TreeView
This displays text and icon data. TreeView
must have nodes added to it through the Nodes collection. It represents hierarchical text and icon data in a convenient way.
We add a TreeView
control to the Windows Forms Application project. To do this, open the Toolbox panel by clicking on the View and then Toolbox menu item in Visual Studio.
Double
-click on the Form1
window to create the Form1_Load
event. In this event handler, we will insert code to build the nodes in the TreeView
control.
Form1_Load
event, double-click on the window of the program in the Visual Studio designer.Nodes.Add()
call adds a node instance to the treeView1
instance of the TreeView
that exists.TreeNode
to add a node to the TreeView
.using System; using System.Windows.Forms; namespace WindowsFormsApplication23 { public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void Form1_Load(object sender, EventArgs e) { // // This is the first node in the view. // TreeNode treeNode = new TreeNode("Windows"); treeView1.Nodes.Add(treeNode); // // Another node following the first node. // treeNode = new TreeNode("Linux"); treeView1.Nodes.Add(treeNode); // // Create two child nodes and put them in an array. // ... Add the third node, and specify these as its children. // TreeNode node2 = new TreeNode("C#"); TreeNode node3 = new TreeNode("VB.NET"); TreeNode[] array = new TreeNode[] { node2, node3 }; // // Final node. // treeNode = new TreeNode("Dot Net Perls", array); treeView1.Nodes.Add(treeNode); } } }
We can add a double-click event handler to your TreeView
program. This means that when the user double
-clicks on an item, you can execute code based on that node.
MouseDoubleClick
event handler, right-click the TreeView
in the designer and select Properties.Select
"MouseDoubleClick
" and click twice on that entry. You can then change treeView1_MouseDoubleClick
, which was generated.using System; using System.Windows.Forms; namespace WindowsFormsApplication23 { public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void Form1_Load(object sender, EventArgs e) { // Insert code here. [OMIT] } private void treeView1_MouseDoubleClick(object sender, MouseEventArgs e) { // // Get the selected node. // TreeNode node = treeView1.SelectedNode; // // Render message box. // MessageBox.Show(string.Format("You selected: {0}", node.Text)); } } }
SelectedNode
propertyIn the treeView1_MouseDoubleClick
method, you can see that the SelectedNode
property is accessed on the treeView1
control.
The treeView1_MouseDoubleClick
event handler also accesses the Text instance property on the treeView1
control.
string
that represents the text in the TreeNode
.MessageBox
is shown with that text.We added TreeNode
references and children nodes to a TreeView
. Next, we added an event handler, which enables primitive interaction with the TreeView
nodes by the user.