How to extract Information from Nodes in TreeView in Windows forms?

Question

I have created a Winform. I want to show Subanatomy ID information using object of type Subanatomy after the node is selected how Should I do it.? i have used all the neccessary libraries in my original code

`    using System.Windows.Forms;
 using basicObjectLib;

namespace WindowsFormsApplication12
{
public partial class Form1 : Form
{



    public Form1()
    {
        InitializeComponent();
        LoadTreeItems();
 }

    public void LoadTreeItems()
    {
        // Dummy Data 
        // created a DLL Basic Class Object Conatining class definitions of anatomy subanatomy 
        #region Object
        Anatomy an1 = new Anatomy();
        an1.AnatomyID = 1;
        an1.AnatomyName = "Anatomy1";

        Subanatomy san1 = new Subanatomy();
        san1.SubAnatomyID = 11;
        san1.SubAnatomyName = "subAn1";
        an1.SubanatomyList.Add(san1);

        Subanatomy san2 = new Subanatomy();
        san2.SubAnatomyName = "subAn2";
        san2.SubAnatomyID = 2;
        an1.SubanatomyList.Add(san2);


        Anatomy an2 = new Anatomy();
        an2.AnatomyID = 2;
        an2.AnatomyName = "Anatomy2";

        Subanatomy san21 = new Subanatomy();
        san21.SubAnatomyName = "subAn1";
        san21.SubAnatomyID = 21;
        an2.SubanatomyList.Add(san21);

        Subanatomy san22 = new Subanatomy();
        san22.SubAnatomyName = "subAn2";
        san22.SubAnatomyID = 22;
        an2.SubanatomyList.Add(san22);


        Anatomy an3 = new Anatomy();
        an3.AnatomyID = 3;
        an3.AnatomyName = "Anatomy3";

        Subanatomy san31 = new Subanatomy();
        san31.SubAnatomyName = "subAn1";
        san31.SubAnatomyID = 31;
        an3.SubanatomyList.Add(san31);

        Subanatomy san32 = new Subanatomy();
        san32.SubAnatomyName = "subAn2";
        san32.SubAnatomyID = 32;
        an3.SubanatomyList.Add(san32);

        List<Anatomy> anatomyObj = new List<Anatomy>();
        anatomyObj.Add(an1);
        anatomyObj.Add(an2);
        anatomyObj.Add(an3);
        #endregion

        foreach(Anatomy obj in anatomyObj)
        {
            TreeNode parentNode = new TreeNode();
           parentNode = new TreeNode(obj.AnatomyName);

            treeView1.Nodes.Add(parentNode);
            foreach(Subanatomy subObj in obj.SubanatomyList)
            {
                TreeNode childNode = new TreeNode();
                childNode = new TreeNode(subObj.SubAnatomyName);

                parentNode.Nodes.Add(childNode);
            }
        }


    }
    private void treeView1_AfterSelect(object sender, TreeViewEventArgs e)
    {

        if (e.Action == TreeViewAction.ByMouse)
        {
            // name of treeNode
            textBox4.Text = treeView1.SelectedNode.Name.ToString();
            // to show the ID
            textBox2.Text = "";
        }
    }

    private void button1_Click(object sender, EventArgs e)
    {
        treeView1.ExpandAll();
    }
  }
  public class WindowsFormApplication
  {
    public static void main()
    {
        Form1 _treeviewDemo = new Form1();

    }
 }
}`

Answer 1

In your code:

foreach(Subanatomy subObj in obj.SubanatomyList)
        {
            TreeNode childNode = new TreeNode();
            childNode = new TreeNode(subObj.SubAnatomyName) { Tag = subjObj.SubAnatomyID  };

            parentNode.Nodes.Add(childNode);
        }

and get data

 private void treeView1_AfterSelect(object sender, TreeViewEventArgs e)
{

    if (e.Action == TreeViewAction.ByMouse)
    {
        // name of treeNode
        textBox4.Text = treeView1.SelectedNode.Name.ToString();
        // to show the ID
        textBox2.Text = ((int)treeView1.SelectedNode.Tag).ToString();
    }
}

But I think better is

foreach(Subanatomy subObj in obj.SubanatomyList)
        {
            TreeNode childNode = new TreeNode();
            childNode = new TreeNode(subObj.SubAnatomyName) { Tag = subjObj  };

            parentNode.Nodes.Add(childNode);
        }

and

  private void treeView1_AfterSelect(object sender, TreeViewEventArgs e)
{

    if (e.Action == TreeViewAction.ByMouse)
    {
        Subanatomy suba = treeView1.SelectedNode.Tag as Subanatomy;
        if (suba != null)
        {
          // name of treeNode
          textBox4.Text = subA.SubAnatomyName;
          // to show the ID
          textBox2.Text = subA.SubAnatomyID.ToString();
        }
    }
}

Answer 2

you can use TreeNode.Tag to store your object.

when you create a TreeNode, assign the object you want to associate it with to the TreeNode Example:

 treeNode.Tag=<object>

you can use it later by casting it

Example:

 (<Class>)treeNode.Tag