Page_Load if statement fires regardless - asp.net

Is there any reason why an if then statement would fire regardless:
Its inside my Page_load:
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Dim a As New Clicks
If Request.QueryString("u") IsNot Nothing Then
a.Click(Request.QueryString("u"), Request.ServerVariables("REMOTE_ADDR"), Request.ServerVariables("HTTP_USER_AGENT"))
Response.Redirect(urls.GetURL(Request.QueryString("u")))
End If
End Sub
As a result, I am get 126 instances of a.Click per page load when "u" isnt present?
I have tried to move to other Page Events but same result

Created a workaround by encasing if statement in the original if statement to capture the unwanted items.
Not the perfect solution but is working

Related

How To Pass Control As A Variable

This is one of those problems which seems like it should have a simple solution but I can't work out what it is!
How can I pass a control from one sub to another if the first sub doesn't actually call the second? For example, where btnChangeText is in a panel that has a ModalPopupExtender called mpExample, and therefore isn't usually visible:
Protected Sub btnChangeText_Click(sender as object, e as EventArgs) Handles btnChangeText.Click
<SpecifiedTextBox>.Text = "Hello"
End Sub
And then on the main page, visible at all times, is a button associated with each textbox. In this example, it's textbox15:
Protected Sub btnChangeTextBox15_Click(sender as object, e as EventArgs) Handles btnChangeTextBox15.Click
<Set TextBox15 as variable>
mpExample.Show()
End Sub
I know it's a silly example - believe me when I say that the real application I want to make of this actually makes sense! But the point is that I want to somehow store the name of the control to be updated by the first sub when the second sub is run.
If I was calling the first sub from the second it'd be easy, I'd just pass it as an argument, but I'm not. The first sub is called from a button click and is an independent action from the running of the second sub.
I don't seem to be able to use a session variable (my first thought) because I can't find any way to store the control name as a string and then convert it back to an actual control when the first sub runs. That'd be the easiest answer if somebody could tell me how to do it.
One approach would be to store the control's ID as a string in a Session variable, and then use the FindControl method to grab the control in your 2nd Click event.
Protected Sub btnChangeTextBox15_Click(sender as object, e as EventArgs) Handles btnChangeTextBox15.Click
Session("currentTextBox") = TextBox15.ID
mpExample.Show()
End Sub
Protected Sub btnChangeText_Click(sender as object, e as EventArgs) Handles btnChangeText.Click
Dim currentTextBox As TextBox
currentTextBox = CType(Page.FindControl(Session("currentTextBox")),TextBox)
currentTextBox.Text = "Hello"
End Sub
Note that if your TextBox15 control is inside some kind of container (a Panel or something), you'll need to use that container's FindControl method, rather than Page.FindControl.
Another approach is to store the TextBox itself in a Session variable, and then pull that out to set the text in your other method. Note that this only works if the methods are both called in the same request (which doesn't sound like it would work for your use-case). Here's what that would look like:
Protected Sub btnChangeTextBox15_Click(sender as object, e as EventArgs) Handles btnChangeTextBox15.Click
Session("currentTextBox") = TextBox15
mpExample.Show()
End Sub
Protected Sub btnChangeText_Click(sender as object, e as EventArgs) Handles btnChangeText.Click
Dim currentTextBox As TextBox
currentTextBox = CType(Session("currentTextBox"), TextBox)
currentTextBox.Text = "Hello"
End Sub

Having to press an asp.net button twice

I have a button that sets a session variable when clicked. But for some reason, I have to click it twice in order for the save to actually happen. Is there anyway around this?
Thanks
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If CInt(Session("save")) <> 1 Then
'save something ...
End If
End Sub
Private Sub btnSave_Click(sender As Object, e As System.EventArgs) Handles btnSave.Click
Session("save") = 1
End Sub
Page_Load runs before btnSave_Click. You can see more information about the ordering of events in MSDN.
In other words, when btnSave is clicked, the postback runs the Page_Load then the btnSave_Click method. To fix this problem, move the code 'save something ... into the btnSave_Click method.

client side script for treeview events

I have a Treeview with "populateOnDemand" set to true. I want this treeview to keep its state (nodes expanded/collapsed) from one page to another. Viewstate doesn't work because the treeview is different for each page. Here is my code at the moment.
ASPX page :
<asp:TreeView
ID="arbre"
EnableViewState="true"
PopulateNodesFromClient="true"
runat="server" />
Code behind :
Protected Sub arbre_TreeNodeCollapsed(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.TreeNodeEventArgs) Handles arbre.TreeNodeCollapsed
CType(Session("listeNoeudsOuverts"), Hashtable)(e.Node.Value) = True
End Sub
Protected Sub arbre_TreeNodeExpanded(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.TreeNodeEventArgs) Handles arbre.TreeNodeExpanded
CType(Session("listeNoeudsOuverts"), Hashtable)(e.Node.Value) = False
End Sub
Protected Sub arbre_TreeNodePopulate(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.TreeNodeEventArgs) Handles arbre.TreeNodePopulate
// code to populate nodes
CType(Session("listeNoeudsOuverts"), Hashtable)(e.Node.Value) = True
End Sub
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Session("listeNoeudsOuverts") Is Nothing Then
Session("listeNoeudsOuverts") = New Hashtable()
End If
// other stuff
End Sub
This works well, buf I wish I could avoid the postback everytime the user expands or collapses a node. I know I can set EnebleClientScript to true and manage the events client side in Javascript but I won't be able to use my session variable anymore. Is there a way to achieve this ?
Thank you
I will answer myself to a certain extent.
I've done some tests and research, EnableClientScript is true by default, and indeed means that expand and collapse actions are processed client side, by Javascript code that is automaticalt generated by the .Net framework. You can't edit it.
Apparently, if you need to add custom actions when a user expands or collapses anode, you have to use TreeNodeExpanded and TreeNodeCollapsed events, like i did above, and can't avoid postbacks because they are triggered server-side.

DataPager ceases to work when PageSize is set in code

I have a standard ASP.Net DataPager with a standard ListView (using a DataTable as a data source).
When I set PageSize="24" in the design code:
<asp:DataPager runat="server" ID="DataPager1" PagedControlID="ListView1" QueryStringField="page" PageSize="24" >
the paging works as advertised.
However, when I then change that in code, in the Page_Load, eg:
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
DataPager1.PageSize = 48
End Sub
the paging ceases to work completely, while the initial loaded data set is indeed 48 items.
I can't see anything in the code which would affect this, so I'm wondering if I'm missing something - should I be changing something else?
Regards
Moo
Protected Sub DataPager1_Init(ByVal sender As Object, ByVal e As System.EventArgs) Handles DataPager1.Init
DataPager1.PageSize = 48
End Sub
I managed to get this working by setting the page size property in the init event for the datapager.
This sort of error I usually find is a data-binding issue... either binding when you shouldn't, or not re-binding when appropriate. Hard to tell from your little snippet of code.
I am unfamiliar with the DataPager object, but I suspect it must rebind the data when you set the PageSize. If so, then every time the page loads it is re-binding and you are losing events. Have you tried this?
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not IsPostBack
DataPager1.PageSize = 48
End If
End Sub

My Session Value is Not Changing

Partial Class _Default
Inherits System.Web.UI.Page
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If IsPostBack = True Then
Session("x") = "ABC"
End If
End Sub
Protected Sub btnABC_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnABC.Click
Session("x") = "ABC"
End Sub
Protected Sub btnCBA_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnCBA.Click
Session("x") = "CBA"
End Sub
Protected Sub btnShow_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnShow.Click
TextBox1.Text = Session("x")
End Sub
End Class
Three buttons-ABC,CBA and Show.
if you click on ABC and then Click on Show button The textbox shows "ABC"
but when I Clicking on CBA button And then Click on Show button The textbox shows again "ABC". IsPostback property will true on each time the page is posted to the server.
So the session reset the value.
how to overcome this issue ????
If you set the value in page_load(), this assignment occurs every time you load the page. Maybe you want to set this value only at the first call of the page:
If IsPostback = False Then
Session("x") = "Something"
End If
The second load of the page will not overwrite the value you set in button1_click.
When you press the show button it causes a postback to the server. The Page_Load method fires first, and you assign "ABC" into Session("x"). Then you're putting Session("x") into into the textbox.
What you'd probably want is this instead:
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not IsPostBack Then
Session("x") = "ABC"
End If
End Sub
Besides what other people wrote above, I also recommend you to assign Session values during Page_InitComplete event. Because mostly developers work in Page_Load stage and some times assigning Session values as well may throw errors because of it. It is like which one is happening before or after. You can make mistakes and so on.

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