How to get rid of __o is not announced?

Question

I have a code on my homepage that sets up a hyperlink with some confidential information.

<%If Not IsNothing(Profile.ClientID) Then%> <span class="menu-nav"> <a target="_blank" href= "http://b/x.aspx?ClientID=<%=Profile.ClientID.ToString()%>&Initials=<%=Session("Initials")%>" > Send <br /> SMS <br /> </a> </span> <%End If %> <span class="menu-nav"> <!-- Name __o is not declared Error is flagged here--> 

Now the problem seems to be in the href part. If I delete the dynamic code, the error will disappear. Can someone tell me how to solve this problem?

Answer 1

I found the answer on .net forums. It contains a good explanation of why ASP.Net acts as it is:

Finally, we got reliable reprogramming and identified the main problem. The trivial review is as follows:

  <% if (true) { %> <%=1%> <% } %> <%=2%> 

To provide intellisense in <% =%> blocks during development, ASP.NET generates assignment of a temporary variable __o and language (VB or C #), then provides intellisense for the variable. This is done when the page compiler sees the first block <% = ...%>. But here the block is inside the if, so after closing the if this variable goes out of scope. As a result, we get something like this:

  if (true) { object @__o; @__o = 1; } @__o = 2; 

The workaround is to add a dummy expression on the early page. For example. <% = ""%>. This will do nothing, and it will make sure that __o is declared the top level in the Render method before any potential if statement (or other scoping).

An alternative solution is simple use.

 <% response.write(var) %> 

instead

 <%= var %> 

Answer 2

Yes, I occasionally encountered the same error on pages that use server-side constructs on ASPX pages.

Overtime, I found a fix for it (sorry, I just couldn’t find out where I found this bit of information again), and this fix is ​​to put the following code above errant <%...%> block:

 <%-- For other devs: Do not remove below line. --%> <%="" %> <%-- For other devs: Do not remove above line. --%> 

Apparently where you put the above code, everything matters for VS.NET, so it may take a few attempts to get it right.

Answer 3

This is a strange solution, but for me I was able to fix this problem by simply closing open files with violation in Visual Studio.

With their discovery, I mistakenly got the __o problem.

As soon as I closed them, the __o problem disappeared.

Answer 4

After hours of searching on Google and analyzing the heap of aspx'ses in my current project, it looks like I have found a solution that works for me. I would not advise strongly avoiding html-style comments:

<!-- ... -->

inside an aspx page. Use aspx style comments instead

<%-- ... --%>

In addition, it helped me to get vs intellisense and code highlighting to work again, and mainly - this case started with it - now you can hit breakpoints inside the built-in parts of vb / cs code! And no damn message "This is the wrong location for the breakpoint."

Answer 5

When I cleared the solution, restarted IIS, and it still mysteriously plays out, I believe that sometimes this can be caused by pasting the contents of the ASPX source file from another system into Visual Studio, which “helps” update the code, some identifiers may change, and violation pages.

Paste it into another editor (Notepad ++?), And then save it so that Visual Studio does not "help" and the page works again.