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1Maintaining Checkbox State in a Listview Control Pagination ASP.NET
2Protected Sub ListView1_ItemCommand(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.ListViewCommandEventArgs) Handles ListView1.ItemCommand
3
4        Dim myButtonPrint1 As Button = CType(ListView1.FindControl("printButton1"), Button)
5        If e.CommandSource Is myButtonPrint1 Then
6            Dim recordsId As New List(Of String)
7            For Each lvi1 As ListViewItem In ListView1.Items
8                Dim chb1 As CheckBox = IIf(lvi1.FindControl("CheckBoxPrintProvider1") Is Nothing, IIf(lvi1.FindControl("CheckBoxPrintProvider3") Is Nothing, lvi1.FindControl("CheckBoxPrintProvider4"), lvi1.FindControl("CheckBoxPrintProvider3")), lvi1.FindControl("CheckBoxPrintProvider1"))
9
10                If chb1.Checked = True Then
11                    Dim param1 As String
12                    param1 = DirectCast(lvi1.FindControl("lblId1"), Label).Text
13                    recordsId.Add(param1)
14
15                End If
16            Next
17
18            ' Store in session to be pulled out in the Printable Page
19            Session("Records") = recordsId
20            Response.Redirect("PrintableProviderList.aspx")
21        End If
22    End Sub
23
24'Trying to Preserve states
25
26Private ReadOnly Property IDs() As List(Of Integer)
27        ' Create a list of ID's that are selected.  ID's is the primary
28        ' Key for this table
29        Get
30            If Me.ViewState("IDs") Is Nothing Then
31                Me.ViewState("IDs") = New List(Of Integer)()
32            End If
33            Return CType(Me.ViewState("IDs"), List(Of Integer))
34        End Get
35    End Property
36
37
38
39    Protected Sub AddRowstoIDList()
40        ' Loop through all the current items in the Listview
41        For Each lvi As ListViewDataItem In ListView1.Items
42            ' Find the checkbox in each row
43            Dim chkSelect As CheckBox = CType(lvi.FindControl("CheckBoxPrintProvider1"), CheckBox)
44            ' If the checkbox is ticked then add the corresponding ID to our private
45            ' list
46            If (Not (chkSelect) Is Nothing) Then
47                ' Get the ID from the datakeynames property
48                Dim ID As Integer = Convert.ToInt32(ListView1.DataKeys(lvi.DisplayIndex).Value)
49                If (chkSelect.Checked AndAlso Not Me.IDs.Contains(ID)) Then
50                    ' Add the ID to our list
51                    Me.IDs.Add(ID)
52                ElseIf (Not chkSelect.Checked AndAlso Me.IDs.Contains(ID)) Then
53                    ' Not checked - remove the ID from our list
54                    Me.IDs.Remove(ID)
55                End If
56            End If
57        Next
58    End Sub
59
60
61
62    Protected Sub ListView1_PagePropertiesChanging(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.PagePropertiesChangingEventArgs) Handles ListView1.PagePropertiesChanging
63        AddRowstoIDList()
64    End Sub
65
66    Protected Sub ListView1_Sorting(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.ListViewSortEventArgs) Handles ListView1.Sorting
67        AddRowstoIDList()
68    End Sub
69
70
71    Protected Sub ListView1_ItemDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.ListViewItemEventArgs) Handles ListView1.ItemDataBound
72        ' Get each Listview Item on DataBound
73        Dim lvi As ListViewDataItem = e.Item
74        If (lvi.ItemType = ListViewItemType.DataItem) Then
75            ' Find the checkbox in the current row
76            Dim chkSelect As CheckBox = CType(lvi.FindControl("CheckBoxPrintProvider1"), CheckBox)
77            ' Make sure we're referencing the correct control
78            If (Not (chkSelect) Is Nothing) Then
79                ' If the ID exists in our list then check the checkbox
80                Dim ID As Integer = Convert.ToInt32(ListView1.DataKeys(lvi.DisplayIndex).Value)
81                chkSelect.Checked = Me.IDs.Contains(ID)
82            End If
83        End If
84    End Sub