Treeview from DataTable

Question

Hi have a data Table with 3 fields and my expected tree view will like this below image.

My data table returns the details like this.

And i tried the below code. Here child node not getting listing properly

 public void BuildTree(DataTable dt, TreeView trv, Boolean expandAll)
    {
        trv.Nodes.Clear();
        TreeNode node = default(TreeNode);
        TreeNode subNode = default(TreeNode);
        foreach (DataRow row in dt.Rows)
        {
            node = Searchnode(row[0].ToString(), trv);
            if (node != null)
            {
                subNode = new TreeNode(row[1].ToString());
                node.Nodes.Add(subNode);
            }
            else
            {
                node = new TreeNode(row[0].ToString());
                subNode = new TreeNode(row[1].ToString());
                node.Nodes.Add(subNode);
                trv.Nodes.Add(node);
            }
        }
        if (expandAll)
        {
            trv.ExpandAll();
        }
    }
    private TreeNode Searchnode(string nodetext, TreeView trv)
    {
        foreach (TreeNode node in trv.Nodes)
        {
            if (node.Text == nodetext)
            {
                return node;
            }
        }
        return null;
    }

Here child node not getting listing properly What do you want the code to do? What does it actually do? — mjwills
– mjwills, Commented Sep 7, 2017 at 12:46
I want to populate the tree view like in the image based on the data table i have. But i am not able to add second child — Jzl
– Jzl, Commented Sep 7, 2017 at 12:59

mnieto · Accepted Answer · 2017-09-07 15:00:37Z

I'm suposing that datatable is previosly ordered by CustomerName, DeliverySchedule, Name

Initialize test data:

    private void InitializeDataTable() {
        dt = new DataTable();
        dt.Columns.Add("DeliverySchedule");
        dt.Columns.Add("Name");
        dt.Columns.Add("CustomerName");

        AddRow("Daily", "Test", "Team Venkat");
        AddRow("Daily", "TestB", "Team Venkat");
        AddRow("Weekly", "OtherName", "Team Venkat");
        AddRow("Weekly", "OtherName2", "Team Venkat");
        AddRow("Daily", "Test", "Team2");
        AddRow("Weekly", "Test", "Team2");

    }

    private void AddRow(string schedule, string name, string customer) {
        DataRow row = dt.NewRow();
        row[0] = schedule;
        row[1] = name;
        row[2] = customer;
        dt.Rows.Add(row);
    }

Load tree from DataTable using a three level loop:

    private void LoadBtn_Click(object sender, EventArgs e) {
        int i = 0;
        treeView1.Nodes.Clear();
        while (i < dt.Rows.Count) {
            DataRow row = dt.Rows[i];
            string customer = row.Field<string>(2);
            TreeNode customerNode = treeView1.Nodes.Add(customer);
            while (i < dt.Rows.Count && row.Field<string>(2) == customer) {
                string schedule = row.Field<string>(0);
                TreeNode scheduleNode = customerNode.Nodes.Add(schedule);
                while (i < dt.Rows.Count && row.Field<string>(2) == customer && schedule == row.Field<string>(0)) {

                    string report = row.Field<string>(1);
                    scheduleNode.Nodes.Add(report);
                    if (++i < dt.Rows.Count)
                        row = dt.Rows[i];
                }
            }
        }
    }

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