【Vegas原创】TreeView操作数据库的使用方法（VB）

最新推荐文章于 2020-12-13 12:24:41 发布

转载最新推荐文章于 2020-12-13 12:24:41 发布 · 193 阅读

文章标签：

#数据库 #ui

本文介绍如何使用 ASP.NET 中的 TreeView 控件，并通过数据库获取数据来动态填充 TreeView 的节点。根据用户角色的不同，展示不同的节点内容。

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     Dim dbAccess As New DBAccess

        Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
            If Not Page.IsPostBack Then
                PopulateNodes(TreeView1.Nodes, 0)

            End If
        End Sub

        Protected Sub TreeView1_TreeNodePopulate(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.TreeNodeEventArgs) Handles TreeView1.TreeNodePopulate

            PopulateNodes(e.Node.ChildNodes, e.Node.Value)

        End Sub

        Public Sub PopulateNodes(ByVal nodes As TreeNodeCollection, Optional ByVal intParentID As Int32 = 0)

            Dim dt As New DataTable()
            dt = GetTreeTable()
            Dim strExpression As String
            strExpression = "[parentID] = " & intParentID
            Dim foundRows() As DataRow
            foundRows = dt.Select(strExpression)

            Dim I As Integer
            For I = 0 To foundRows.GetUpperBound(0)
                Dim tn As New TreeNode()

                tn.Text = foundRows(I).Item("TableName").ToString()
                tn.Value = foundRows(I).Item("ID").ToString()
                tn.NavigateUrl = foundRows(I).Item("url").ToString()
                tn.Target = foundRows(I).Item("target").ToString()
                tn.CollapseAll()
                tn.Expand()

                Dim dr() As DataRow
                dr = dt.Select("[parentID] = " & tn.Value)
                If dr.GetUpperBound(0) > -1 Then
                    tn.PopulateOnDemand = True
                End If
                nodes.Add(tn)
            Next


        End Sub

        Public Function GetTreeTable() As DataTable
            Dim dt As New DataTable()
            Dim ds As New DataSet()
            '''''''''''''''''''''''''TreeView Visible ~~~~~~~~~~~~~~~~~~~~~~@#@!~~~ by Vegas

            Dim cookies As HttpCookie
            cookies = Request.Cookies("PAS")
            Dim workid As String = cookies("Emp_No")
            Dim strPa_Rank As String = cookies("Job_Rank")
            Dim super_user As String = cookies("Super_User")

            If Integer.Parse(strPa_Rank) > 30 Then
                If Integer.Parse(super_user) = 0 Then
                    dt = dbAccess.GetDataTable("select * from treeview where id<>2 and id<>4 order by id")
                    HttpContext.Current.Cache.Insert("Treeview", dt)
                Else
                    dt = dbAccess.GetDataTable("select * from treeview order by id")
                    HttpContext.Current.Cache.Insert("Treeview", dt)
                End If
            Else
                If Integer.Parse(super_user) = 0 Then

                    dt = dbAccess.GetDataTable("select * from treeview where id<>2 order by id")
                    HttpContext.Current.Cache.Insert("Treeview", dt)
                Else
                    dt = dbAccess.GetDataTable("select * from treeview order by id")
                    HttpContext.Current.Cache.Insert("Treeview", dt)
                End If
            End If

            Return dt
        End Function

    End Class

表结构：