How to use TreeView in WinForms?

Using the TreeView control in WinForms is quite simple. Here is a basic example of how to use it:

1. Create a new Windows Forms application project in Visual Studio.
2. Open the form designer and drag the TreeView control onto the form.
3. Double click on the TreeView control and add the following code to the Form1_Load event handler in the Form1.cs file.

private void Form1_Load(object sender, EventArgs e)
{
    treeView1.Nodes.Add("Node 1");
    treeView1.Nodes.Add("Node 2");
    treeView1.Nodes.Add("Node 3");

    TreeNode parentNode = new TreeNode("Parent Node");
    treeView1.Nodes.Add(parentNode);

    parentNode.Nodes.Add("Child Node 1");
    parentNode.Nodes.Add("Child Node 2");

    TreeNode grandparentNode = new TreeNode("Grandparent Node");
    parentNode.Nodes.Add(grandparentNode);

    grandparentNode.Nodes.Add("Grandchild Node 1");
    grandparentNode.Nodes.Add("Grandchild Node 2");
}

1. When you run the program, you can see that the TreeView control displays a tree structure of nodes.

By following these steps, you can easily create a tree structure in a WinForms application using the TreeView control. You can add, delete, or modify nodes as needed to create more complex tree structures.