Life In USA

'主架構
    Public Sub BuildTree()

        Dim dst As DataSet = GetTreeViewData() '從資料庫把Table撈出來丟到dst
        Session("Dt") = dst.Tables("eip_power_tree")

        For Each masterRow As DataRow In dst.Tables("eip_power_tree").Rows

            If masterRow("Level0") = True Then 'build Root Node
                Dim masterNode As New TreeNode(masterRow("ID"), masterRow("ID"))
                TreeView1.Nodes.Add(masterNode)
                '呼叫建立子節點的函數
                AddNodes(masterNode, masterRow("ID"))
            End If

        Next
     
    End Sub

    Function AddNodes(ByRef tNode As TreeNode, ByVal PId As Integer) As String
        '******** 遞迴增加樹結構節點 ********
        Try

            '定義DataTable
            Dim Dt As DataTable
            '從Session中取得DataTable
            Dt = Session("Dt")

            '定義DataRow承接DataTable篩選的結果
            Dim rows() As DataRow
            '定義篩選的條件
            Dim filterExpr As String
            filterExpr = "UpLevel_id = '" & PId & "'"
            '資料篩選並把結果傳入Rows
            rows = Dt.Select(filterExpr)

            '如果篩選結果有資料
            If rows.GetUpperBound(0) >= 0 Then
                Dim row As DataRow
                Dim tmpNodeId As Long
                Dim NewNode As TreeNode


                '逐筆取出篩選後資料
                For Each row In rows
                    '和權限table比對
                    If powerDt.Select("power_tree_ID='" & row(0) & "'").Length > 0 Then
                        '放入相關變數中
                        tmpNodeId = row(0)
                 
                        '實體化新節點
                        NewNode = New TreeNode
                        '設定節點各屬性
                        NewNode.Text = IIf(IsDBNull(row(1)), "", row(1))
                        NewNode.Value = IIf(IsDBNull(row(6)), "", row(6))
                        'NewNode.NavigateUrl = tmpsUrl
                        'NewNode.Target = tmpsTarget
                        '將節點加入Tree中
                        tNode.ChildNodes.Add(NewNode)

                        '呼叫遞回取得子節點
                        AddNodes(NewNode, tmpNodeId)
                    End If
                Next
            End If
        Catch ex As Exception
            Throw ex
        End Try
        Return True
    End Function

$(document).ready(function() {
            //Restrict Area
            var hid_rest = document.getElementById("Hid_restrict");
            if (hid_rest.value.length > 0) {
                var strRest = hid_rest.value.split(",");
                for (var key in strRest) {
                    if (strRest[key].length > 0) {
                        $('#allCourse > div').filter('#' + strRest[key]).remove();
                    }
                }
            }
            //Left side value左邊區塊
            var hid1 = document.getElementById("Hidden1");

            if (hid1.value.length > 0) {
                var strL1 = hid1.value.split(",");
                for (var key in strL1) {
                    if (strL1[key].length > 0) {
                        $('#L1').append('

' + getCode(strL1[key]) + '

');
                        //remove div from allCouse
                        $('#allCourse > div').filter('#' + strL1[key]).remove();
                    }
                }
            }
            //Right side value右邊區塊
            var hid2 = document.getElementById("Hidden2");
            
            if (hid2.value.length > 0) {
                var strR1 = hid2.value.split(",");
                for (var key in strR1) {
                    if (strR1[key].length > 0) {
                        $('#R1').append('

' + getCode(strR1[key]) + '

');
                        //remove div from allCouse
                        $('#allCourse > div').filter('#' + strR1[key]).remove();
                    }
                }
            }
           
            
        });

function save() {
        var element_left = $('#L1 > .block');
        var element_right = $('#R1 > .block');
        var val1 = '';
        var val2 = '';
        for (var i = 0; i < element_left.length; i++) {
            val1 += element_left[i].id + ",";
        }
        document.getElementById("Hidden1").value = val1;
        for (var i = 0; i < element_right.length; i++) {
            val2 += element_right[i].id + ",";
        }
        document.getElementById("Hidden2").value = val2;
        __doPostBack('LinkButton1', '');

    }

Protected Sub LinkButton1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles LinkButton1.Click
   '這邊放DB Insert String, 將Hidden1 Hidden2的值存入資料庫
    End Sub

1. 首先加入Jquery和需要用到的Javascript：

$(window).bind('load', function() {
//全選的Button
var headerChk = $(".chkHeader");
//datalist 中的 checkbox
var itemChk = $(".checkItem input");
  headerChk.bind("click", function() {
  itemChk.each(function() { 
                this.checked = true;
                })
       });
  itemChk.bind("click", function() {
         if ($(this).checked == false) {
          //這邊放uncheck
                } 
          });
        });
  //撈使用者勾選的項目並處理
  function SendToSMS() {
            var itemChk = $(".checkItem input[type=checkbox]:checked");
            var SMSstr = '';
            //每個選擇的項目
            itemChk.each(function() {
               
                var LB = $(this).attr('id');
                LB = LB.replace('CheckBox1', 'Label2');
                SMSstr += ',' + document.getElementById(LB).innerText;
            })
            if (SMSstr.length > 0) {alert(SMSstr);} 

        }

2. 然後在.aspx頁面中的Datalist：

• Step1 : 在Visual Studio中將CollectionPager.dll加入.net Framework元件後拉到設計視窗內。在CodeBehide的地方設定Datasource, 因為我是用Sqldatasource, 所以我會先轉成Dataview再丟給CollectionPager :

Sub BindDT(ByVal sqlstr As String)
  SqlDataSource1.SelectCommand = sqlstr
  SqlDataSource1.DataBind()
  ViewState("sqlstr") = sqlstr 
  CollectionPager2.DataSource = CType(SqlDataSource1.Select(New System.Web.UI.DataSourceSelectArguments), Data.DataView)         
  CollectionPager2.BindToControl = DataList1 
  CollectionPager2.Visible = True  
  DataList1.DataSource = CollectionPager2.DataSourcePaged   
  DataList1.DataBind() 
End Sub

• 然後在Page_load的地方去呼叫BindDT:

If IsPostBack = True And ViewState("sqlstr") <> Nothing Then

BindDT(ViewState("sqlstr"))

End If

• OK, 大功告成! 如果需要再DataList上下各放一個Pager, 則再多用一個LITERAL Control複製原來的Pager:
• 前端:

• 後端:

  Protected Overrides Sub Render(ByVal writer As HtmlTextWriter)
          litTopPager.Text = CollectionPager2.RenderedHtml
          MyBase.Render(writer)
  End Sub
  

<asp:datalist &nbsp;repeatdirection="Horizontal" cellpadding="4" id="DataList1" 
repeatcolumns="2" runat="server"></asp:datalist>

If e.Item.ItemType = ListItemType.Item Or e.Item.ItemType = ListItemType.AlternatingItem Then
    Dim sp As New Literal
    sp.Text = "</td><tr><td colspan='2'><div style='page-break-after:always'></div></td></tr><tr><td colspan='2'>"
                If e.Item.ItemIndex = 11 Or e.Item.ItemIndex = 23 Or e.Item.ItemIndex = 35 Then
                    e.Item.Controls.Add(sp)
                End If
 End If

<script language="javascript">
function PrintDataList(StrID) {
  
    var prtContent = document.getElementById(StrID);
    var WinPrint = window.open('', '', 'left=0,top=0,width=800,height=400,toolbar=no,scrollbars=auto,status=0');
    WinPrint.document.write(prtContent.innerHTML);
    WinPrint.document.close();
    WinPrint.focus();
    WinPrint.print();
    WinPrint.close();
   
}
</script>

Introduction

Background

The first thing to understand is that CType and DirectCast are not the same thing. Only CType can convert the underlying object to a new instance of an object of a different type. For example, if you want to turn an integer into a string. Since an Integer doesn't inherit a String, a new instance of a String object must be created in order to store the number as a String. CType can do this, DirectCast cannot. Note: There are other ways to do this too such as the Convert.ToString method or CStr().

Dim MyInt As Integer = 123

Dim MyString1 As String = CType(MyInt, String)

Dim MyString2 As String = DirectCast(MyInt, String) ' This will not work

What DirectCast and CType do have in common is their ability to convert an object to a new type based on inheritance or implementation. For example, if you have a String but it is stored in a variable of type Object, you can use DirectCast or CType to treat that variable as an object of type String because type String inherits type Object. In this case, the underlying data in memory is not actually changing, nor is any processing happening on that data.

Dim MyObject As Object = "Hello World"

Dim MyString1 As String = CType(MyObject, String)

Dim MyString2 As String = DirectCast(MyObject, String) ' This will work

The danger: You MUST know what type you are dealing with before using DirectCast. If you have a variable of type Object and you use DirectCast to treat it as a String, you'd better be sure that variable actually contains a String (or Nothing). If an Integer somehow found its way into that variable an exception will be thrown.

A way to check in code if DirectCast will work is by using the TypeOf operator:

If TypeOf MyObject Is String Then

So, assuming you are doing a conversion based on inheritance or implementation, you have a choice: DirectCast vs. CType. Which is better?

The Answer