defaultvb.aspx.vb

Telerik是很大的第三方软件制造商

Imports System
Imports System.Xml
Imports System.Data
Imports System.Drawing
Imports System.Web
Imports System.Data.OleDb
Imports System.Web.UI.WebControls
Imports System.Web.UI.HtmlControls
Imports Telerik.QuickStart
Imports Telerik.WebControls


'/ <summary>
'/ Summary description for _Default.
'/ </summary>

Namespace Telerik.TreeViewExamplesVBNET.LoadOnDemandSql
    Public Class DefaultVB
        Inherits XhtmlPage
        Protected WithEvents RadTree1 As Telerik.WebControls.RadTreeView
        Protected message As Label


        Private Function GetNodeData(ByVal query As String) As DataSet
            Dim dbCon As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + Server.MapPath("~/TreeView/Data/Nodes.mdb"))
            dbCon.Open()

            Dim adapter As New OleDbDataAdapter(query, dbCon)
            Dim ds As New DataSet()
            adapter.Fill(ds)
            dbCon.Close()

            Return ds
        End Function 'GetNodeData


        Private Sub LoadRootNodes()
            Dim ds As DataSet = GetNodeData("SELECT * FROM Nodes WHERE ParentId IS NULL")
            Dim row As DataRow
            For Each row In ds.Tables(0).Rows
                Dim node As New RadTreeNode()
                node.Text = CStr(row("Text"))
                node.Value = Fix(row("Id")).ToString()
                node.ID = Fix(row("Id")).ToString()
                node.ExpandMode = ExpandMode.ServerSide
                RadTree1.Nodes.Add(node)
            Next row
        End Sub 'LoadRootNodes


        Private Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
            If Not Page.IsPostBack Then
                LoadRootNodes()
            End If
        End Sub 'Page_Load


        Private Sub RadTree1_NodeExpand(ByVal o As Object, ByVal e As Telerik.WebControls.RadTreeNodeEventArgs) Handles RadTree1.NodeExpand
            Dim sql As String = "SELECT" + ControlChars.Cr + ControlChars.Lf + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + "Nodes.Id AS NodeId, Nodes.Text AS NodeText, COUNT(Children.Id) AS HasChildren" + ControlChars.Cr + ControlChars.Lf + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + "FROM " + ControlChars.Cr + ControlChars.Lf + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + "Nodes" + ControlChars.Cr + ControlChars.Lf + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + "LEFT JOIN" + ControlChars.Cr + ControlChars.Lf + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + "Nodes Children" + ControlChars.Cr + ControlChars.Lf + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + "ON" + ControlChars.Cr + ControlChars.Lf + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + "Nodes.Id = Children.ParentId" + ControlChars.Cr + ControlChars.Lf + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + "WHERE" + ControlChars.Cr + ControlChars.Lf + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + "Nodes.ParentId = {0}" + ControlChars.Cr + ControlChars.Lf + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + "GROUP BY" + ControlChars.Cr + ControlChars.Lf + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + "Nodes.Id, Nodes.Text" + ControlChars.Cr + ControlChars.Lf + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab + ControlChars.Tab

            sql = String.Format(sql, e.NodeClicked.ID)
            Dim ds As DataSet = GetNodeData(sql)

            e.NodeClicked.Nodes.Clear()
            Dim row As DataRow
            For Each row In ds.Tables(0).Rows
                Dim node As New RadTreeNode()
                node.Text = CStr(row("NodeText"))
                node.ID = Fix(row("NodeId")).ToString()
                If Fix(row("HasChildren")) > 0 Then
                    node.ExpandMode = ExpandMode.ServerSide
                End If
                e.NodeClicked.Nodes.Add(node)
            Next row

            e.NodeClicked.Expanded = True
        End Sub 'RadTree1_NodeExpand

#Region "Web Form Designer generated code"

        Protected Overrides Sub OnInit(ByVal e As EventArgs)
            InitializeComponent()
            MyBase.OnInit(e)
        End Sub 'OnInit


        '/		Required method for Designer support - do not modify
        '/		the contents of this method with the code editor.
        '/ </summary>
        Private Sub InitializeComponent()
        End Sub 'InitializeComponent

#End Region
    End Class 'DefaultCS
End Namespace