How to expand all folder structure from DB using tree view controls

Gani_tpt 2,106 Reputation points

I am using tree view controls in my web application.

I have all the list of folder in my database.

How to bind all the MS SQL DB details with my controls.

Here, i need some rich UI design in tree view to show client (end user) side.

Pls. help us how to make rich UI design template and binding the data from MS SQL DB..

A set of technologies in the .NET Framework for building web applications and XML web services.
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  1. Albert Kallal 5,221 Reputation points

    Ok, so we will assume you have a simple database table with some folders in it.

    Say, like this:

    User's image

    Ok, so now we need to take above from database, and fill out the tree view.

    of course when a user "expands" the treeview, we will list out files (and or folders) in that folder.

    So, drop in a treeview, say this markup:

        <h3>My Folders</h3>
            <asp:TreeView ID="TreeView1" runat="server" 
                <HoverNodeStyle Font-Underline="True" ForeColor="#6666AA" />
                <NodeStyle Font-Names="Tahoma" Font-Size="12pt" ForeColor="Black"
                    HorizontalPadding="2px" NodeSpacing="0px" VerticalPadding="2px" />
                <ParentNodeStyle Font-Bold="False" />
                <SelectedNodeStyle BackColor="#B5B5B5" Font-Underline="False"
                    HorizontalPadding="0px" VerticalPadding="0px" />

    Ok, so now our code to load from database:

        Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
            If Not IsPostBack Then
            End If
        End Sub
        Sub LoadDBFolders()
            Dim rstFolders As DataTable
            rstFolders = MyRst("SELECT * FROM tblFolders ORDER BY Folder")
            ' add this list of folders to the tree.
            TreeView1.ExpandImageUrl = "~/Content/blueclose2.png"
            TreeView1.CollapseImageUrl = "~/Content/blueopen2.png"
            TreeView1.NoExpandImageUrl = "~/Content/file2.png"
            For Each OneRow As DataRow In rstFolders.Rows
                ' lets ONLY display the folder name, no path, no matter where folder is
                Dim FoldersPath As String() = Split(OneRow("Folder"), "\")
                Dim strTopFolder As String = FoldersPath(FoldersPath.Length - 1)
                Dim child As New TreeNode
                child.Text = strTopFolder  ' we display JUST the top folder name
                child.Value = OneRow("Folder") ' we Store/save full path name
                child.Expanded = False
                child.PopulateOnDemand = True
                'child.ShowCheckBox = False
        End Sub

    So, that loads up the tree view.

    However, now the "more" challenging part. When user clicks on a folder, we need to expand the tree view to the file system.

    So, then this bit of code works quite nice:

    I drop this code right below above code:

        Public Class MyFolder
            Public MyFiles As FileInfo()
            Public MyFolders As DirectoryInfo()
        End Class
        Public Function GetFiles(sRootFolder As String) As MyFolder
            Dim MyDir As New DirectoryInfo(sRootFolder)
            Dim cMyFolder As New MyFolder
            cMyFolder.MyFolders = MyDir.GetDirectories("*.*", SearchOption.TopDirectoryOnly)
            cMyFolder.MyFiles = MyDir.GetFiles("*.*", SearchOption.TopDirectoryOnly)
            Return cMyFolder
        End Function
        Protected Sub TreeView1_TreeNodeExpanded(sender As Object, e As TreeNodeEventArgs)
            ' user clicked on tree node, get the folder, and fill out files
            ' and sub folders too!!!
            Dim child As TreeNode = e.Node
            Dim dtChild As MyFolder = GetFiles(child.Value) ' get ALL files + folders
            LoadTreeFiles(child.Value, dtChild, child)
        End Sub
        Sub LoadTreeFiles(fRootL As String,
                          lParent As MyFolder,
                          tTreeNode As TreeNode)
            ' add folders if any
            For Each sFolder As DirectoryInfo In lParent.MyFolders
                Dim child As New TreeNode
                child.Text = sFolder.Name
                child.Value = sFolder.FullName
                child.Expanded = False
                child.PopulateOnDemand = True
                child.ShowCheckBox = False
            ' now any files
            For Each sFile As FileInfo In lParent.MyFiles
                Dim child2 As New TreeNode
                child2.Text = sFile.Name
                child2.Value = sFile.FullName
                child2.Expanded = False
                child2.ShowCheckBox = True
                child2.PopulateOnDemand = False
        End Sub

    And the result is now this:


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  2. Lan Huang-MSFT 28,121 Reputation points Microsoft Vendor

    Hi @Gani_tpt,

    You didn't provide your database data, I wrote you an example with test data.

    The PopulateTreeView method is a recursive function. Inside the Page Load event, the TreeView is populated with the records from the parent table.

    Inside the PopulateTreeView method, a loop is executed over the DataTable and if the ParentId is 0 i.e. the node is a parent node, a query is executed over the child table to populate the corresponding child nodes and again the PopulateTreeView method is called.

    This process continues until all parent nodes along with their child nodes are added to the TreeView.

     <form id="form1" runat="server">    
            <asp:TreeView ID="TreeView1" runat="server" ImageSet="XPFileExplorer" NodeIndent="15">
                <HoverNodeStyle Font-Underline="True" ForeColor="#6666AA" />
                <NodeStyle Font-Names="Tahoma" Font-Size="8pt" ForeColor="Black" HorizontalPadding="2px"
                    NodeSpacing="0px" VerticalPadding="2px"></NodeStyle>
                <ParentNodeStyle Font-Bold="False" />
                <SelectedNodeStyle BackColor="#B5B5B5" Font-Underline="False" HorizontalPadding="0px"
                    VerticalPadding="0px" />
    protected void Page_Load(object sender, EventArgs e)
                if (!this.IsPostBack)
                    DataTable dt = this.GetData("SELECT Id, Name FROM parent");
                    this.PopulateTreeView(dt, 0, null);
            private void PopulateTreeView(DataTable dtParent, int parentId, TreeNode treeNode)
                foreach (DataRow row in dtParent.Rows)
                    TreeNode child = new TreeNode
                        Text = row["Name"].ToString(),
                        Value = row["Id"].ToString()
                    if (parentId == 0)
                        DataTable dtChild = this.GetData("SELECT Id, Name FROM child WHERE ParentId = " + child.Value);
                        PopulateTreeView(dtChild, int.Parse(child.Value), child);
            private DataTable GetData(string query)
                DataTable dt = new DataTable();
                string constr = ConfigurationManager.ConnectionStrings["DBCS"].ConnectionString;
                using (SqlConnection con = new SqlConnection(constr))
                    using (SqlCommand cmd = new SqlCommand(query))
                        using (SqlDataAdapter sda = new SqlDataAdapter())
                            cmd.CommandType = CommandType.Text;
                            cmd.Connection = con;
                            sda.SelectCommand = cmd;
                    return dt;
    CREATE TABLE [dbo].[parent ]
        [Name] NVARCHAR(50) NULL
    CREATE TABLE [dbo].[child]
        [Name] NVARCHAR(50) NULL, 
        [ParentId] INT NULL

    User's image

    Best regards,
    Lan Huang

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