adding child nodes in treeview

Question

I m new to C  and don t have any programming experience  But I ve finish a C  basics  Now I would like to design a simple tree view by adding parent node and child node   I would like to add a second child for the Second node  I m quite stuck here and don t know what s next   Any ideas   Here is the code       private void addParentNode Click object sender  EventArgs e                string yourParentNode          yourParentNode   textBox1 Text Trim            treeView2 Nodes Add yourParentNode              private void addChildNode Click object sender  EventArgs e                string yourChildNode          yourChildNode   textBox1 Text Trim            treeView2 Nodes 0  Nodes Add yourChildNode           Sorry I wasn t clear  I m not sure if I really need this one here        treeView1 BeginUpdate         treeView1 Nodes Clear      What I m trying to do  is to add Parent Nodes and child node  In my code  I can add several Parent Nodes  but if I want to add a child node  it only add in the first parent node   I want that if I add a child node  I want to add it to the second parent or third parent   In my code I only use one treeview here which names as treeview2 Here is the screenshot  this is how my final code looks like  Before I put the else  I m getting an error if I don t select anything  So I made it that way that if there is nothing selected it will add the  child node  to the  default node  or  parent1 node   It seems to work good  Thanks guys -         This is for adding a parent node     private void addParentNode Click object sender  EventArgs e                treeView2 BeginUpdate             string yourParentNode          yourParentNode   textBox1 Text Trim            treeView2 Nodes Add yourParentNode           treeView2 EndUpdate                 This is for adding child node     private void addChildNode Click object sender  EventArgs e                if  treeView2 SelectedNode    null                        string yourChildNode              yourChildNode   textBox1 Text Trim                 treeView2 SelectedNode Nodes Add yourChildNode               treeView2 ExpandAll                        This is for adding the child node to the default node parent 1 node          else                       string yourChildNode              yourChildNode   textBox1 Text Trim                treeView2 Nodes 0  Nodes Add yourChildNode               Additional question  Are there any other ways on how the code be better  Because here  I declare the string  yourChildNode  twice  One in the if and other one in the else  are there any simplification

User · Answer

May i add to Stormenet example some KISS (Keep It Simple & Stupid):

If you already have a treeView or just created an instance of it: Let's populate with some data - Ex. One parent two child's :

            treeView1.Nodes.Add("ParentKey","Parent Text");
            treeView1.Nodes["ParentKey"].Nodes.Add("Child-1 Text");
            treeView1.Nodes["ParentKey"].Nodes.Add("Child-2 Text");

Another Ex. two parent's first have two child's second one child:

            treeView1.Nodes.Add("ParentKey1","Parent-1  Text");
            treeView1.Nodes.Add("ParentKey2","Parent-2 Text");
            treeView1.Nodes["ParentKey1"].Nodes.Add("Child-1 Text");
            treeView1.Nodes["ParentKey1"].Nodes.Add("Child-2 Text");
            treeView1.Nodes["ParentKey2"].Nodes.Add("Child-3 Text");

Take if farther - sub child of child 2:

            treeView1.Nodes.Add("ParentKey1","Parent-1  Text");
            treeView1.Nodes["ParentKey1"].Nodes.Add("Child-1 Text");
            treeView1.Nodes["ParentKey1"].Nodes.Add("ChildKey2","Child-2 Text");
            treeView1.Nodes["ParentKey1"].Nodes["ChildKey2"].Nodes.Add("Child-3 Text");

As you see you can have as many child's and parent's as you want and those can have sub child's of child's and so on.... Hope i help!

User · Answer

SqlConnection con   new SqlConnection   Data Source NIKOLAY Initial Catalog PlanZadanie Integrated Security True            SqlCommand cmd   new SqlCommand            DataTable dt   new DataTable            public void loadTree TreeView tree                        cmd Connection   con              cmd CommandType   CommandType Text              cmd CommandText    SELECT  RAZDEL ID   NAME RAZDEL  FROM  tbl RAZDEL                try                               con Open                    SqlDataReader reader   cmd ExecuteReader                    while  reader Read                                          tree Nodes Add reader GetString 1                        tree Nodes 0  Nodes Add  yourChildNode                        tree ExpandAll                                        con Close                              catch  Exception ex                                MessageBox Show                           ex Message

User · Answer

You can improve that code   private void Form1 Load object sender  EventArgs e                            D  root Project1 A A pdf          D  root Project1 B t pdf          D  root Project2 c pdf                     List lt string gt  n   new List lt string gt             List lt string gt  kn   new List lt string gt             n   Directory GetFiles   D  root           SearchOption AllDirectories  ToList            kn   Directory GetDirectories   D  root           SearchOption AllDirectories  ToList            foreach  var item in kn                        treeView1 Nodes Add item ToString                       for  int i   0  i  lt  treeView1 Nodes Count  i                          n   Directory GetFiles treeView1 Nodes i  Text         SearchOption AllDirectories  ToList                for  int zik   0  zik  lt  n Count  zik                                  treeView1 Nodes i  Nodes Add n zik  ToString

User · Answer

It looks like you are only adding children to the first parent treeView2 Nodes 0  Nodes Add yourChildNode  Depending on how you want it to behave  you need to be explicit about the parent node you wish to add the child to  For Example  from your screenshot  if you wanted to add the child to the second node you would need  treeView2 Nodes 1  Nodes Add yourChildNode  If you want to add the children to the currently selected node  get the TreeView SelectedNode and add the children to it   Try TreeView to get an idea of how the class operates   Unfortunately the msdn documentation is pretty light on the code samples    I m missing a whole lot of safety checks here  Something like  untested    private void addChildNode Click object sender  EventArgs e      TreeNode ParentNode   treeView2 SelectedNode      for ease of debugging    if  ParentNode    null        ParentNode Nodes Add  Name Of Node        treeView2 ExpandAll         so you can see what s been added                   treeView2 Invalidate        requests a redraw

User · Answer

void treeView string    LineString                int line   LineString Length          string AssmMark               string PartMark               TreeNode aNode          TreeNode pNode          for   int i 0   i lt line   i                 string sLine   LineString i               if   sLine StartsWith  ASSEMBLY                       sLine    sLine Replace  ASSEMBLY                        string   aData   sLine Split new char                           AssmMark    aData 0  Trim                      TreeNode aNode                    aNode   new TreeNode AssmMark                   treeView1 Nodes Add AssmMark AssmMark                             if  sLine Trim   StartsWith  PART                       sLine    sLine Replace  PART                        string   pData   sLine Split new char                           PartMark   pData 0  Trim                    pNode   new TreeNode PartMark                   treeView1 Nodes AssmMark  Nodes Add pNode

User · Answer

I needed to do something similar and came across the same issues  I used the AfterSelect event to make sure I wasn t getting the previously selected node   It s actually really easy to reference the correct node to receive the new child node    private void TreeView1 AfterSelect object sender  System Windows Forms TreeViewEventArgs e         show dialogbox to let user name the new node    frmDialogInput f   new frmDialogInput       f ShowDialog           find the node that was selected     TreeNode myNode   TreeView1 SelectedNode        create the new node to add     TreeNode newNode   new TreeNode f EnteredText         add the new child to the selected node     myNode Nodes Add newNode

User · Answer

It s not that bad  but you forgot to call treeView2 EndUpdate   in your addParentNode Click   method  You can also call treeView2 ExpandAll   at the end of your addChildNode Click   method to see your child node directly     private void addParentNode Click object sender  EventArgs e      treeView2 BeginUpdate        treeView2 Nodes Clear      string yourParentNode    yourParentNode   textBox1 Text Trim      treeView2 Nodes Add yourParentNode     treeView2 EndUpdate       private void addChildNode Click object sender  EventArgs e      if  treeView2 SelectedNode    null        string yourChildNode      yourChildNode   textBox1 Text Trim        treeView2 SelectedNode Nodes Add yourChildNode       treeView2 ExpandAll            I don t know if it was a mistake or not but there was 2 TreeViews  I changed it to only 1 TreeView     EDIT  Answer to the additional question  You can declare the variable holding the child node name outside of the if clause   private void addChildNode Click object sender  EventArgs e      var childNode   textBox1 Text Trim      if   string IsNullOrEmpty childNode         TreeNode parentNode   treeView2 SelectedNode    treeView2 Nodes 0       if  parentNode    null          parentNode Nodes Add childNode         treeView2 ExpandAll                  Note  see http   www yoda arachsys com csharp csharp2 nullable html for info about the    operator

User · Answer

Example of adding child nodes   private void AddExampleNodes                         TreeNode node               node   treeView1 Nodes Add  Master node                node Nodes Add  Child node                node Nodes Add  Child node 2                 node   treeView1 Nodes Add  Master node 2                node Nodes Add  mychild                node Nodes Add  mychild

User · Answer

Guys use this code for adding nodes and childnodes for TreeView from C  code     KISS  Keep It Simple  amp  Stupid      protected void Button1 Click object sender  EventArgs e                           TreeNode a1   new TreeNode  Apple             TreeNode b1   new TreeNode  Banana            TreeNode a2   new TreeNode  gree apple            TreeView2 Nodes Add a1           TreeView2 Nodes Add b1           a1 ChildNodes Add a2

User · Answer

You may do as follows to Populate treeView with parent and child node  And also with display and value member of  parent and child nodes      arrayRoot   taskData GetRocordForRoot        iterate through database table     for  int j   0  j  lt arrayRoot length  j                       TreeNode root   new TreeNode        Creating new root node                 root Text    displayString                   root Tag    valueString                   treeView1 Nodes Add root     Adding the root node               arrayChild   taskData GetRocordForChild      iterate through database table                 for  int i   0  i  lt  arrayChild length  i                          TreeNode child   new TreeNode       creating child node                     child Text    displayString                      child Tag    valueString                       root Nodes Add child      adding child node

[c#] adding child nodes in treeview

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