问题
I drag and drop a Label control on my ABC.ASPX page.It Compiles correctly.
But the control (Label2) is not available in code-behind ABC.ASPX.cs for value assignment.
What is the resolution?
<%@ Page language="c#" CodeBehind="ABC.aspx.cs" AutoEventWireup="false" %>
<asp:Label ID="Label2" runat="server" Font-Bold="True"></asp:Label>
回答1:
You are probably missing an entry for this in your designer.cs file. You can either add something like this to the file:
protected global::System.Web.UI.WebControls.Label Label2;
Or delete the designer.cs file, right click the parent aspx file and choose "Convert to Web Application". This should recreate the designer.cs file with all the appropriate entries.
回答2:
You might need to add Inherits="XXX.ABC" in your Page Directive, where XXX is your root namespace. Also, I'm assuming that you named your class ABC to coincide with ABC.aspx.cs.
回答3:
Try to remove the control, save the file, add the control again, and again save the file. Problem is probably in your *.designer.cs file, this approach should regenerate it.
回答4:
After creating a user component I wanted to test it in a CalendarTest page. I too could not access the user component through the Code Behind. I did not find a solution on-line, but through trial and error I fixed it with the following steps:
1) in the aspx file, <%@Page... needed "CodeFile=" instead of "Src=" to point to the code behind file
2) in the Code behind aspx.cs file, I needed to replace "public class CalendarTest" with "public partial class CalendarTest"
回答5:
Right Click on the project then select convert to web Application
来源：https://stackoverflow.com/questions/10080906/asp-net-control-not-available-in-codebehind