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C# Errors in ASP.NET

Server Error in '/asppub' Application.
Compilation Error
Description: An error occurred during the compilation of a resource required to service this request. Please review the following specific error details and modify your source code appropriately.
Compiler Error Message: CS1061: 'ASP.mis3200_unit4_ringu4pos_aspx' does not contain a definition for 'rblSnacks_SelectedIndexChanged' and no extension method 'rblSnacks_SelectedIndexChanged' accepting a first argument of type 'ASP.mis3200_unit4_ringu4pos_aspx' could be found (are you missing a using directive or an assembly reference?)
Source Error:
Line 102: Would you like any snacks?</td>
Line 103: <td class="style7">
Line 104: <asp:RadioButtonList ID="rblSnacks" runat="server"
Line 105: RepeatDirection="Horizontal" Width="96px" AutoPostBack="True"
Line 106: onselectedindexchanged="rblSnacks_SelectedIndexChanged">
Source File: c:\Users\Ryan\Desktop\asppub\MIS3200\Unit4\RingU4POS.aspx Line: 104
The given error message in my coding class was this:
Snacks: toggle visiblity based on yes/no selection: -2
The list of snacks should only be visible when somebody selects Yes (otherwise, it should be invisible). You needed to double-click the RadioButtonList to create a method which had functionality to toggle the visibility property of the CheckBoxList. For this method to work, you must enable AutoPostBack for the RadioButtonList. "
What am I doing wrong? Any help would be appreciated.

You have missed this in server side
protected void rblSnacks_SelectedIndexChanged(object sender, EventArgs e)
{
}

Add this code in your code behind
protected void rblSnacks_SelectedIndexChanged(object sender, EventArgs e)
{
// some code
}

You should define a rblSnacks_SelectedIndexChanged method in a code behind that will handle the SelectedIndexChange event for the radio button. And if you do not need it, you should remove it.

As the error suggests, you have to have the SelectedIndexChanged in your code behind. So add this code,
protected void rblSnacks_SelectedIndexChanged(object sender, EventArgs e)
{
//your code;
}

Compiler Error Message: CS0103: The name 'listBox1' does not exist in the current context

I am getting the above error. The error is on line 33, it says.
Here's the code:
Source Error:
Line 31:
Line 32: while(r.Read()) {
Line 33: listBox1.Items.Add(new ListItem(r["first_name"], r["first_name"])); //this is the offending line
Line 34: }
Line 35: con.Close();
Now, I figured my ASP.NET was fine, I have the following code there:
<asp:ListBox ID="listBox1" runat="server">
</asp:ListBox>
What might I be doing incorrectly here? I have the user control setup in the .aspx file, I have the correct item in my .aspx.cs file - it should work, shouldn't it? What am I missing? I'm still new to C#

If you have created a UserControl instance inside your aspx then you have to find the ListBox control inside the UserControl instance using its Controls collection.
Here's a link on MSDN.
Another alternative is to have your individual control handlers inside the code-behind file of the UserControl.

Does your listBox1 control exist inside your designer.cs file? If not, regenerate the auto-generated C# file by deleting it, right clicking the aspx file and clicking on "Convert to Web Application".

how to databind a datalist's page index to a button's commandname?

i got this inside a button inside a datalist
CommandName="<%# Container.ItemIndex %>"
when i click the button, i'm expecting commandname to = 0, then 1, then 2, etc, as the datalist progresses, and i'm using that value in the button click's c#
but i'm getting this error, i'm pretty sure i'm using this exact setup on another page and i have no problems, any idea what's going on?
Server Error in '/' Application.
Compilation Error
Description: An error occurred during the compilation of a resource required to service this request. Please review the following specific error details and modify your source code appropriately.
Compiler Error Message: CS0117: 'System.Web.UI.Control' does not contain a definition for 'ItemIndex'

figured out this will work for some reason, posting for future searchers
CommandName='<%# DataBinder.Eval(Container,"ItemIndex") %>'

C# Button Click

I have the following button on a .aspx page:
<asp:Button runat="server" ID="bntLogin" OnClick="bntLogin_Click" Text="Login" />
With the following in the .aspx.cs:
protected void bntLogin_Click(object sender, EventArgs e)
{
//
}
When I try to build it I get the following error:
'ASP.reserve_aspx' does not contain a definition for 'bntLogin_Click' and no extension method 'bntLogin_Click' accepting a first argument of type 'ASP.reserve_aspx' could be found (are you missing a using directive or an assembly reference?)
However, when I move the click event from the code-behind to a script block inside the markup it builds.
Any ideas?

Are you sure that you placed the method in the correct code-behind file?
Check which file you are using as your code-behind file by looking at the #page directive at the top of the aspx file itself (check the inherits attribute) - you may be surprised.
A loosely-related side note: By setting the OnClick with a string value that corresponds to the method you wish to invoke you are implicitly relying on ASP.NET's AutoEventWireup feature which I don't consider to be a good approach. It is better to manually wire up your controls in your page's OnInit override method like this:
bntLogin.Click += bntLogin_Click;
By relying on AutoEventWireup you are allowing the ASP.NET runtime to create this code for you and since this happens at execution time you are incurring an execution time performance penalty as well as risking an exception like the one you are seeing now.

I usually hook up the events in the code-behind's OnInit method, which is a hold-over from ASP.NET 1.1 (that's where the designer would put it back then.)

If by any chance you're still running ASP.NET 1.1, delete the aspnet_client folder, rebuild and try again.

ASP.net CS1061 Compilation Error on deployment

I'm having a bit of a pain here and I just can't figure out what's wrong.
I have an ASP.net project which I deployed on a server. At first everything seemed allright, no Errors whatsoever. However, as a last adition I wanted to add a search function to a fairly large list so I added the following syntax to my mark-up:
<td>
Search Server:
<asp:TextBox ID="txtSearch" runat="server" />
<asp:Button ID="btnLookup" runat="server" OnClick="btnLookup_Clicked" Text="Search" />
<asp:Label ID="lblFeedback" runat="server" />
</td>
and the following in code behind:
protected void btnLookup_Clicked(object sender, EventArgs e)
{
lblFeedback.Text = "";
Session["IsSearch"] = true;
LoadServerList();
}
When I run this locally it works just fine as I expect.
HOWEVER!
When I copy these files to the server I get a compilation error:
Compiler Error Message: CS1061: ' ASP.ntservice_ reports_ reports_ serverlist_ manage_ aspx ' does not contain a definition for 'btnLookup_ Clicked' and no extension method 'btnLookup_ Clicked' accepting a first argument of type 'ASP.ntservice_ reports_ reports_ serverlist_ manage_ aspx' could be found (are you missing a using directive or an assembly reference?)
it says there is nothing that handles my Clicked event although it does work when I run it through Visual studio.
any ideas?
EDIT:
What I tried myself is
renaming button
deleting and readding the button
add through designer
renaming click event
removing the event from markup allows normal execution ... :/

Is your project a web site or a web application? I would guess that it's a web application project and that perhaps you don't have the latest DLL deployed from the bin folder. Check the versions between your machine and the server to verify that they are the same.

I think this error is generated when you change an object Name, ex.
Text1 -» txtSerialNo I had the same problem but I could fix it. Here is the solution:
Go to Split Mode, click on the textbox/object, in the code remove the line
[**ontextchanged="txtSerialNo_TextChanged"**]
From:
[<asp:TextBox ID="txtSerialNo" runat="server"
ontextchanged="txtSerialNo_TextChanged"></asp:TextBox> //remove this line]
To:
[<asp:TextBox ID="txtSerialNo" runat="server"</asp:TextBox>]
I hope it works for you. Bless you.

I experienced same problem. And I made the event handler method public, problem solved!
Thanks!

Did you deploy the dll?

Do you set
<%# Page ... Language="C#" CodeBehind="... .aspx.cs" Inherits="..." .../>
in your page directive correctly?

This should fix it if you did everything else right:
Try to make an entirely new click event (using the split view, just to be sure you get the method signature right.)
Then copy your code from your previous clicked event into the newly created event, copy the new event's method name to your original button and see if it works.

Try renaming the event handler to some thing OnClick="buttonLookup_Clicked"... and changing the event handler signature to match it.

having the same issue myself, I made the method public so that removed the compiler error, then followed that with including everything within
<form runat="server">
.....
<asp:Button id... OnClick="MethodName"/>
</form>
Hope this helps

Make the events your onclick events point to public.

This can happen if the event is signed-up for programmatically AND also in the markup (via the properties)

go to Build ==> Clean Solution ==> Run (f5)

I just restarted my ASP.NET Development server then its running again.

I experienced the same problem with you, but I fix it by include CodeFile="xxxx.aspx.cs" into my page directive, hope this help.

Right Click on the form which affected and go to properties, change the Build Action to Compile. typically this error comes when the Build Action changed to resource.

In my case this issue occurs when there are two projects in solution, and the second project has reference of first project dll.
When you add new members to the class in first project make sure you build the first project first and then second project will compile successfully