Bit confused about this. I was under the impression that if you added server controls to the ItemTemplate of a repeater then the ID's assigned to those controls would persist across postbacks and the state would be maintained. But it doesn't seem to be happening. Here's my ItemTemplate:
<asp:HiddenField ID="hidPending" runat="server" value="<%# DataBinder.Eval(Container.DataItem, "Id")%>" />
<td class="leftpadd"><uc:restrictedtext ID="uclblCategory" runat="server" Width="125" /></td>
<td style="border-left:1px solid #528ABD;" class="leftpadd"><%# DataBinder.Eval(Container.DataItem, "SelectedOptions")%></td>
<td style="border-left:1px solid #528ABD;" class="leftpadd"><%# DataBinder.Eval(Container.DataItem, "Price.IncludingTax", "{0:C}")%></td>
<td style="border-left:1px solid #528ABD;" class="leftpadd"><%# DataBinder.Eval(Container.DataItem, "ExtrasCost", "{0:C}")%></td>
<td style="border-left:1px solid #528ABD;" class="leftpadd"><%# DataBinder.Eval(Container.DataItem, "Quantity", "{0:000}")%></td>
<td style="border-left:1px solid #528ABD;" class="leftpadd"><asp:CheckBox ID="chkPendingItems" runat="server" /></td>
Which populates fine. What I'm looking to happen is for the user to be able to select certain items from the repeater using the checkbox and "process" them (i.e. perform some data operations on those items) on clicking a button which is outside the repeater. Here's my button click code:
Private Sub lnkPendingProcessSelected_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles lnkPendingProcessSelected.Click
For Each rItem As RepeaterItem In rptPendingItems.Items
If rItem.ItemType = ListItemType.Item Or rItem.ItemType = ListItemType.AlternatingItem Then
Dim chk As CheckBox = DirectCast(rItem.FindControl("chkPendingItems"), CheckBox)
If chk.Checked Then
Dim orderItemId As Integer
Dim hid As HiddenField = DirectCast(rItem.FindControl("hidPending"), HiddenField)
orderItemId = CInt(hid.Value)
My.Application.ManagerFactory.OrderManagerInstance.ChangeOrderItemStatus(orderItemId, Concrete.Cms.DataTransferObjects.OrderItemStatus.Processing)
End If
End If
Next
End Sub
But if you step through this, the checkboxes are found and assigned correctly but their Checked attribute is always False. Anyone have any suggestions as to why state isn't being maintained and what I can do about it?
Based on CyberDude's comment, you're probably reseting the values when you databind. If possibly, try using IsPostback to only databind on the first page load.
C#
if(!IsPostBack)
{
rptPendingItems.DataBind();
}
VB
If Not IsPostBack Then
rptPendingItems.DataBind()
End If
If that's not possible, or doesn't work, you'll probably have to get and set all of those checkbox values mannually, and persist them against your data set, or in session or summat.
I had a repeater inside a user control on a page with other user controls which cause post backs. In some cases, I wanted to rebind on postback so I created a bool property (IsDirty) on the page that I could set to true when I wanted to rebind the data on postback. Then in my page_load, I checked if (!IsPostBack || IsDirty) before databinding.
Related
I have two dropdownlists:
First one:
<asp:DropDownList ID="Drddl" class="form-control form-control-sm" Height="30" runat="server"
Width="350" Enabled="False" AppendDataBoundItems="true" AutoPostBack="true" DataTextField="FullName" DataValueField="Name">
</asp:DropDownList>
and gets filled on page load :
If Not Page.IsPostBack Then
FillDrData()
End If
The second:
<asp:DropDownList ID="Drddl" class="form-control form-control-sm" Height="30" runat="server" Width="350" Enabled="False" AppendDataBoundItems="true" AutoPostBack="true" DataTextField="FullName" DataValueField="Name"></asp:DropDownList>
and gets filled on SelectedIndexChanged of first one:
Private Sub Drddl_SelectedIndexChanged(sender As Object, e As EventArgs) Handles Drddl.SelectedIndexChanged
FillAgenceData()
End Sub
My question is:
Everything is working fine until I click submit button that read selected items from both dropdownlists and save it in SQL database. The Agenciesddl selecteditem always return to 1.
Be mindful of the postbacks of each dropdownlist. Quick and dirty way would be to set the selected values in ViewState or Session variables then get the variables on Submit. See below for rough example (pardon the c#)
Private void Drddl_SelectedIndexChanged(sender As Object, e As EventArgs)
{
ViewState["DrddlVal"] = Drddl.SelctedValue;
}
private void submit(sender As Object, e As EventArgs)
{
string dbparmval = ViewState["DrddlVal"].ToString();
}
As usual the answer is very simple.
the DataValueField property of DropDownList must be UNIQUE
when SelectedIndexChanged event triggered, the DropDownList goes to first value if he find more than one item has same value.
thanks for this article:
enter link description here
thanks everyone..
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 have a timer running on an Update Panel with a Listview showing a page size of 1. The timer increments the data pager as it cycles through many records.
In the Protected Sub timer_Tick Event I would like to read a few values from the ListView Page. Is there an easy way to do this?
The data is currently binding via a SQLDataSource, but this is temporary while other page development is underway. So I cannot rely on that data set for getting the info needed.
Something like....
val1 = listviewName.SelectedItems(0).SubItems(3).Text
val2 = listviewName.SelectedItems(0).SubItems(4).Text
One issue is that the record will not be selected. The Listview is displaying the data set in an ItemTemplate.
<ItemTemplate>
<tr>
<td>Position C:</td>
<td><asp:Label ID="Label50" runat="server" Text='<%# Eval "Pos_C") %>' />
</td>
</tr>
<tr>
<td>Position D</td>
<td><asp:Label ID="Label51" runat="server" Text='<%# Eval("Pos_D") %>' />
</td>
</tr>
</ItemTemplate>
Abbreviated layout of itemtemplate.
For anyone interested, I solved the above question with the code below....
Protected Sub ListView1_ItemDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.ListViewItemEventArgs) Handles ListView1.ItemDataBound
'Get the item object.
Dim dataItem As ListViewDataItem = CType(e.Item, ListViewDataItem)
Dim item As ListViewItem = e.Item
' Get the Label control in the item.
Dim myVal1Lbl As Label = CType(item.FindControl("Label50"), Label)
Dim myVal2Lbl As Label = CType(item.FindControl("Label51"), Label)
Dim myVal1 As String = myVal1Lbl.Text
Dim myVal2 As String = myVal2Lbl.Text
End Sub
Works great.
I am trying to loop through my repeater control and get the textbox values.
However, I am getting an error:
{"Object reference not set to an instance of an object."}
my code is:
Dim txtField As TextBox
Dim j As Integer = 0
'Confirm if user has entered atleast one quantity
For Each item In rptRequestForm.Items
txtField = rptRequestForm.FindControl("txtBox")
If txtField.Text <> Nothing Then
j += 1
Else
End If
Next
UPDATE: aspx code is:
<td><asp:Repeater ID="rptRequestForm" runat="server">
<HeaderTemplate>
<table border="0" width="100%">
<tr>
<td style="width:50%" class="TextFontBold"><asp:Label runat="server" ID="Label1" Text="Product"></asp:Label></td>
<td style="width:25%" class="TextFontBold"><asp:Label runat="server" ID="Label2" Text="Quantity"></asp:Label></td>
<td style="width:25%" class="TextFontBold"><asp:Label runat="server" ID="Label3" Text="Price (ea.)"></asp:Label></td>
</tr>
</table>
</HeaderTemplate>
<ItemTemplate>
<table border="0" width="100%">
<tr>
<td style="width:50%" class="TextFont"><span><%#Trim(Eval("Product_Title"))%></span></td>
<td style="width:25%"><asp:TextBox ID="txtBox" runat="server" Width="30%" onblur="Javascript:numberonly(this)"></asp:TextBox></td>
<td style="width:25%" class="TextFont"><span><%#Trim(FormatCurrency(Eval("Price")))%></span></td>
</tr>
</table>
</ItemTemplate>
</asp:Repeater>
try
Dim someString as String = "Not set" <-- used later to hold the values of the string
Dim txtField As TextBox
Dim j As Integer = 0
'Confirm if user has entered atleast one quantity
For Each item In rptRequestForm.Items
txtField = item.FindControl("txtBox")
If Not IsNothing(txtField) Then ' <--- this is the line I changed
j += 1
someString = txtField.Text ' <-- once you've checked and know that the textbox exists, you just grab the value like so.
' do whatever you like with the contents of someString now.
Else
End If
Next
The problem is that you're trying to access the ".Text" property of a TextBox that it didn't find. The TextBox itself is the object to which there is no reference.
Incidentally, the .Text property of an actual Textbox (one that exists and was found) can't be "Nothing". It can only be String.Empty or a valid string.
Edited my line of code
Sorry, my VB is rusty.
Final edit
AARGH! I'm blind. I can't believe I didn't see this. There were TWO problems withthe original code. This is the answer to the second issue:
Change
txtField = rptRequestForm.FindControl("txtBox")
to
txtField = item.FindControl("txtBox")
The ITEM has to find the control, not the repeater itself!
I created a small web app just to check to see if I was grabbing the textbox's text and finally found the issue above. my code is NOT the same as yours in the aspx, but here's a complete code listing so that you can see how it works:
vb code
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Dim t As New System.Data.DataTable
t.Columns.Add("Name")
Dim newRow(1) As Object
t.Rows.Add(New Object() {"Frank"})
t.Rows.Add(New Object() {"Dave"})
t.Rows.Add(New Object() {"Muhammad"})
rptRequestForm.DataSource = t
rptRequestForm.DataBind()
Dim txtField As TextBox
Dim j As Integer = 0 'Confirm if user has entered atleast one quantity
For Each item As RepeaterItem In rptRequestForm.Items
txtField = item.FindControl("txtBox")
If Not IsNothing(txtField) Then ' <--- this is the line I changed
j += 1
System.Diagnostics.Debug.WriteLine(item.ItemType.ToString())
System.Diagnostics.Debug.WriteLine(txtField.Text)
Else
System.Diagnostics.Debug.WriteLine(item.ItemType.ToString())
End If
Next
End Sub
aspx code
<asp:Repeater ID="rptRequestForm" runat="server">
<HeaderTemplate>
Hello!
</HeaderTemplate>
<ItemTemplate>
<asp:TextBox ID="txtBox" runat="server" Text='<%#Bind("Name") %>'></asp:TextBox>
<br />
</ItemTemplate>
</asp:Repeater>
produces the following output in the System.Diagnostics.Debug window:
Item
Frank
AlternatingItem
Dave
Item
Muhammad
The thread 0x321c has exited with code 0 (0x0).
The thread 0x39b8 has exited with code 0 (0x0).
You have to properly cast it as Textbox e.g.
TextBox txtField = (TextBox)rptRequestForm.FindControl("txtBox") // C# code
Here is VB.NET code:
Dim txtField As TextBox = CType(rptRequestForm.FindControl("txtBox"), TextBox)
Dim myText as string
Dim j As Integer = 0
'Confirm if user has entered atleast one quantity
For Each myItem as repeateritem In rptRequestForm.Items
If NOT string.isnullorempty(CTYPE(myItem.FindControl("txtBox"),textbox).text) then
j += 1
End If
Next
I wouldn't use nothing -- not sure that causes a problem or not, but usually I see that for objects, not properties. String.IsNullOrNothing() is made for checking strings for null or empty ("").
You don't need to worry about whether or not the textbox exists, because if it exists in one row of the repeater, it will exist in all rows. I guess you could check it for 'nothing' if you weren't sure what "txtBox" was at design time...but otherwise, not necessary.
You should definately use the cast (CTYPE()). I think you might be able to get away with not using it if all you want is .text, but the CTYPE gives you access to all of the textbox's properties (not just it's inherited properties), and also, you might need to do checkboxes or other controls at some point where you pretty much have to CTYPE in order to get to .ischecked, etc.
I made a generic method for set the property visible, I think you can take it as an example
Sub SetVisibleControlRepeater(ByRef repetidor As Repeater, ByVal idControl As String, ByVal esVisible As Boolean)
For Each item As RepeaterItem In repetidor.Items
Dim boton As System.Web.UI.WebControls.Button = CType(item.FindControl(idControl), Button)
boton.Visible = esVisible
Next
End Sub
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.