Is there any way do delay the autopostback on a dropdownlist until the list actually loses focus? I want to accept input from the keyboard without the page posting back after every keystroke. For example, take this code:
<asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="true">
<asp:ListItem >Test1</asp:ListItem>
<asp:ListItem >Tst1</asp:ListItem>
<asp:ListItem >twotest</asp:ListItem>
</asp:DropDownList>
Say I want to select twotest. I tab to the ddl and input 'tw' into my keyboard. However, as soon as the 't' is entered, the page automatically posts back, while the 'w' input is lost. Resetting focus doesn't really help any as then the ddl thinks that 'w' is the first input. Any help would be appreciated.
It seems impossible. You must remove AutoPostBack="true" and try another way to perform postback. Consider below solution:
when dropdown ddlCountry changed, the function ddlCountry_changed is called that trigger btnLoad click to perform postback. The button btnLoad is put inside an update panel so the page is not reload and you still have focus on the dropdown.
<script type="text/javascript">
function ddlCountry_changed() {
document.getElementById('<%= btnLoad.ClientID %>').click();
}
</script>
Country:
<asp:DropDownList ID="ddlCountry" runat="server" onchange="ddlCountry_changed();">
<asp:ListItem Text="Vietnam" Value="1"></asp:ListItem>
<asp:ListItem Text="United State" Value="2"></asp:ListItem>
</asp:DropDownList>
<asp:UpdatePanel ID="updatePanel" runat="server">
<ContentTemplate>
<asp:Button ID="btnLoad" style="display: none" runat="server" OnClick="btnLoad_OnClick" />
</ContentTemplate>
</asp:UpdatePanel>
It's a little more complicated than just handling the blur. You need to remove the onchange attribute (AutoPostBack="false") so keyboard navigation is possible and attach event handlers that submit the form when the value has changed via clicking, blur, or the enter key is pressed.
I ran into this same issue and created a plugin for handling this. Check out https://github.com/bstruthers/AutoPostBack-Fix.
Related
SO far everything working ok, button is disabled until value is selected from the drop down list,
However I want ---select--- to be the first option on the drop down list, but this is not happening...any ideas as to why?
<asp:DropDownList ID="DropDownListSubContractors" runat="server"
AppendDataBoundItems="true" DataTextField="Company_Name" DataValueField="id"
onchange='selectChanged(this);'>
<asp:ListItem Text="---Select---" Value="0" />
<asp:ListItem Text="Option 1" Value="1" />
</asp:DropDownList>
<script type="text/javascript">
function selectChanged(e) {
document.getElementById("<%= addNewSubContractor.ClientID %>").disabled
= (e.options[e.selectedIndex].value == "0") ? "disabled" : "";
}
</script>
<asp:Button ID="addNewSubContractor" Text="Add Sub Contractor"
OnClick="UploadSubContractor" runat="server" disabled='disabled' />
Showing the manually added items first followed by the data bound items is the default behavior of the drop down list, so ---Select--- should in theory be the first item.
I suspect there is some logic elsewhere(can be javascript or code behind) which sets the selected item to something else i.e:
DropDownListSubContractors.SelectedIndex = 1;
Have a good look through your code and make sure the selected item is not being re-set anywhere
Have you got append databound item set to true, this checks to see if there are any items in the collection, and adds them first before binding?
I have a repeater with a RadioButtonList inside the ItemTemplate, but when the RadioButtonList.OnSelectedIndexChanged event fires it generates a full postback. What have I done wrong in my code below? How can I get the OnSelectedIndexChanged to generate an Async Postback?
<asp:UpdatePanel runat="server" ID="UpdatePanel2">
<ContentTemplate>
<asp:Repeater ID="Repeater1" runat="server" DataSourceID="sqlOptions">
<ItemTemplate>
<asp:UpdatePanel runat="server" ID="pnlA">
<ContentTemplate>
<strong>
<%# Eval("Name") %></strong><br />
<asp:RadioButtonList ID="RadioButtonList1"
DataSourceID="sqlOptionValues" runat="server"
DataTextField="id" DataValueField="Id" AutoPostBack="true"
OnSelectedIndexChanged="LoadPrice"
ValidationGroup="options" />
<asp:RequiredFieldValidator ID="RequiredFieldValidator1"
ForeColor="Red" runat="server"
ControlToValidate="RadioButtonList1"
ErrorMessage="Required Field"
ValidationGroup="options" />
<asp:SqlDataSource ID="sqlOptionValues" runat="server"
ConnectionString="<%$ ConnectionStrings:
ConnectionString6 %>"
SelectCommand='<%# "SELECT DISTINCT OptionValue.Name,
OptionValue.Id FROM CombinationDetail
INNER JOIN OptionValue
ON CombinationDetail.OptionValueId = OptionValue.Id
WHERE (OptionValue.OptionId =" +
Eval("Id") + ")" %>'>
</asp:SqlDataSource>
<br />
</ContentTemplate>
</asp:UpdatePanel>
</ItemTemplate>
</asp:Repeater>
</ContentTemplate>
</asp:UpdatePanel>
Many thanks for any help :)
This is a real-world use case. I have a page with Repeaters, Ajax Accordions inside of other Accordions, Update Panels inside other Update panels, you name it. The page works great, except when I want to update one of the Accordion panels with my RadioButtonList (RBL). Even with the RBL inside an update panel, it causes a postback of the entire page. I tried everything. I finally realized it wasn't me when I noticed my buttons would work just fine. I figure it must be a bug in either the framework or the Ajax Control Toolkit. I did find people reference this link all over the web (http://blog.smarx.com/posts/the-case-of-the-radiobuttonlist-half-trigger.aspx), but this link from 2007 is dead now and probably no longer applicable, so that's no help.
What I ended up doing was going with what works - that submit button. All I did was add an onclick attribute to the RBL to call a hidden button. Now you don't want to set the button to Visible=false because then the button won't appear in the generated markup. Instead, set the button's style to display:none; so that no one will see this hack, because yes, that's what this workaround is - it's a hack, but simple and just as effective as what you'd expect. Don't forget to remove the Autopostback="True" from your RBL.
CAVEAT: Because I'm using a hacked button for the onclick event, it's possible for the user to click in the area of the RBL, but not actually select an item. When this happens, our onclick triggers an AsyncPostBack and the codebehind logic will be processed, so please keep that in mind. To give you an idea of what I mean: all the Page_Load() events will be called, but rbl_Questions_SelectedIndexChanged() won't be if they happen to click in the area of the RBL without actually selecting an item. For my purposes this causes no issues in my logic and has no effect on the user.
Here's the Code:
Somewhere In the .Aspx Page:
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:RadioButtonList ID="rbl_Questions" runat="server"
OnSelectedIndexChanged="rbl_Questions_SelectedIndexChanged">
</asp:RadioButtonList>
<asp:Button ID="btn_rbl_Questions" runat="server" style="display:none;"/>
<asp:Label ID="lbl_Result" runat="server" Text="" Visible="false">
</asp:Label>
</ContentTemplate>
</asp:UpdatePanel>
In the Page_Load() event:
protected void Page_Load(object sender, EventArgs e)
{
if (IsPostBack == false)
{
//Instead of using the AutoPostback of the RBL, use this instead.
rbl_Questions.Attributes.Add("onclick",
"document.getElementById('"
+ btn_rbl_Questions.ClientID
+ "').click();");
//Bind your RBL to a DataSource, add items programmatically,
// or add them in the aspx markup.
}
}
In the rbl_Questions_SelectedIndexChanged() event:
protected void rbl_Questions_SelectedIndexChanged(object sender, EventArgs e)
{
//Your code here.
//My code unhid the lbl_Result control and set its text value.
}
Update 05/24/2011
The above "hack" is no longer necessary (I am leaving it above since this was marked as the answer by the author). I have found the best way to do this, thanks to this SO Answer:
Updatepanel gives full postback instead of asyncpostback
The code is much simpler now, just remove what I put in the Page_Load() method and remove the Button I used in the Aspx page and add ClientIDMode="AutoID" and AutoPostBack="True" to the control you want the UpdatePanel to capture.
Somewhere In the .Aspx Page:
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:RadioButtonList ID="rbl_Questions" runat="server"
ClientIDMode="AutoID" AutoPostBack="true"
OnSelectedIndexChanged="rbl_Questions_SelectedIndexChanged">
</asp:RadioButtonList>
<asp:Label ID="lbl_Result" runat="server" Text="" Visible="false">
</asp:Label>
</ContentTemplate>
</asp:UpdatePanel>
MS changed how ClientID's are generated in .net 4.0 from "AutoID" to "Predictable" and I guess the ScriptManager or UpdatePanel's weren't updated correctly to use it. I can't find documentation on why that is anywhere or if it was left that way by design.
I seriously don't miss winforms.
Try this:
<asp:UpdatePanel runat="server" UpdateMode="Conditional" ID="pnlA">
You'll also need to setup
<Triggers>
//radio buttons
</Triggers>
Not sure how you'll do that since it's a dynamically built list.
If have the below markup.
<asp:checkbox id="chkTVLic" runat="server" text="TV Licence" oncheckedchanged="chkDocs_CheckChanged"
autopostback="true" CausesValidation="false" />
<asp:panel id="pnlTVLic" runat="server" visible="false">
<div class="toggle-item-link1 document-date">
<asp:panel id="pnlTVLicIssueDate" runat="server">
<p>
Please enter the date of issue
</p>
<div class="fm-req">
<asp:textbox id="txtTVLicIssueDate" cssclass="tb size2" runat="server" onblur="return true;"></asp:textbox>
<cc2:calendarextender id="caleTVLicIssueDate" runat="server" targetcontrolid="txtTVLicIssueDate"
popupbuttonid="ibnTVLicIssueDate" popupposition="BottomLeft" animated="true"
format="dd/MM/yyyy">
</cc2:calendarextender>
<asp:imagebutton id="ibnTVLicIssueDate" runat="server" imageurl="../images/img-calendar-day.png"
alternatetext="Calendar" tooltip="Pick Date" cssclass="date-picker" />
<asp:requiredfieldvalidator id="rfvTVLicIssueDate" CssClass="error" runat="server" controltovalidate="txtTVLicIssueDate"
display="Dynamic" errormessage="Required" setfocusonerror="true" validationgroup="TVLic"></asp:requiredfieldvalidator>
<asp:comparevalidator id="cmvTVLicIssueDate" CssClass="error" runat="server" errormessage="Not a valid date"
controltovalidate="txtTVLicIssueDate" operator="DataTypeCheck" type="Date" setfocusonerror="true"
validationgroup="TVLic" display="Dynamic" cultureinvariantvalues="true"></asp:comparevalidator>
<asp:customvalidator id="cuvTVLicIssueDate12Months" CssClass="error" runat="server" controltovalidate="txtTVLicIssueDate"
validationgroup="TVLic" display="Dynamic" onservervalidate="cuvDocIssueDate12Months_ServerValidate"
errormessage="Document must be less than 12 months old."></asp:customvalidator>
</div>
</asp:panel>
<asp:panel id="pnlTVLicApprove" runat="server">
<asp:LinkButton id="lbnTVLicApprove" runat="server" CssClass="screen-hide"
alternatetext="Confirm TV Licence" tooltip="Confirm TV Licence" Text="OK" CausesValidation="false" OnClick="lbnApproveConfirm_Click" />
<asp:imagebutton id="ibnTVLicApprove" runat="server" imageurl="../images/img-accept-doc-off.png"
alternatetext="Approve" tooltip="Approve" cssclass="approval-btn" causesvalidation="true" validationgroup="TVLic" OnMouseDown="HandleApproveClick('TVLic','lbnTVLicApprove');return false;" OnClientClick="HandleApproveClick('TVLic','lbnTVLicApprove');return false;" />
<span class="approval-label">Accept document:</span></asp:panel>
</div>
</asp:panel>
The app is written in c# but i havn't posted any actual code as all the user code related to this markup seems to work fine.
The problem is the CheckBox chkTVLic has causes validation set to false and autopostback set to true. So whatever happens when i check and uncheck the checkbox it should postback. Most of the time this is exactly what it does and the result is to show and hide pnlTVLic when it is checked and unchecked. However if any on the validators within the panel fire, the checkbox does not cause a postback the first time. It will on all subsequent times but never the first. However it should ALWAYS cause a postback. What could be stopping it. Before someone asks there is no use written client side code, everything is pure .net markup and c# code.
I don't see why it shouldn't postback when you check/uncheck the checkbox, but if the only purpose of that checkbox is to hide/unhide a panel, I would rather do it in javascript. Doing a full postback to the server just for hiding some panel seems really bad.
In javascript you can do this to hide the panel:
document.getElementById('<%=pnlTVLic.ClientID%>').display='none';
And this to show it:
document.getElementById('<%=pnlTVLic.ClientID%>').display='block';
It's going to be so much faster and better. Just put a regular checkbox instead of the ASP.NET one and subscribe to the onclick event.
Sorry, one more comment:
I think you are wrong when you say that the checkbox should ALWAYS cause a postback. No, if one of the validators fires inside the panel, the checkbox will not cause a postback until the condition is satisfied.
This is what I did and it worked.
on checkbox onclick event I disabled all the validation controls and immediately did Page_ClientValidate(); and it worked.
I'm trying to show message "Loading..." when a user select an item in the dorp down list.
Mark up:
<asp:Label ID="lbl_LoadingMessage" runat="server" ></asp:Label>
<asp:DropDownList ID="ddl_Chapter" runat="server" AutoPostBack="True">
</asp:DropDownList>
Code behind:
Protected Sub LoadMessage()
lblLoading.Text = "Loading..."
End Sub
Protected Sub ddl_Chapter_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ddl_Chapter.SelectedIndexChanged
LoadMessage()
Dim redirectURL As String = "~/chapter.aspx?bid=" & BookId.ToString
Server.Transfer(redirectURL)
End Sub
The method I'm using above is not working. When I select a new item from the drop down list, it works as expected except the message "Loading..." is not showing at all. Any suggestion or code sample? Thank you.
You will have to do this on the client side using javascript.
At the moment, your dropdown menu is causing a postback. when the drop down menu is changed, the page post backs then the entire page life cycle is run through. When the event ddl_Chapter_SelectedIndexChanged is run, you set the text of the loading label, but you never reload the page (which would have your loading message) - instead you server.transfer to a new page.
If you use jQuery, you could set the labels text value as soon as the dropdown is changed
something like:
$('#the_full_renedered_ID_of_ddl_Chapter').change(function () {
$('#the_full_renedered_ID_of_lbl_LoadingMessage').html("Loading...")
});
Or use javascript:
<script type="text/javascript" src="http://jqueryjs.googlecode.com/files/jquery-1.3.2.min.js" /></script>
<script type="text/javascript">
$(document).ready( function() {
$("#<%= ddl_Chapter.ClientID %>").change(function()
{
window.alert("Loading");
});
});
</script>
The whole event will execute before the page re-rendering will take place.
If you are going to be doing extra processing between the LoadMessage() and the Server.Transfer try using AJAX UpdateProgress panel and adding your "loading..." message to that and add your dropDownList to a UpdatePanel.
This way depending on what code needs executing in your SelectedIndexChanged event it will show the "loading..." message before it via a partial page postback.
e.g
<asp:ScriptManager id="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:UpdateProgress id="UpdateProgress1" runat="server" associatedUpdatePanelID="UpdatePanel1">
<ProgressTemplate>
<p>Loading....</p>
</ProgressTemplate>
</asp:UpdateProgress>
<asp:UpdatePanel id="UpdatePanel1" runat="server" childrenAsTriggers="true">
<ContentTemplate>
<asp:DropDownList id="DropDownList1" runat="server" autoPostBack="true">
<asp:ListItem selected="True" value="1">Book 1</asp:ListItem>
<asp:ListItem value="2">Book 2</asp:ListItem>
<asp:ListItem value="3">Book 3</asp:ListItem>
<asp:ListItem value="4">Book 4</asp:ListItem>
<asp:ListItem value="5">Book 5</asp:ListItem>
</asp:DropDownList>
<asp:Label id="lblSelected" runat="server"></asp:Label>
</ContentTemplate>
</asp:UpdatePanel>
This way the "loading..." message will be displayed for the duration of the processing of what you are trying to achieve in your SelectedIndexChanged event. If this is simply for display reasons javaScript would be your best bet.
I have three radio buttons on a form - A, B, C. Each of these selections populates a dropdown list with data specific to the option. When the form loads, I set option A to be checked (as the default).
When I select buttons B or C, the AsyncPostBack triggers fine and the dropdown is populated. BUT, subsequently selecting A from either B or C does not trigger the event.
I suspect that because A was checked when the form loaded, the browser is not seeing any "change" to raise the event.
So what can be done to enable the default A button recognise it is being changed from B or C in order to raise the postback?
I have tried both setting the checked state of button A in code on inital loading of the page only (ie IsPostBack is False) and alternatively setting the checked attribute of the radiobutton in the html, with the same results. If I don't default the radio button the functionality works as expected, except I don't have the radio button and dropdown list defaulted when the page first loads.
The html...
<asp:RadioButton ID="radBook" runat="server" AutoPostBack="true" GroupName="grpArticleType" Text="Book" />
<asp:RadioButton ID="radCD" runat="server" AutoPostBack="true" GroupName="grpArticleType" Text="CD" />
<asp:RadioButton ID="radDVD" runat="server" AutoPostBack="true" GroupName="grpArticleType" Text="DVD" />
<asp:UpdatePanel ID="pnlTasks" runat="server" UpdateMode="Conditional" RenderMode="Inline">
<ContentTemplate>
<asp:DropDownList ID="dropShippingSize" runat="server" CssClass="dropdownMandatory"></asp:DropDownList>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="radBook" />
<asp:AsyncPostBackTrigger ControlID="radCD" />
<asp:AsyncPostBackTrigger ControlID="radDVD" />
</Triggers>
</asp:UpdatePanel>
The code behind...
Sub Page_Load
If Not Me.IsPostBack Then
radBook.Checked = True
End If
End Sub
Private Sub rad_CheckedChanged(ByVal sender As Object, ByVal e As System.EventArgs) _
Handles radBook.CheckedChanged, radCD.CheckedChanged, radDVD.CheckedChanged
zLoadShippingSizeDropdown()
End Sub
I had the same problem and looked for an answer for hours. This seems to have nothing to do with ViewState or anything similar, but with some kind of incompatibility of using a pre-checked RadioButton as trigger for an Async PostBack.
The work around I found is amazingly easy and worked right away; instead of using the checked=true on the mark-up or myRadioButton.Checked on the server side, I did the following:
Not setting the attribute on Mark-up and add this on the Page_Load event:
if (!IsPostBack)
{
MyRadioButton.InputAttributes["checked"] = "true";
...
}
I hope this helps and saves some people hours of hair pulling :)
I'm guessing you need to need to check if the page is a postback in your load event:
protected void Form_Load(object sender, EventArgs e)
{
if (!Page.IsPostback)
{
// Set radiobutton A...
}
}
We had the same problem and it seems you will have to set the other "checked" property for radio buttons to "false".
So please add the lines
radCD.Checked = False
radDVD.Checked = False
Are you by chance handling viewstate in your code behind as well? If so then you need to handle the AJAX version of it as viewstate can often be lost on AJAX style pages. Try putting your buttons inside the update panel and see if you get the same behaviour if the panel has it's update mode set to conditional. Don't worry about the postback triggers if you do that.
The asynch triggers are only for items inside an update panel. any item outside of a panel will doa full postback by design.
<asp:UpdatePanel ID="pnlTasks" runat="server" UpdateMode="Conditional" RenderMode="Inline">
<ContentTemplate>
<asp:RadioButton ID="radBook" runat="server" AutoPostBack="true" GroupName="grpArticleType" Text="Book" />
<asp:RadioButton ID="radCD" runat="server" AutoPostBack="true" GroupName="grpArticleType" Text="CD" /><asp:RadioButton ID="radDVD" runat="server" AutoPostBack="true" GroupName="grpArticleType" Text="DVD" />
<asp:DropDownList ID="dropShippingSize" runat="server" CssClass="dropdownMandatory">
</asp:DropDownList>
</ContentTemplate>
</asp:UpdatePanel>
WOW, I would have never thought that could be the bug. Saved many hours of frustration.
Thanks Juan going through the carppy Microsoft issue and found a solution for the rest.