CheckBoxList capture values into Sub Page_Init
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Category: General Discussion
Forum Name: ASP.NET Discussion
Forum Description: Discussion and chat on ASP.NET related topics.
URL: https://forums.webwiz.net/forum_posts.asp?TID=26145
Printed Date: 28 March 2026 at 9:03am
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Topic: CheckBoxList capture values into Sub Page_Init
Posted By: webpaws
Subject: CheckBoxList capture values into Sub Page_Init
Date Posted: 21 August 2008 at 9:05am
I am trying to capture the values of my CheckBoxList items selected, capture the values into a MySQL statement and post into my Sub Page_Init on a re-page or postback to change the SQL statement (data in datalist). I can capture the items, but not preserve them in the sub Page_Init, nor on a repage, I loose the selected items in the checkboxlist.
Here's part of my code:
<p style="font-size:small;">
<asp:Button ID="SubmitProdtype" OnClick="submit_prodtype" runat="server" Text="Show:" style="font-size:small; float:left;" />
<asp:CheckBoxList
ID="CBL_ProductType"
runat="server"
RepeatDirection="Horizontal"
TextAlign="Left"
CellSpacing="3"
style="font-size:small; float:left; padding-right:10px;"
>
<asp:ListItem Value="Wrapper" Text="Standard " />
<asp:ListItem Value="KingSize" Text="KingSize " />
<asp:ListItem Value="HalfPound" Text="HalfPound " />
<asp:ListItem Value="Mini" Text="Mini " />
<asp:ListItem Value="Label" Text="SplashBands " />
<asp:ListItem Value="MyMintos" Text="MyMintos " />
<asp:ListItem Value="Invitation" Text="Cards " />
</asp:CheckBoxList>
</p>
and the VB code behind:
Sub submit_prodtype(ByVal sender As Object, ByVal e As EventArgs)
Dim ckProduct As ListItem
For Each ckProduct In CBL_ProductType.Items
If ckProduct.Selected Then
Dim ProdType As Object = CBL_ProductType.SelectedValue
Dim ckProductVal As Object = ckProduct.Value
prTySQL &= "Product.ProductType = '" & ckProductVal & "' Or "
'Response.Write("init page sub prTySQL = " & prTySQL & "<br>")
'Response.Write("init page sub ckProductVal = " & ckProductVal & "<br>")
End If
Next
Response.Write("submit_prodtype sub prTySQL = " & prTySQL & "<br>")
End Sub
Protected Sub Page_Init(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Init
Dim cnn As New MySqlClient.MySqlConnection(ConfigurationManager.ConnectionStrings("ConnectionStringMySQL").ConnectionString())
Dim strSQL As String = ""
Response.Write("Page_Init sub prTySQL = " & prTySQL & "<br>")
'For Poduct Only Queries
If Request.QueryString("product") <> "" And Request.QueryString("keyword") = "" Then
strProduct = Request.QueryString("product")
strProduct = strProduct.Replace("'", "") 'sql injection prevention
strProduct = strProduct.ToLower
ElseIf Request.QueryString("product") = "" And Request.QueryString("keyword") <> "" Then
If Request.QueryString("keyword").Length = 2 Then
strProduct = Request.QueryString("keyword")
strProduct = strProduct.Replace("'", "") 'sql injection prevention
strProduct = strProduct.ToLower
strSQL &= "SELECT DISTINCT ProductId, Name, LongDescr, ProductType, Size "
strSQL &= "FROM product "
strSQL &= "WHERE ProductId REGEXP '" & strProduct & "' "
strSQL &= "AND (product.Active = 'Y') "
If Session("SiteID") = "100" Then
strSQL &= "AND ( Product.SiteID = '100' ) "
Else
&
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Anyone who has never made a mistake has never tried anything new. - Albert Einstein
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Replies:
Posted By: jamie.townsend
Date Posted: 21 August 2008 at 5:13pm
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Perhaps to perserve placing the code in a if (!isPostBack) {}
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Posted By: webpaws
Date Posted: 21 August 2008 at 6:20pm
I have tried putting the Sub submit_prodtype code in a
IF Not Page.IsPostBack Then
...perform code
End If
But this doesn't get the variable prTySQL to properly post into the Sub Page_Init. Is there a ViewState or Session command to preserve the value of the variable? I also think the Sub Page_Init is occurring prior to the Sub submit_prodtype code and therefor the variable would not be populated yet?
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Anyone who has never made a mistake has never tried anything new. - Albert Einstein
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Posted By: jamie.townsend
Date Posted: 22 August 2008 at 8:02am
Please see here for the page life cycle: http://msdn.microsoft.com/en-us/library/ms178472.aspx - http://msdn.microsoft.com/en-us/library/ms178472.aspx
The Page_Init will fire before anything else including page_load, see the link above for clarification.
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Posted By: webpaws
Date Posted: 27 August 2008 at 6:50pm
I found a solution by putting my code into Page_Load and using a URL Variable if no change occurs in the CheckBoxList to preserve their state. First (if there are state changes in the CheckBoxes, I count them and then re-iterate their condition to the page as it is loading to keep their state on PostBack (CheckBoxList_ID.Items(j).Selected = True). Second, if no change is found, I use a URL variable to determine the last state and keep the correct boxes checked. Another way to do this is with ViewState or Session, but I found this more consistent with the rest of my code.
The VB code behind:
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
'Keeps Search Box text persistent
'Determine which Products are selected to check appropriate checkboxlist listitem
Dim selectedCount As Integer = 0
For i As Integer = 0 To CBL_ProductType.Items.Count - 1
If CBL_ProductType.Items(i).Selected Then
selectedCount += 1
End If
Next
If selectedCount > 0 Then
'Reset Selected Items to All
'CountxFour = 1111111
For j As Integer = CBL_ProductType.Items.Count - 1 To 0 Step -1
If CBL_ProductType.Items(j).Selected = True Then
'CountxFour = CountxFour + CBL_ProductType.Items(j).Value
CBL_ProductType.Items(j).Selected = True
End If
Next j
Else
If Not Request.QueryString("pt") Is Nothing And Request.QueryString("pt") <> "" Then
If Request.QueryString("pt") > 1111111 Then
If IsNumeric(Request.QueryString("pt")) Then
Dim chk As Integer = Request.QueryString("pt")
'CountxFour = 1111111
If Mid(chk, 1, 1) >= 2 Then
CBL_ProductType.Items(0).Selected = True
'CountxFour = CountxFour + CBL_ProductType.Items(0).Value
End If
If Mid(chk, 2, 1) >= 2 Then
CBL_ProductType.Items(1).Selected = True
'CountxFour = CountxFour + CBL_ProductType.Items(1).Value
End If
If Mid(chk, 3, 1) >= 2 Then
CBL_ProductType.Items(2).Selected = True
'CountxFour = CountxFour + CBL_ProductType.Items(2).Value
End If
If Mid(chk, 4, 1) >= 2 Then
CBL_ProductType.Items(3).Selected = True
'CountxFour = CountxFour + CBL_ProductType.Items(3).Value
End If
If Mid(chk, 5, 1) >= 2 Then
CBL_ProductType.Items(4).Selected = True
'CountxFour = CountxFour + CBL_ProductType.Items(4).Value
End If
If Mid(chk, 6, 1) >= 2 Then
CBL_ProductType.Items(5).Selected = True
'CountxFour = CountxFour + CBL_ProductType.Items(5).Value
End If
&nbs
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Anyone who has never made a mistake has never tried anything new. - Albert Einstein
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