Develop Reference

Calling a function on a HTML check box change without submission using C#

I am using Visual Studio 2015 to create a ASP.NET web site. I have a DIV that is hidden by default and I am trying to display it if the user checks a check box. I am wondering if there is a way using C# to immediately display the DIV as soon as the user checks the box. I can't seem to find a way to recognize the change in state without the form being first submitted. I can easily achieve this using JavaScript however this is for a uni assignment and requires functionality to be implemented in C#.
This is the HTML for the checkBox:
<form id="form1" runat="server">
Limit Stations To My Location<asp:CheckBox ID="limitOptions" runat="server" onClick="toggleOptions()" />
<br /><br />
<div id="locationOptions" runat="server" hidden="hidden">
Radius (KM)<asp:TextBox ID="radius" runat="server" Text="100"></asp:TextBox>
<asp:Button ID="updateList" runat="server" Text="Button" OnClick="updateList_Click"/>
</div>
Any help would be greatly appreciated.

You can do this with C# in code behind. Add a OnCheckedChanged event to the CheckBox and set the AutoPostBack to true and handle the change. Note that a Panel becomes a div in HTML.
<asp:CheckBox ID="limitOptions" runat="server" OnCheckedChanged="limitOptions_CheckedChanged" AutoPostBack="true" />
<asp:Panel ID="locationOptions" runat="server" Visible="false">
Radius (KM) <asp:TextBox ID="radius" runat="server" Text="100"></asp:TextBox>
</asp:Panel>
However this causes a PostBack, so just using JavaScript could be a better option.
<asp:CheckBox ID="limitOptions" runat="server" onclick="toggleOptions()" />
<div id="locationOptions" runat="server" style="display: none">
Radius (KM)<asp:TextBox ID="radius" runat="server" Text="100"></asp:TextBox>
</div>
<script type="text/javascript">
function toggleOptions() {
var id = '#<% =locationOptions.ClientID %>';
if ($(id).css('display') == 'none') {
$(id).slideDown('fast', function () { });
} else {
$(id).slideUp('fast', function () { });
}
}
</script>

modal pop up extender

What I'm doing is creating a list of tickets using a ListView. One of the controls in the item template is a link button that shows the header of the ticket. When the user clicks the link button, I want to open a modal window that shows the ticket in readable format. To get the ticket, I'll be passing that page a variable and it'll do the rest; nothing complicated. The page will have 3 buttons and the windows needs to close when you click one of them.
Now, I figured out how to use the ModalPopupExtender from the Ajax tookit more or less. You create the panel in it's own div which stays hidden. I created a click event that basically uses a webclient to download the html from the page and insert it into that div's innerHtml. This seems to work the first time. But as soon as you click a different link, the page pukes and says something about it being in an illegal state.
I'm not sure if I'm going about this wrong, and I can't find any decent examples of how to do this. Well there's one, but the english is hard to understand and it's in VB instead of C#. Any help?

<%# Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="asp" %>
<form id="form1" runat="server">
<div><asp:toolkitscriptmanager id="ToolkitScriptManager1" runat="server"> </asp:toolkitscriptmanager>
<br />
<asp:modalpopupextender dropshadow="true" okcontrolid="btnOk" cancelcontrolid="btnClose" runat="server" popupcontrolid="Panel1" id="ModalPopupExtender1" targetcontrolid="Button1" />
<asp:panel id="Panel1" runat="server" cssclass="modalPopup" style="display: none;"> This is basic modal popup. <br /><br />
<asp:Button ID="btnOk" runat="server" Text="Ok" /> <asp:Button ID="btnClose" runat="server" Text="Close Me" />
<iframe src="http://www.google.com"></iframe>
</asp:panel>
<asp:button id="Button1" runat="server" text="First Modal Popup" />
</div>
</form>

multiple submit buttons won't postback on aspx - only last button

On my aspx page I have two fieldsets, each wrapped with an <asp:Panel DefaultButton="..."> that have their own <input type="submit"> buttons. Here's an abbreviated version...
<div id="content">...</div>
<asp:Panel runat="server" id="formPanel1" DefaultButton="form1SubmitButton">
<fieldset>
<asp:TextBox runat="server" id="textbox1"/>
<asp:TextBox runat="server" id="textbox2"/>
<asp:Button runat="server" id="form1SubmitButton" OnClick="form1SubmitButton_OnClick"/>
</fieldset>
</asp:Panel>
<asp:Panel runat="server" id="formPanel2" DefaultButton="form2SubmitButton">
<fieldset>
<asp:TextBox runat="server" id="textbox3"/>
<asp:TextBox runat="server" id="textbox4"/>
<asp:Button runat="server" id="form2SubmitButton" OnClick="form2SubmitButton_OnClick"/>
</fieldset>
</asp:Panel>
Only the last submit button form2SubmitButton will postback, the other button does nothing when clicked. I have simplified the code above but I should mention that each form, Panel included, is kept in a separate user control that is registered on the aspx.
UPDATE: After some more research I've figured out that the submits are not working because of validators on the another fieldset on the master page. That fieldset is for signing into the site, so it is needed. Thoughts?

As PCasagrande mentioned, make sure your validation groups match the default button and all validators. Specially for your logging part.
Example:
<asp:Panel ID="pnlUpdateInfo" runat="server" DefaultButton="btnUpdateInfo">
<ASP:TEXTBOX id="txtZip" runat="server"></ASP:TEXTBOX>
<asp:RequiredFieldValidator id="reqvalZipSignUp" runat="server"
ControlToValidate="txtZip" ValidationGroup="btnUpdateInfo" />
<asp:Button ID="btnUpdateInfo" runat="server" ValidationGroup="btnUpdateInfo" />
</asp:Panel>

Turns out it has to do with HTML5 constraint validation. I figured this out because in chrome, from the console, I was getting the error An invalid form control with name='...' is not focusable. This led me to this post. I added the html5 attribute formnovalidate="formnovalidate" to the submit buttons and everything works just fine (*tested in chrome v20.0.1132.57, firefox v14.0.1, IE9 v9.0.8112).
So to recap, here's the answer...
<asp:Button runat="server" id="submit1" OnClick="submit1_OnClick" text="Submit" formnovalidate="formnovalidate"/>

Asp.Net popup error message

Is there a way I can display an error message in a popup box? I'm using Asp.Net (C#), and on our webpage, if an order goes throug incorrectly we display an error message. Now, we would like to be able to do so using some sort of pop-up method (maybe Ajax?) - it should be able to take a string value to display the error message.

For a simple approach, you can have a script block that contains alert("your error message"). If you want the popup to be styled as the rest of your website then you could render your error message into a div element and use a jQuery dialog to display it as a modal dialog within your page.

I have used Ajax to accomplish this myself.
Using the ModalPopupExtender and setting the PopupControlID to an Asp Panel, I usually put this into a User Control so it can be easily used through a website.
However below is a snippet of the asp.net code
<div class="modalPopupAlign">
<asp:LinkButton ID="lnkConfirm" Style="display: none;" CausesValidation="false" runat="server" PostBackUrl="#">Confirm</asp:LinkButton>
<ajax:ModalPopupExtender ID="lnkConfirm_ModalPopupExtender" runat="server" TargetControlID="lnkConfirm" PopupControlID="pnlConfirmation" BackgroundCssClass="modalBackground" DropShadow="true" RepositionMode="None">
</ajax:ModalPopupExtender>
<div id="pnlConfirmation" class="modalPopup" style="display: none;">
<br />
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<div class="modalPopupContainerAlign">
<div>
<asp:Image ID="imgIcon" CssClass="modalPopupImage" runat="server" />
<asp:Label ID="lblMessage" CssClass="modalPopupMessage" runat="server"></asp:Label>
<div class="modalPopupTextbox"><asp:TextBox ID="txtValue" Width="200px" MaxLength="100" Visible="false" runat="server"></asp:TextBox></div>
<asp:Button ID="btnAction" runat="server" CausesValidation="false" CssClass="defaultButton" Text="OK" />
</div>
</div>
</ContentTemplate>
</asp:UpdatePanel>
</div>
</div>
It does take some time to get it working properly as I have had a few errors with the script manager, which I currently have setup in a master page.
Just might give you a direction to head for, and the CSS can help shape and colour the message box.
Although this is a complex way in some respect but has many uses.

You can do this with simple javascript like this...
alert("my error message");
Here is more info on using javascript

i want to show or hide some controls in repeater through javascript in c# 3.5

I have a repeater control in which i have loaded questions. I want to display a textbox and a button when some one click the question and answer that question with out posting back the page. the textbox and button get hide when the user post the answer

U could do this with ajax using an UpdatePanel.
The javascript will be generated for you by the ASP.NET engine.
You can learn more on the UpdatePanel here.

<asp:Repeater ID="Repeater1" runat="server">
<ItemTemplate>
<span onclick="ShowTextBox(<%# Container.ItemIndex %>)"><%# Eval("Question") %> </span>
<div style="display:none" id='<%# "dv_"+Container.ItemIndex %>'>
<asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>
<asp:Button ID="Button2" runat="server" Text="Button" />
</div>
</ItemTemplate>
</asp:Repeater>
AND Add some script
`<script type="text/javascript">
function ShowTextBox(index) {
$("#dv_" + index).show();
}
</script>`
Remember you should include the jquery file in the head.
download from jquery.com