTreeView(treeView1, 0);
 8   private void setTreeView(TreeView tr1,int parentId)
 9  {
10   string sql = "select * from TreeTest where parentId=" + parentId;
11       DataTable ds= sqlHelper.ExecuteDataTable(sql);
12        if (ds.Rows.Count > 0)
13         {
14                int pId = -1;
15              foreach (DataRow row in ds.Rows)
16                {
17                     TreeNode node = new TreeNode();
18                     node.Text = row["nodeName"].ToString();
19                     node.Tag = (int)row["id"];
20                     pId = (int)row["parentId"];
21                     if (pId == 0)
22                     {
23                         //添加根节点
24                         tr1.Nodes.Add(node);
25                     }
26                     else
27                     {
28                         //添加根节点之外的其他节点
29                         RefreshChildNode(tr1,node,pId);
30                     }
31                     //查找以node为父节点的子节点
32                     setTreeView(tr1,(int)node.Tag);
33 
34                 }
35             }
36 
37    }
38 //处理根节点的子节点
39   private void RefreshChildNode(TreeView tr1,TreeNode treeNode, int parentId)
40  {
41          foreach (TreeNode node in tr1.Nodes)
42             {
43                 if((int)node.Tag==parentId)
44                 {
45                     node.Nodes.Add(treeNode);
46                     return;
47                 }else if (node.Nodes.Count > 0)
48                 {
49                     FindChildNode(node, treeNode,  parentId);
50                 }
51             }
52  }
53 
54   //处理根节点的子节点的子节点
55   private void FindChildNode(TreeNode  tNode,TreeNode treeNode, int parentId)
56  {
57          foreach (TreeNode node in tNode.Nodes)
58           {
59                 if ((int)node.Tag == parentId)
60                 {
61                     node.Nodes.Add(treeNode);
62                     return;
63                 }else if (node.Nodes.Count > 0)
64                 {
65                     FindChildNode(node,treeNode,parentId);
66                 }
67 
68             }
69 
70 }

3.4、递归删除节点，这里指的是递归删除节点在数据表中的信息

private void btnDelete_Click(object sender, EventArgs e)
{
if(treeView1.SelectedNode==null)
{
MessageBox.Show("请选择要删除的节点！");
return;
}
//选中节点的id，也是其子节点的parentId
int id = (int)treeView1.SelectedNode.Tag;
nodeDelete(id);//递归删除数据表中的数据
treeView1.SelectedNode.Remove();//删除控件中的节点

}
//数据表中的数据的递归删除方法
public void nodeDelete(int id)
{
string sql = "select * from TreeTest where parentId="+id;
DataTable ds = sqlHelper.ExecuteDataTable(sql);
if (ds.Rows.Count > 0)
{
//有子节点
foreach(DataRow row in ds.Rows)
{
//先删除父节点
string delete = "delete from TreeTest where id=" + id;
int k = sqlHelper.ExecuteNonQuery(delete);
//查找子节点，删除
int id1 = (int)row["id"];
nodeDelete(id1);
}
}
else
{
//没有子节点
string delete = "delete from TreeTest where id="+id;
int k = sqlHelper.ExecuteNonQuery(delete);
}
}

删除节点代码

 1  private void btnDelete_Click(object sender, EventArgs e)
 2    {
 3          if(treeView1.SelectedNode==null)
 4          {
 5                 MessageBox.Show("请选择要删除的节点！");
 6                 return;
 7            }
 8             //选中节点的id，也是其子节点的parentId
 9             int id = (int)treeView1.SelectedNode.Tag;
10             nodeDelete(id);//递归删除数据表中的数据
11             treeView1.SelectedNode.Remove();//删除控件中的节点
12 
13   }
14    //数据表中的数据的递归删除方法
15    public void nodeDelete(int id)
16  {
17             string sql = "select * from TreeTest where parentId="+id;
18             DataTable ds = sqlHelper.ExecuteDataTable(sql);
19             if (ds.Rows.Count > 0)
20             {
21                 //有子节点
22                 foreach(DataRow row in ds.Rows)
23                 {
24                     //先删除父节点
25                     string delete = "delete from TreeTest where id=" + id;
26                     int k = sqlHelper.ExecuteNonQuery(delete);
27                     //查找子节点，删除
28                     int id1 = (int)row["id"];
29                     nodeDelete(id1);
30                 }
31             }
32             else
33             { 
34                //没有子节点
35                 string delete = "delete from TreeTest where id="+id;
36                 int k = sqlHelper.ExecuteNonQuery(delete);
37             }
38 }

4、TreeView控件的右键操作

TreeView控件的右键操作，需要两个winform窗体form3（图4-1），form4（图4-2），其中form3中放置treeview1控件，两个contextMenuStrip，contextMenuStrip1和contextMenuStrip2，

form4用于弹出菜单 填写要添加节点名称

图4-1

图4-2

contextMenuStrip1

contextMenuStrip2

4.1 Form4窗体的代码如下：

public partial class Form4 : Form
{
public string nodeName
{
get { return textBox1.Text.Trim(); }
}
public Form4()
{
InitializeComponent();
}

private void btnCancel_Click(object sender, EventArgs e)
{
DialogResult = DialogResult.Cancel;
}

private void btnConfirm_Click(object sender, EventArgs e)
{
if(string.IsNullOrEmpty(textBox1.Text.Trim()))
{
MessageBox.Show("请填写节点名称！");
return;
}
DialogResult = DialogResult.OK;
}
}

form4窗体代码

 1 public partial class Form4 : Form
 2  {
 3         public string nodeName
 4         {
 5             get { return textBox1.Text.Trim(); }
 6         }
 7         public Form4()
 8         {
 9             InitializeComponent();
10         }
11 
12         private void btnCancel_Click(object sender, EventArgs e)
13         {
14             DialogResult = DialogResult.Cancel;
15         }
16 
17         private void btnConfirm_Click(object sender, EventArgs e)
18         {
19             if(string.IsNullOrEmpty(textBox1.Text.Trim()))
20             {
21                 MessageBox.Show("请填写节点名称！");
22                 return;
23             }
24             DialogResult = DialogResult.OK;
25         }
26 }

4.2 form3窗体的代码如下：

public partial class Form3 : Form
{
public Form3()
{
InitializeComponent();
}
private void treeView1_MouseDown(object sender, MouseEventArgs e)
{
if(e.Button==MouseButtons.Right)
{
Point ClickPoint = new Point(e.X, e.Y);
int x = e.X;
int y = e.Y;
TreeNode CurrentNode = treeView1.GetNodeAt(ClickPoint);
if (CurrentNode is TreeNode)//判断你点的是不是一个节点
{
treeView1.SelectedNode = CurrentNode;
CurrentNode.ContextMenuStrip = this.contextMenuStrip1;
contextMenuStrip1.Show(MousePosition);
}
else
{
treeView1.ContextMenuStrip = this.contextMenuStrip2;
contextMenuStrip2.Show(MousePosition);
}
}
}

private void 添加子节点ToolStripMenuItem_Click(object sender, EventArgs e)
{
Form4 f5 = new Form4();
if (f5.ShowDialog() == DialogResult.OK)
{
treeView1.SelectedNode.Nodes.Add(f5.nodeName);
}
}

private void 删除选中节点ToolStripMenuItem_Click(object sender, EventArgs e)
{
treeView1.SelectedNode.Remove();
}

private void 添加根节点ToolStripMenuItem1_Click(object sender, EventArgs e)
{
Form4 f4 = new Form4();
if (f4.ShowDialog() == DialogResult.OK)
{
treeView1.Nodes.Add(f4.nodeName);
}
}

private void 清空ToolStripMenuItem1_Click(object sender, EventArgs e)
{
treeView1.Nodes.Clear();
}
}

form3窗体代码

 1 public partial class Form3 : Form
 2     {
 3         public Form3()
 4         {
 5             InitializeComponent();
 6         }
 7         private void treeView1_MouseDown(object sender, MouseEventArgs e)
 8         {
 9             if(e.Button==MouseButtons.Right)
10             {
11                 Point ClickPoint = new Point(e.X, e.Y);
12                 int x = e.X;
13                 int y = e.Y;
14                 TreeNode CurrentNode = treeView1.GetNodeAt(ClickPoint);
15                 if (CurrentNode is TreeNode)//判断你点的是不是一个节点
16                 {               
17                     treeView1.SelectedNode = CurrentNode;
18                     CurrentNode.ContextMenuStrip = this.contextMenuStrip1;                    
19                     contextMenuStrip1.Show(MousePosition);
20                 }
21                 else
22                 {
23                     treeView1.ContextMenuStrip = this.contextMenuStrip2;
24                     contextMenuStrip2.Show(MousePosition);
25                 }
26             }
27         }
28 
29         private void 添加子节点ToolStripMenuItem_Click(object sender, EventArgs e)
30         {
31             Form4 f5 = new Form4();
32             if (f5.ShowDialog() == DialogResult.OK)
33             {
34               treeView1.SelectedNode.Nodes.Add(f5.nodeName);
35             }
36         }
37 
38         private void 删除选中节点ToolStripMenuItem_Click(object sender, EventArgs e)
39         {
40             treeView1.SelectedNode.Remove();
41         }
42 
43         private void 添加根节点ToolStripMenuItem1_Click(object sender, EventArgs e)
44         {
45             Form4 f4 = new Form4();
46             if (f4.ShowDialog() == DialogResult.OK)
47             {
48                 treeView1.Nodes.Add(f4.nodeName);
49             }
50         }
51 
52         private void 清空ToolStripMenuItem1_Click(object sender, EventArgs e)
53         {
54             treeView1.Nodes.Clear();
55         }
56     }