I have a page that contains a Repeater, which contains server control elements, within an UpdatePanel and while all other controls behave normally, the Drop Down control causes a full postback every time.
<asp:Repeater ID="rpt" runat="server">
<ItemTemplate>
<asp:SomeWorkingControl ID="swc" runat="server" />
<asp:DropDownList ID="ddl" runat="server" OnSelectedIndexChanged="ddl_SelectedIndexChanged" AutoPostBack="true">
<asp:ListItem Text="0" Value="0" />
<asp:ListItem Text="1" Value="1" />
</asp:DropDownList>
</ItemTemplate>
</asp:Repeater>
This is vaugely what my code looks like, the DropDownList control is actually in a UserControl, but the theory is the same.
If I apply an event to SomeWorkingControl then there is an Ajax postback and all is fine.
However, the event associated with the DropDownList causes a full postback! I know usually you would set an Async trigger for the DropDown, but since it is created in a repeater (and therefore I can not know how many there will be) so I don't really see how that could work.
Is there anybody who has experienced this before and knows a workaround perhaps?
Try to change this line:
<asp:DropDownList ID="ddl" runat="server" OnSelectedIndexChanged="ddl_SelectedIndexChanged" AutoPostBack="true">
for:
<asp:DropDownList ID="ddl" runat="server" OnSelectedIndexChanged="ddl_SelectedIndexChanged" AutoPostBack="true" ClientIDMode="AutoID">
Recently I had the same problem and I found out that the ClientIDMode can solve it.
Please have a look here: asp.net ClientIDMode Changes
Related
I have two drop down lists where one is inside an update panel and the other is outside.When the Index is changed on ddlFaculty the whole page is posted back instead of a partial for the contents in the update panel.
I have read in the ASP docs that sometime validation controls bog down update panels but im not too sure if that's the problem here.
<div class="form-group">
<asp:Label runat="server" AssociatedControlID="ddlFaculty" CssClass="col-md-2 control-label">Faculty</asp:Label>
<div class="col-md-10">
<asp:DropDownList ID="ddlFaculty" EnableViewState="true" class="form-control" CausesValidation="false" runat="server" autopostback="true" aria-expanded="true" ValidationGroup="g4" OnSelectedIndexChanged="ddlFaculty_SelectedIndexChanged">
<asp:ListItem Value="null">Select Faculty</asp:ListItem>
<asp:ListItem Value="Arts">Faculty of Arts</asp:ListItem>
<asp:ListItem Value="Business">Faculty of Business</asp:ListItem>
<asp:ListItem Value="Health">Faculty of Health</asp:ListItem>
<asp:ListItem Value="Industries">Faculty of Service Industries</asp:ListItem>
<asp:ListItem Value="Trades">Faculty of Trades</asp:ListItem>
<asp:ListItem Value="Maori">Te Wananga Maori</asp:ListItem>
</asp:DropDownList>
<asp:RequiredFieldValidator runat="server" ControlToValidate="ddlFaculty" ValidationGroup="g4"
CssClass="text-danger" Display="Dynamic" ErrorMessage="The faculty field is required." />
</div>
</div>
<div class="form-group">
<asp:Label runat="server" AssociatedControlID="ddlCourse" CssClass="col-md-2 control-label">Course</asp:Label>
<div class="col-md-10">
<asp:UpdatePanel runat="server" id="UpdatePanel1" UpdateMode="Conditional">
<ContentTemplate>
<asp:Label runat="server" id="lblfaculty"></asp:Label>
<asp:DropDownList runat="server" CssClass="form-control" ID="ddlCourse" ValidationGroup="g7" />
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="ddlFaculty" EventName="SelectedIndexChanged"/>
</Triggers>
</asp:UpdatePanel>
<asp:RequiredFieldValidator runat="server" ControlToValidate="ddlCourse" ValidationGroup="g7"
CssClass="text-danger" Display="Dynamic" ErrorMessage="The course field is required." />
</div>
</div>
Try using the AsyncPostBackTrigger property of the UpdatePanel.
See: How to stop UpdatePanel from causing whole page postback?
Did you try setting Button1 as an AsyncPostBackTrigger in the Triggers section, set the ChildrenAsTriggers property to true and the UpdateMode property to Conditional
Other solutions:
User control inside update panel causing full page postback
Full postback happens if your UpdatePanel cannot render its contents to a (e.g., when it is situated inside of ). So check you html inside of UpdatePanel, you might find the answer there (also, look for some incorrect xhtml, like incorrectly closed elements).
UpdatePanel causes full page postback
Unless you know of known issues that your site has when running in XHTML mode (and which you don't have time yet to fix), I'd always recommend removing the section from your web.config file (or you can explicitly set it to "Transitional" or "Strict").
This will make your HTML output standards compliant. Among other things, this will cause the HTML from your server controls to be "well formed" - meaning open and close tag elements always match. This is particularly important when you are using AJAX techniques to dynamically replace the contents of certain HTML elements on your page (otherwise the client-side JavaScript sometimes gets confused about container elements and can lead to errors). It will also ensure that ASP.NET AJAX works fine with your site.
It turns out that the page was infact sending a partial postback but I had mistaken the scroll to the top of the page when the postback had been recieved as a full page post back
i have successfully completed my web application for an organization and it works up to expectations but i noticed one problem and tried to cure it via searching on Google and asking seniors but none of these helped much.
Problem:
I have multiple drop downs lists on page, in which selecting value in one drop down triggers the loading of another drop down i.e. Country > cities situation, problem is that whenever i click any value it scrolls page to the top and i have to scroll back again then again and again which realy looks bad and unprofessional. Please help me.
Code:
<asp:UpdatePanel ID="updGridViewSMS" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<br />
<asp:Panel ID="pnlBoxesDropDowns" runat="server">
<label style="width:400px">Relevant Region</label>
<asp:DropDownList ID="ddlRegions" runat="server" CssClass="DropDown_Width" Width="147px" OnSelectedIndexChanged="ddlRegions_SelectedIndexChanged" AppendDataBoundItems="True" AutoPostBack="true" >
<asp:ListItem Value="-1" Selected="True">-Select-</asp:ListItem>
</asp:DropDownList>
<asp:RequiredFieldValidator ID="ReqFieldValidatorRegions" runat="server"
ControlToValidate="ddlRegions" ErrorMessage="Region is Required" InitialValue="-1"
ForeColor="Red" ValidationGroup="Complaints">Region is Required</asp:RequiredFieldValidator>
<label style="width:400px">Relevant District</label>
<asp:DropDownList ID="ddlDistricts" runat="server" CssClass="DropDown_Width" Width="147px" OnSelectedIndexChanged="ddlDistricts_SelectedIndexChanged" AutoPostBack="true">
</asp:DropDownList>
<asp:RequiredFieldValidator ID="ReqFieldValidatorDistricts" runat="server"
ControlToValidate="ddlDistricts" ErrorMessage="Region is Required" InitialValue="-1"
ForeColor="Red" ValidationGroup="Complaints">District is Required</asp:RequiredFieldValidator>
<label>Relevant P.Station</label>
<asp:DropDownList ID="ddlPoliceStations" runat="server" Width="147px" CssClass="DropDown_Width">
</asp:DropDownList>
<asp:RequiredFieldValidator ID="ReqFieldValidatorPoliceStations" runat="server"
ControlToValidate="ddlPoliceStations" ErrorMessage="Police Station is Required" InitialValue="-1"
ForeColor="Red" ValidationGroup="Complaints">Police Station is Required</asp:RequiredFieldValidator>
<label>Priority</label>
<asp:DropDownList ID="ddlPriority" runat="server">
<asp:ListItem Text="Top" Value="1"></asp:ListItem>
<asp:ListItem Text="Normal" Value="2"></asp:ListItem>
</asp:DropDownList>
</asp:Panel>
<br />
<br />
<asp:Timer runat="server" Interval="60000" ID="RefreshSmsComplaints" OnTick="RefreshSmsComplaints_Tick" />
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="RefreshSmsComplaints" EventName="Tick" />
</Triggers>
</asp:UpdatePanel>
help please.
The core issue here is that you are posting back to the server on every dropdown select. This means that the web page reloads, because it is your webserver that updates the HTML versus the more modern way to do things which is to have javascript do it on the client. Here is a hacky, imperfect, but quick solution:
In the browser, inspect your html DOM. Each of your dropdown ASPX tags should have been replaced with something along the lines of
<select id="ctl000$ddlDistricts"...
You can use url hashtags to scroll to that area by appending #ctl000$ddlDistricts to the url. Since the server knows which control was posted, it can get the control's client-side ID, and write it into the following javascript (preferably at the bottom of the page).
<script type="text/javascript">
location.href='#' + <%=PostedControl.ClientID %>
</script>
Why is this imperfect? Because it will scroll your page to a point where the dropdown is at the top edge of the browser. This means that if a user selects the dropdown with it halfway down the page, once the page reloads, that will be at the top. At the very least, however, your dropdowns will then be within view.
Your original question indicated that you wanted the page to look "professional" and while this gets the job done, it is imperfect, as will all solutions be when you are dealing with classic ASPX webforms-style postbacks. Specifically, your dropdowns have something that looks like this:
OnSelectedIndexChanged=MyFunction
What this tells the ASPX form is, in essence, "when you render this dropdown control into HTML, add something into the tag like onChange="postMyFormBackToServerCausingReloadAndPageScroll. What you really want, perhaps, is to have it do onChange=GetNewDropdownFromServerAndReplaceOnPageWithoutReload. That involves more knowledge than I can add to an already long answer, but here are some helpful links:
http://www.codeproject.com/Articles/691298/Creating-AJAX-enabled-web-forms (a bit old but probably a good stepping stone)
http://www.codedigest.com/Articles/jQuery/318_Doing_AJAX_with_jQuery_in_ASPNet.aspx (a slightly more modern way to do it, but you do more yourself with this method as opposed to relying on .NET)
Lastly, the fully modern way to do things that involves completely rewriting your page
http://www.codeproject.com/Articles/575397/An-Absolute-Beginners-Tutorial-on-ASP-NET-MVC-for (not sure if this is the right article for you, just google for ".NET MVC")
I have an ASP Drop Down List that opens then immediately collapses on one click. I'm using a Drop Down on another page with the same CssClass, and it's working fine (first click expands the DDL and the second click collapses it). Anyone have any idea what could be happening? I would greatly appreciate any suggestions or input.
<label>
<asp:RadioButton ID="rbToAccount" runat="server" GroupName="rbTo" />
Account
<asp:DropDownList ID="ddlToAccount" runat="server" CssClass="span4 m-wrap">
</asp:DropDownList>
</label>
Try This :
<label></label>
<asp:RadioButton ID="rbToAccount" runat="server" GroupName="rbTo" />
Account
<asp:DropDownList ID="ddlToAccount" runat="server" CssClass="span4 m-wrap">
</asp:DropDownList>
is the event tied to a Jquery function??
It sounds like on dropdown list change it is causing a postback, which then is refreshing the page to it's original state. Try adding OnClientClick="return false" as an attribute to the ddl control
I have a drop down list in UpdatePanel_2, it gets populated when Button_1 is clicked in UpdatePanel_1.
My ddlist markup is,
<asp:DropDownList id="drop1" runat="server" EnableViewState="true" AutoPostBack="true" OnSelectedIndexChanged="Drop1_SelectedIndexChanged" />
then code behind is,
protected void Drop1_SelectedIndexChanged(object sender, EventArgs e)
{ }
I also tried putting AutoPostback=true to my DropDownList, still no success.
I also added triggre to update panel 2 but no gain,
<Triggers>
<asp:AsyncPostbackTrigger ControlID="drop1" EventName="SelectedIndexChanged" />
</Triggers>
I am populating DropDownList using a button not PAGE LOAD METHOD PLEASE READ before answering.
Thanks
Check the data to populate the DropDownList in the Page_Load event and always check IspostBack:
if(!IsPostBack)
{
//DropDownList configuration
}
Use EnableViewState:
<asp:DropDownList ID="ddlAddDepPlans" runat="server" AutoPostBack="true" EnableViewState="true" />
Hope it helps you.
I had the same issue. My problem was that the values of my ListItems were all the same :D
<asp:DropDownList ID="ddlFilterLogins" runat="server" Visible="true" AutoPostBack="true">
<asp:ListItem Value="0" Text="All"></asp:ListItem>
<asp:ListItem Value="0" Text="Some"></asp:ListItem>
<asp:ListItem Value="0" Text="Some more"></asp:ListItem>
</asp:DropDownList>
It should be like this:
<asp:DropDownList ID="ddlFilterLogins" runat="server" Visible="true" AutoPostBack="true">
<asp:ListItem Value="0" Text="All"></asp:ListItem>
<asp:ListItem Value="1" Text="Some"></asp:ListItem>
<asp:ListItem Value="2" Text="Some more"></asp:ListItem>
</asp:DropDownList>
Hope this helps. This might be hard to find sometimes :)
Please, when you initialize it in Page_Load() check if not is postback. If you don't do it, you will always set the default value, and this replaces the value setted in the event.
if(!IsPostBack)
{
//DropDownList configuration
}
You can use Init event instead of SelectIndexChanged.
It worked fine for me.
Hope you got my point.
It was also a wired problem for me. finally It was because of identical listitems in the dropdown as shown below. during development you may use same items just for testing. change them.
<asp:ListItem>Business</asp:ListItem>
<asp:ListItem>Business</asp:ListItem>
<asp:ListItem>Business</asp:ListItem>
<asp:ListItem>Business</asp:ListItem>
So I am using a Repeater inside a form to display a list of questions that are retrieved from a database.
Each Question allows the end user to select Yes or No and add some additional Text like this.
<ItemTemplate>
<asp:Panel runat="server">
<asp:RadioButtonList RepeatDirection="Horizontal" CssClass="YesNo" ID="YesNo" runat="server">
<asp:ListItem Value="Yes" Text="Yes" />
<asp:ListItem Value="No" Text="No" />
</asp:RadioButtonList>
</asp:panel>
<asp:Panel runat="server" CssClass="MoreInfo">
<asp:TextBox ID="TextBox1" TextMode="MultiLine" Height="70px" Rows="10" Columns="25" Wrap="true" runat="server" CssClass="MoreInfoText"></asp:TextBox>
</asp:Panel>
</ItemTemplate>
The repeater is databound to a datatable in the PageLoad event.
One on the fields in the datatable is the Question's number.
So when the data is posted how can I tell which question # each answer (Yes or No and additional Text) is refering to?
If I were generating the HTML by hand instead of using a Server Control I could just make the name of the html element that will be posting data like
name=variableHoldingQuestionNumber + YesNo
name=variableHoldingQuestionNumber + AdditionalComments
But I can't seem to use a variable when setting the Name attribute inside a Repeater Item.
Is abandoning the Server Control and writing the HTML myself my only solution.
Bind the questions number to a hidden field and when the save comes back, grab that hidden field back off and take the number out of it. Then you know which question you are looking at.
Put a break point on page load and do a postback. Take a deep look at Request.Form key/value pair collection. Everything from the post will be in there, with predictable labels/indexs.