I have an issue very similar to this question. There is a dropdown on my page that causes a postback, during which the ImageUrl property of an ASP:Image is changed. When that postback happens, any value that is in the FileUpload is cleared. That's the problem I'm trying to solve, but I ran into this issue in the process.
I'm trying to solve the problem by wrapping the dropdown and image in an UpdatePanel. Here is my ASP markup:
<asp:UpdatePanel ID="upPanel" runat="server">
<Triggers>
<asp:AsyncPostBackTrigger ControlID="myDropdown"
EventName="SelectedIndexChanged" />
</Triggers>
<ContentTemplate>
<tr valign="top">
<td>Tag:</td>
<td>
<asp:DropDownList ID="myDropdown" runat="server"
AppendDataBoundItems="true" DataTextField="Name"
DataValueField="ID" AutoPostBack="true">
<asp:ListItem Value="" />
</asp:DropDownList>
</td>
</tr>
<TR vAlign="top">
<TD width="150">Thumbnail:</TD>
<TD>
<asp:Image id="imgThumbnail" Runat="server"
AlternateText="No Image Found"
Visible="false"></asp:Image><BR>
</TD>
</TR>
</ContentTemplate>
</asp:UpdatePanel>
EDIT: my code-behind doing the update is here:
Private Sub myDropdown_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs) Handles myDropdown.SelectedIndexChanged
If (myDropdown.SelectedValue <> "-1") Then
imgThumbnail.ImageUrl = Application("AppPath") + "/Modules/Broadcaster/ImageGen.ashx?tag=" + myDropdown.SelectedValue
Else
imgThumbnail.ImageUrl = Application("AppPath") + "/Modules/Broadcaster/ImageGen.ashx?defaultTag=" + _modID.ToString()
End If
End Sub
I can see the async postback happening in FireBug, but the image URL does not change. What am I doing wrong?
You're missing the code that's doing the update (the code that is called by the selected index changing within the dropdown); however, I'm going to venture a guess that your problem is being caused because you are loading the DDL through a control instead of programmatically.
The reason you may be running into this issue is because the page load function is called before the datasource controls are populated, which means that the DDL is not populated by the time you are looking for a value, thus your image is coming up with a blank.
Example:
Dim sTemp As String = "images/myimagenumber" & myDropdown.SelectedIndex & ".jpg"
This will return "images/myimagenumber.jpg" as the value of the sTemp string because there is no value or index selected the the moment the page loads.
I suggest you load the values of the dropdownlist manually (programmatically) and then in the page_load subroutine make sure that it's only repopulating the dropdown when the page loads for the first time.
VB.Net Example:
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)
If Page.IsPostback = False Then
runDBLFillSubHere()
End If
'Run Rest of Code Here'
Sub
I've run into this a couple times over the years and it always ends up being because the DDL isn't populated before I am accessing it.
Related
I have a table that has a loading gif inside of it, that starts with the visible property set to false. I also have a drop down list that has a selection change event that will update information on the page depending on what the user selects. What I want to happen is the loading table to become visible at the beginning of the selection change event, the processing of new information with the selection made by the user to occur, then the loading table to go back to being invisible.
Here is what some of my code looks like:
<asp:UpdatePanel ID="UpdatePanel2" runat="server">
<ContentTemplate>
<table id="tblLoading" runat="server" align="center" width="100%" visible="false">
<tr>
<td align="center">
<img src="../images/Loading_Gif.gif" class="auto-style1" alt="Load" />
</td>
</tr>
<tr align="center">
<td>
<asp:Label runat="server" Font-Names="Tahoma" Font-Size="Larger" Font-Bold="True">Loading...</asp:Label>
</td>
</tr>
</table>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="ddlPayrollPeriodReport" EventName="SelectedIndexChanged"/>
</Triggers>
</asp:UpdatePanel>
<asp:DropDownList ID="ddlPayrollPeriodReport" runat="server" AutoPostBack="True" Font-Size="Large" Font-Names="Tahoma"></asp:DropDownList>
Private Sub ddlPayPeriodReport_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ddlPayrollPeriodReport.SelectedIndexChanged
'set up the link to the HR system
Me.tblLoading.Visible = True
Dim datStart As Date = CDate(Me.ddlPayrollPeriodReport.SelectedItem.Value)
SetUptblReport(datStart)
Me.tblLoading.Visible = False
End Sub
I found out that I need to place the loading table in an UpdatePanel in order for it to change the value of the visible property. However, I noticed that the table will become visible if I don't have the call that turns it invisible. If I have both calls, then both calls are ignored. I am still new to ASP, so is there something I need to know in order to get this to work the way I want it to work?
The changes made in code-behind become visible only after the postback has completed and the page (or the UpdatePanel) has been refreshed. In your case, the page will show the last change that you made to tblLoading in the SelectedIndexChanged event handler, which is to set visible="False". In other words, it was not visible before the postback, and it is still not visible after it.
To show the loading message, you must make the table visible in client code, before the postback is triggered. In order to do that, the table has to be present in the page. The visible="false" setting does not work well for that because it causes ASP.NET to remove the control from the HTML ouptut. You can hide the table with the display: none style property:
<table id="tblLoading" runat="server" align="center" width="100%" style="display: none;">
To make the table visible before the postback, you can process the DropDownList selection change on the client side:
<asp:DropDownList ID="ddlPayrollPeriodReport" ... onchange="showLoadingMessage();">
The Javascript function could be defined as follows:
<script type="text/javascript">
function showLoadingMessage() {
document.getElementById('<%= tblLoading.ClientID %>').style.display = '';
}
</script>
Note: the <% ... %> syntax ensures that any modification to the ID of the control made by ASP.NET is taken into account.
Finally, you can hide the table in your event handler on the server side:
Private Sub ddlPayPeriodReport_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ddlPayrollPeriodReport.SelectedIndexChanged
...
tblLoading.Style("display") = "none"
End Sub
I've searched high and low, I can't seem to find out what's happening with this. I've simplified the code, but I really have taken it back to as basic as this and still have the same problem.
I have a drop down list in a a repeater (in a Web Form with master page):
<asp:DropDownList ID="TicketQuantityDDL" runat="server" CssClass="qtyddl" AutoPostBack="true" OnSelectedIndexChanged="TicketQuantityDDL_SelectedIndexChanged" CausesValidation="false" SelectedIndex='<%# CInt(Eval("Quantity")) - 1%>'>
<asp:ListItem Value="1">1</asp:ListItem>
<asp:ListItem Value="2">2</asp:ListItem>
<asp:ListItem Value="3">3</asp:ListItem>
<asp:ListItem Value="4">4</asp:ListItem>
<asp:ListItem Value="5">5</asp:ListItem>
<asp:ListItem Value="6">6</asp:ListItem>
</asp:DropDownList>
Handler
Protected Sub TicketQuantityDDL_SelectedIndexChanged(sender As Object, e As EventArgs)
myLiteral.text = "Selected Index Changed handled..."
End Sub
The first time the page is loaded if I change the DDL the the page is posted back - the selected index change handler is NOT fired (I've stepped through the code, page.ispostback is true). Every time after the handler works unless the page is full reloaded.
Things I've tried:
Manually adding a handler OnItemCreated
Manually adding a handler OnItemDataBound
Manually registering the control for async postback with scriptmanager
Using OnClientSelectedIndexChanged to trigger postback from the client
Removing AutoPostBack and all of the above again...
I've used Page.Request.Params("__EVENTTARGET") to verify that when the partial postback is fired that the control is the drop down.
Even though viewstate is enabled I've tried specifying this for the control and the page directly.
Disabling validation.
I've tried not binding the value of the drop down and just leaving it
as is with no selected value and then manually setting the initial
selected value - no dice.
Tried removing update panel, same issue.
Things that are DEFINITELY not happening here.
I'm not rebinding on post back if not page.ispostback... databind...
I'm not selecting the same value/first item in the drop down
This isn't an auto ID problem, the controls ID stay the same through postbacks.
I'm not doing anything funky other than binding the repeater to a list of objects.
Why isn't the handler firing the first time? After the first time everything works exactly as intended.
Update
I've replicated the exact same behaviour in a list view. Due to time constraints I've used another approach but I'd really like to know how to fix this or at least know why it doesn't work.
Update 2
I've tested the functionality with a bog standard web form and it functions correctly. Something is up with this being in a contentplaceholder from a masterpage, the script manager or update panel. It's as if the event handler for the dropdown is only registered after the first post back, I've tried registering the handler in DataBound and also in the page LoadComplete events, the same thing still happens.
Update 3
I've since changed it to a list view, I'm having the exact same issue though.
This is on a web form with master page, the master page contains the script manager, the list view is in an update panel, although I've tried removing this and I still have the same issue. I've not included the onselectedindexchanged code, I've made it as simple as changing the text of a literal - doesn't work first post back, does the second.
I had originally specified the list items manually but have changed this to programatically at itemDataBound, still no difference.
As I stated above when I check which control caused the postback it's definitely the ddl, it just doesn't fire selectindexchanged the first time. I've also tried specifying the OnSelectedIndexChange in the control itself, still no dice.
Page load ,bind, list view and on item created code.
Page Load
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not Page.IsPostBack Then
Dim _Basket = SessionHandler.getSessionObject(SessionHandler.SessionObjects.Basket)
If _Basket Is Nothing OrElse DirectCast(_Basket, BasketContainer).BasketItemList.Count = 0 Then
BasketSectionContainer.Visible = False
alertLiteral.Text = AlertGenerator.GetAlertHTML("No Items in Basket", "There are no items in your basket, please use the menu above to navigate the site.", AlertGenerator.AlertType.warning)
If _Basket IsNot Nothing Then SessionHandler.removeSessionObject(SessionHandler.SessionObjects.Basket)
Exit Sub
Else
Dim lBasket = DirectCast(_Basket, BasketContainer)
BindBasket(lBasket)
End If
End If
End Sub
Bind
Private Sub BindBasket(lBasket As BasketContainer)
basketListView.DataSource = lBasket.BasketItems
basketListView.DataBind()
bindTotals(lBasket) 'This just sets text of literals on the page outside of the listview
If lBasket.Postage Then
PostageDDL.visible = True 'This is outside of the list view also
End If
End Sub
Item Created
Private Sub basketListView_ItemCreated(sender As Object, e As ListViewItemEventArgs) Handles basketListView.ItemCreated
Dim QtyDDL As DropDownList = DirectCast(e.Item.FindControl("TicketQuantityDDL"), DropDownList)
AddHandler QtyDDL.SelectedIndexChanged, AddressOf TicketQuantityDDL_SelectedIndexChanged
End Sub
_Item Data Bound _
Private Sub basketListView_ItemDataBound(sender As Object, e As ListViewItemEventArgs) Handles basketListView.ItemDataBound
Dim data As BasketItem = DirectCast(e.Item.DataItem, BasketItem)
Dim QtyDDL As DropDownList = DirectCast(e.Item.FindControl("TicketQuantityDDL"), DropDownList)
For i As Integer = 1 To 6
QtyDDL.Items.Add(New ListItem(i.ToString, i.ToString))
Next
QtyDDL.DataTextField = data.BasketItemID.ToString 'no command arg for DDL so using this, I've tested without, doesn't make a difference.
Select Case data.BasketType
Case BasketInfo.BasketItemType.DiscountedTickets, BasketInfo.BasketItemType.Tickets, BasketInfo.BasketItemType.Goods
'tickets and goods...
QtyDDL.Items.FindByValue(data.Quantity.ToString).Selected = True
Case Else
'non ticket or goods type, disable quantity selection
QtyDDL.Items.FindByValue("1").Selected = True
QtyDDL.Enabled = False
End Select
End Sub
_List View _
<asp:ListView ID="basketListView" runat="server">
<LayoutTemplate>
<table class="cart-table responsive-table">
<tr>
<th>Item</th>
<th>Description</th>
<th>Price</th>
<th>Quantity</th>
<th>Total</th>
<th></th>
</tr>
<asp:PlaceHolder ID="itemPlaceholder" runat="server" />
</table>
<table class="cart-table bottom">
<tr>
<th>
<asp:Button ID="ApplyDiscountCodeButton" runat="server" CssClass="button color pull-right" Text="Apply Code" />
<asp:TextBox ID="DiscountCodeTextBox" runat="server" CssClass="discount-tb pull-right" />
</th>
</tr>
</table>
<div class="clearfix"></div>
</LayoutTemplate>
<ItemTemplate>
<tr>
<td>
<img src="/images/shows/<%# Eval("imageURL")%>.jpg" alt="<%#Eval("BasketItemTitle")%>" class="basketimg" /></td>
<td class="cart-title">
<%#Eval("BasketItemTitle")%>
<br />
<%# String.Format("{0:dddd} {1} {0:MMMM yyyy} | {0:HH:mm}", Eval("PerformanceStarts"), Eval("OrdinalDay"))%>
<br />
<%# Eval("VenueTitle")%>
</td>
<td>
<%#Eval("PriceBandType")%>
<br />
# <%# String.Format("{0:c}", Eval("PriceBandValue"))%>
</td>
<td>
<asp:DropDownList ID="TicketQuantityDDL" runat="server" CssClass="qtyddl" AutoPostBack="true" ClientIDMode="Static" />
</td>
<td class="cart-total"><%#String.Format("{0:c}", Eval("BasketItemTotalValue"))%></td>
<td>
<asp:LinkButton ID="RemoveLinkBtn" runat="server" CssClass="cart-remove" CommandName="RemoveBasketItem" CommandArgument='<%#Eval("BasketItemID")%>' />
</td>
</tr>
</ItemTemplate>
</asp:ListView>
Since the Dropdown in inside the repeater, you can try the following Option instead.
Add OnItemCommand to the repeater. This should definitely Trigger the Event on selection Change in the Dropdown. Then in the OnItemCommand you Need to cast the Sender to DropDownList to be able get the selected value of the dropdown
You have to register the dropdown list event like this.
protected virtual void OnRepeaterItemCreated(object sender, RepeaterItemEventArgs e)
{
DropDownList dropdown = (DropDownList)e.Item.FindControl("TicketQuantityDDL");
dropdown.SelectedIndexChanged += TicketQuantityDDL_SelectedIndexChanged;
}
And also add this piece of code in your repeater.
OnItemCreated="OnRepeaterItemCreated"
And then you can do the selected index changed event like this.
protected void TicketQuantityDDL_SelectedIndexChanged(object sender, EventArgs e)
{
DropDownList mydropdownlist = (DropDownList)sender;
Response.Write(mydropdownlist.SelectedValue);
}
protected void dropdownlist1_SelectedIndexChanged(object sender, EventArgs e)
{
DropDownList ddlListFind = (DropDownList)sender;
ListViewItem item1 = (ListViewItem)ddlListFind.NamingContainer;
DropDownList getDDLList = (DropDownList)item1.FindControl("dropdownlist1");
Label lblMessage = (Label)item1.FindControl("lblMsg");
lblMessage.Visible = true; lblMessage.Text = "dropDown text is : " + getDDLList.SelectedItem.Text + " and value is : " + getDDLList.SelectedItem.Value;
}
I'm having some trouble getting a command link in a gridview to maintain it's ability to change tabs after the initial postback. So below you will see the structure of my content (heavily simplified):
<ajaxToolkit:TabContainer runat="server" ID="tabBody">
<ajaxToolkit:TabPanel runat="server" ID="tabPanel1">
<ContentTemplate>
<asp:UpdatePanel runat="server" ID="updPanel1">
<ContentTemplate>
<asp:Gridview runat="server" ID="grd1" OnRowCommand="grd1_RowCommand" OnRowDataBound="grd1_RowDataBound">
<asp:TemplateField>
<ItemTemplate>
<asp:LinkButton ID="lnkChangePanels" runat="server" CommandArgument='<%#Eval("id") %>' CommandName="gotopanel2" Text='<%#Eval("FirstName") & " " & Eval("LastName")%>' />
</ItemTemplate>
</asp:TemplateField>
</asp:Gridview>
</ContentTemplate>
</asp:UpdatePanel>
</ContentTemplate>
</ajaxToolkit:TabPanel>
<ajaxToolkit:TabPanel runat="server" ID="tabPanel2">
<ContentTemplate>
<asp:UpdatePanel runat="server" ID="updPanel2">
<ContentTemplate>
<asp:Gridview runat="server" ID="grd2">
</asp:Gridview>
</ContentTemplate>
</asp:UpdatePanel>
</ContentTemplate>
</ajaxToolkit:TabPanel>
</ajaxToolkit:TabContainer>
In order to fill the gridview on panel 1, there is a search box which the user types into and I call a function to bind a linq query to it.
Now I add the rowcommand as a postback trigger on rowdatabound:
Protected Sub grd1_RowDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewRowEventArgs)
If e.Row.RowType = DataControlRowType.DataRow Then
Dim lb As LinkButton = CType(e.Row.FindControl("lnkChangePanels"), LinkButton)
If Not lb Is Nothing Then
ToolkitScriptManager1.RegisterPostBackControl(lb)
End If
End If
End Sub
Then here is the code I have to trigger the tab panel to change (and do some other stuff):
Protected Sub grd1_RowCommand(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewCommandEventArgs) Handles grd1.RowCommand
Dim id = e.CommandArgument.ToString()
Select Case e.CommandName
Case "gotopanel2"
eventDetails(id, "C")
tabBody.ActiveTab = tabPanel2
End Select
End Sub
This causes a proper postback and changes the tab, everything works as intended. But if I go back to the first tab and try clicking another row in gridview 1, nothing happens.
Is there a way to structure this so the that either the tab can change without losing the postback trigger or am I going about this all wrong?
Thanks.
Postback trigger is not lost. Problem is caused by individual UpdatePanels in each tab.
Put entire TabContainer within UpdatePanel and you can remove UpdatePanels from tabs (but you don't have to). Make sure that UpdateMode of that new panel is set to "Always".
I think the reason why it does not change in your example is that UpdatePanel only refreshes it's own content and attribute that decides if tab is visible or not is set for div (tabPanel) outside that UpdatePanel. When you go back to tab with grid you do it client-side by clicking on it and that's when it goes wrong.
To get to the bottom of the problem and figure out why it does work during the first postback you would probably have to debug ajax toolkit javascript for TabContainer control.
I have a linkbutton displaying the path of an uploaded document..The tag structure is like so
<tr>
<td>
<asp:Label ID="lblDoc" runat="server" Text="Document:"></asp:Label>
</td>
<td colspan="3">
<asp:LinkButton ID="lnkDoc" runat="server" PostBackUrl="~/Transfer.aspx"></asp:LinkButton>
</td>
</tr>
I am handling the onclick event on the server side:
Private Sub lnkDoc_Click(sender As Object, e As System.EventArgs) Handles lnkDoc.Click
ClientScript.RegisterStartupScript(Me.GetType(), "onclick", "<script language=javascript>window.open('OpenDocument.aspx?DocumentPath=" & System.Web.HttpUtility.UrlEncode(lnkDoc.Text) & "', 'OpenUploadedDoc','left=0px,top=0px,width='+screen.availWidth+',height='+screen.availHeight+',menubar=yes,resizable=yes,scrollbars=1')</script>")
End Sub
But I am not able to click the document path. When I hover over the linkbutton, nothing happens. What could be the issue?
EDIT:
When I try to add onclick on the client side, I get the following error.
Transfer.Private Sub lnkDoc_Click(sender As Object, e As System.EventArgs)' is not accessible in this context because it is 'Private'.
I think there are some validation on your page so click event is not fire so please set causesvalidation="false" of LinkButton as below code and check again:
<asp:LinkButton ID="lnkDoc" causesvalidation="false" runat="server" PostBackUrl="~/Transfer.aspx"></asp:LinkButton
Thanks,
Hitesh
I have fixed the issue. The problem was with rendering the linkbutton in HTML(which was inside a panel). So I placed it in a outside the Panel.
</asp:Panel>
<div>
<asp:Label ID="lblDoc" style="margin-left: 3px" Text="Document: " runat="server"></asp:Label>
<asp:LinkButton ID="lnkDoc" style="margin-left:100px" runat="server" PostBackUrl="~/Transfer.aspx"></asp:LinkButton>
</div>
Thanks all for your suggestions..!
ASPX
<tr>
<td>
<asp:Label ID="lblDoc" runat="server" Text="Document:"></asp:Label>
</td>
<td colspan="3">
<asp:LinkButton ID="lnkDoc" CausesValidation="false" runat="server" Text="Test"></asp:LinkButton>
</td>
</tr>
Code behind
Private Sub lnkDoc_Click(sender As Object, e As System.EventArgs) Handles lnkDoc.Click
ClientScript.RegisterStartupScript(Me.GetType(), "onclick", "<script language=javascript>alert('hi')</script>")
End Sub
try to give onclick event on .aspx page, and check it..
i hope that way it will work
Protected Sub lnkDoc_Click(sender As Object, e As System.EventArgs) Handles lnkDoc.Click
ClientScript.RegisterStartupScript(Me.GetType(), "onclick", "<script language=javascript>window.open('OpenDocument.aspx?DocumentPath=" & System.Web.HttpUtility.UrlEncode(lnkDoc.Text) & "', 'OpenUploadedDoc','left=0px,top=0px,width='+screen.availWidth+',height='+screen.availHeight+',menubar=yes,resizable=yes,scrollbars=1')</script>")
End Sub
Note: make your event Protected not Private
And also You need to add the click event to link button.
<asp:LinkButton ID="lnkDoc" runat="server" PostBackUrl="~/Transfer.aspx" onclick="lnkDoc_Click"></asp:linkbutton>
Add text to the button and make the handler public.
You need to add the click event to link button.
<asp:LinkButton ID="lnkDoc" runat="server" onclick="lnkDoc_Click"></asp:linkbutton>
Page behind file you have to write
Protected Sub lnkDoc_Click((ByVal sender As Object, ByVal e As System.EventArgs) Handles lnkDoc.Click
// code you want to run
End Sub
Maybe you want to set LinkButton.OnClientClick property? It let's you specify client-side handler for rendered link button control.
Take a look:
<asp:linkbutton id="LinkButton1" text="Open Web site" onclientclick="Navigate()" onclick="LinkButton1_Click" runat=Server />
Here Navigate() is a JavaScript function called upon click, and LinkButton1_Click is a server side event handler.
You want to open a new browser window to display a document when user clicks a link, right?
So a better approach will be to create JavaScript function with documentPath parameter (set on the server-side). No need to for messy RegisterStartupScript. You seem to run in circles now. Take a step back and rethink what you really want your code to do.
Warning! This problem is not for the feint of heart. I've spent several days in all trying to troubleshoot it.
I have a Wizard control with about 5 steps, each with several controls ranging from very simple to very complex such as custom jQuery combo boxes based on DropDownLists and TextBoxes. Each step has several of the controls wrapped in a PlaceHolder control.
The Wizard along with all PlaceHolders and their child Controls are nested inside of a View of a MultiView. On the same page I have another View styled like a Form, but not one. This view has corresponding PlaceHolders for each of PlaceHolders within each step of the Wizard.
Depending on the ReferralUrl I call the following function to "Toggle" the view from the Wizard to the form style view by moving all the controls, then setting the active view as follows:
Protected Sub ToggleView() Handles ViewToggle.Click
If Wizard_mv.ActiveViewIndex = 0 Then
ViewToggle.Text = "Toggle Wizard View"
fPH1.Controls.Add(wPH1)
fPH2.Controls.Add(wPH2)
fPH3.Controls.Add(wPH3)
fPH4.Controls.Add(wPH4)
fPH5.Controls.Add(wPH5)
Wizard_mv.ActiveViewIndex = 1
ElseIf Wizard_mv.ActiveViewIndex = 1 Then
ViewToggle.Text = "Toggle Form View"
wPH1.Controls.Add(fPH1)
wPH2.Controls.Add(fPH2)
wPH3.Controls.Add(fPH3)
wPH4.Controls.Add(fPH4)
wPH5.Controls.Add(fPH5)
Wizard_mv.ActiveViewIndex = 0
End If
End Sub
Immediately after this, I use another function for pre-filling the controls with values from a record in a database. After allowing the users to make some changes, they may resubmit the updated record to the database. The problem is that this works just fine if I do so from the Wizard but not after toggling. The trace shows that the Control Tree is empty at the time of submitting the updated record, and hence I cannot grab the user-entered/pre-filled values from this view. The pre-filling works great and the "Selected" values are all correct. The problem arises on the PostBack after clicking submit and it loses all the values and controls.
Please do not answer unless you fully understand my problem and are willing to help. I think the problem very well lies within the page lifecycle. Mysteriously, when I submit from my Wizard, on the postback in Page_Init I get my control values loaded, however when I submit from my form view, neither the controls nor their values are loaded. From what I read, this is an issue of persistence. Really hoping there's a relatively easy solution for this.
Here's a sample of my markup in my Wizard (all styling removed for brevity):
<asp:WizardStep ID="WizardStep1" runat="server" Title="Product Info">
<asp:PlaceHolder ID="wPH1" runat="server" ViewStateMode="Enabled">
<asp:Table ID="ProductInfoTable" runat="server" Width="100%">
<asp:TableHeaderRow>
<asp:TableHeaderCell><h3>Product Line</h3></asp:TableHeaderCell>
<asp:TableHeaderCell><h3>Publication Type</h3></asp:TableHeaderCell>
<asp:TableHeaderCell><h3>Request Type</h3></asp:TableHeaderCell>
</asp:TableHeaderRow>
<asp:TableRow>
<asp:TableCell>
<div class="ui-widget">
<!-- Autocomplete Combobox -->
<asp:DropDownList ID="productLine_ddl" runat="server" DataSourceID="productLineSDS" ViewStateMode="Enabled" DataTextField="Product" DataValueField="ID"></asp:DropDownList>
<asp:TextBox ID="productLine_cb" runat="server" EnableViewState="True"></asp:TextBox>
<button id="productLine_btn" type="button" title="Show All Items"></button>
</div>
</asp:TableCell>
<asp:TableCell>
<asp:DropDownList ID="docType_ddl" runat="server" DataSourceID="docTypeSDS" DataTextField="DocType" DataValueField="ID"></asp:DropDownList>
</asp:TableCell>
<asp:TableCell>
<asp:DropDownList ID="requestType_ddl" runat="server" DataSourceID="requestTypeSDS" DataTextField="RequestType" DataValueField="ID"></asp:DropDownList>
</asp:TableCell>
</asp:TableRow>
<asp:TableRow>
<asp:TableCell ColumnSpan="2">
<asp:MultiView ID="Attachment_mv" runat="server" ActiveViewIndex="0">
<!-- File Upload/Browsing Display -->
<asp:View ID="AttachmentUploadView" runat="server">
<h3 class="inlineH">Attach File: </h3>
<asp:FileUpload ID="AttachmentFile_btn" runat="server" />
<asp:Button ID="UploadFile_btn" runat="server" Text="Upload File" />
</asp:View>
<!-- File Attached Display -->
<asp:View ID="FileAttachedView" runat="server">
<h3 class="inlineH">Uploaded File: </h3>
<asp:Label ID="FileAttachedLabel" runat="server" Text="Label"></asp:Label>
<asp:Literal ID="FilesOnServer" runat="server" />
</asp:View>
</asp:MultiView>
</asp:TableCell>
</asp:TableRow>
</asp:Table>
</asp:PlaceHolder>
</asp:WizardStep>
My Page Lifecycle Events, as requested (in chronological order for your convenience) :)
Dim referrerPage As String
'Initialize Dynamic controls here. These are controls that need to be prefilled, etc.
Private Sub Page_Init(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Init
'DO NOT PREFILL at this stage, as the Controls are not yet rendered and will cause errors.
' Use this section for detecting the "referrerPage" and missing "id" parameters when expected, etc.
If Not IsPostBack Then
ViewState.Clear()
End If
Try
referrerPage = Right(Request.UrlReferrer.AbsolutePath, Len(Request.UrlReferrer.AbsolutePath) - Request.UrlReferrer.AbsolutePath.LastIndexOf("/"c) - 1)
Catch ex As Exception
If Not String.IsNullOrEmpty(Session.Item("referrerPage")) Then
referrerPage = Session.Item("referrerPage")
End If
End Try
If StrComp(referrerPage, "wizard.aspx") <> 0 And String.IsNullOrEmpty(Session.Item("referrerPage")) Then 'Initialize Session state to remember "referrerPage"
Session.Add("referrerPage", referrerPage)
End If
If StrComp(referrerPage, "formdetails.aspx") = 0 Then
If String.IsNullOrEmpty(Request.Params("id")) Then
'This line checks for an expected "id" param value and if none exists, forwards the page back to "tcom.aspx"
Response.Redirect(Request.UrlReferrer.AbsolutePath)
Else
ToggleView()
End If
End If
End Sub
'Prefill Dynamic controls here.
Private Sub Page_PreLoad(sender As Object, e As EventArgs) Handles Me.PreLoad
If Not IsPostBack Then
productLine_ddl.DataBind()
docType_ddl.DataBind()
requestType_ddl.DataBind()
'...and several more DataBinds for each individual
' control in the wizard. Nothing more.
End If
End Sub
Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
If Not IsPostBack Then
'Benign code for querying the database to get User info for Page.User.Identity.Name
End If
End Sub
Protected Sub Page_PreRender(ByVal sender As Object, ByVal e As EventArgs) Handles Me.PreRender
If Not IsPostBack Then
'Here is completely benign code for hiding a couple controls.
End If
End Sub
Protected Sub Page_PreRenderComplete(ByVal sender As Object, ByVal e As EventArgs) Handles Me.PreRenderComplete
'PREFILL HERE when appropriate. This occurs after checking the "referrerPage" and ensuring a value for the "id" parameter.
If Not IsPostBack Then
Try
If Not String.IsNullOrEmpty(Request.Params("id")) Then
PrefillWizard(Request.Params("id"))
Else : output.Text += "Source: " + Request.UrlReferrer.AbsolutePath
End If
Catch ex As Exception
End Try
End If
End Sub
To anyone who can help with this, you have my eternal gratitude. ;)
The problem is that the control tree of the page must be exactly the same during every postback. That means that you have to add all the control every time no mater which ActiveViewIndex is set. Preferably in CreateChildControls or page init. In the ToggleView function you can than set the visibility of the controls.