C# Razor using statements inconsistently require explicit curly brackets

Question

I have a .NET Framework 4.7.2 web application. I am receiving the following yellow screen error from some of my Views and Partial Views but not all of them:

Expected a "{" but found a "using".
Block statements must be enclosed in "{" and "}".
You cannot use single-statement control-flow statements in CSHTML pages...

Some of the Views and Partial Views within the web application work with streams which need to be disposed. I realize that razor is not the ideal place to work with streams. For now, I am seeking to understand why Razor likes my using statements sometimes but not others.

One of the Views has code like this which works great:

@{
    string baseUrl = "redacted";
    string requestUrl = "redacted";
    ...
    ...

    #region Redacted Region Name
        try
        {
            HttpWebRequest httpWebRequest = WebRequest.Create(requestUrl) as HttpWebRequest;
            httpWebRequest.Method = "GET";

            using (HttpWebResponse response = httpWebRequest.GetResponse() as HttpWebResponse)
            using (var stream = response.GetResponseStream())
            using (var reader = new StreamReader(stream))
            {
                var data = reader.ReadToEnd();
                ...
            }
        }
        catch (Exception ex)
        {
            ...
        }
    #endregion
}

However, a separate view with the following using statement would result in the yellow screen error and Visual Studio complaining about syntax errors:

@{
    string baseUrl = "redacted";
    string requestUrl = "redacted";
    ...
    ...

    HttpWebRequest httpWebRequest = WebRequest.Create(requestUrl) as HttpWebRequest;
    httpWebRequest.Method = "GET";

    using (HttpWebResponse response = httpWebRequest.GetResponse() as HttpWebResponse)
    using (var stream = response.GetResponseStream())
    using (var reader = new StreamReader(stream))
    {
        var data = reader.ReadToEnd();
        ...
    }
}

I know I can just apply explicit curly brackets and my problem will be solved as in the below snippet of code. I'd like to understand why I can't stack the using statements and omit some of the curly brackets in some of my Views. Why does it work sometimes but not others in Razor?:

using (HttpWebResponse response = httpWebRequest.GetResponse() as HttpWebResponse)
{
    using (var stream = response.GetResponseStream())
    {
        using (var reader = new StreamReader(stream))
        {
            var data = reader.ReadToEnd();
            ...
        }
    }
}

score 0 · Answer 1 · answered May 30 '23 at 20:04

The problem appears to be with how Razor decides if I am using a "using statement" or a "using directive" (see https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/using)

using directive: helps with namespaces
using statement: helps dispose of objects that won't get automatically cleaned up by the garbage collector

So far, I have found three ways to communicate to Razor that I want to use the using keyword for a "using statement"

Use curly brackets
Encapsulate the "using statement" within a function or an html helper
Surround the using statements in a #region

I am surprised by the #region solution, but it does seem to work, but you have to be careful not to do anything between the opening of the #region and the scope that contains the usage of the "using statement"

This is ok:

@{
    string baseUrl = "redacted";
    string requestUrl = "redacted";
    ...
    ...

    #region Redacted Region Name
        try
        {
            HttpWebRequest httpWebRequest = WebRequest.Create(requestUrl) as HttpWebRequest;
            httpWebRequest.Method = "GET";

            using (HttpWebResponse response = httpWebRequest.GetResponse() as HttpWebResponse)
            using (var stream = response.GetResponseStream())
            using (var reader = new StreamReader(stream))
            {
                var data = reader.ReadToEnd();
                ...
            }
        }
        catch (Exception ex)
        {
            ...
        }
    #endregion
}

This has syntax errors where Razor believes the using keyword is for a "using directive"

@{
    
    ...
    ...

    #region Redacted Region Name
        string baseUrl = "redacted";
        string requestUrl = "redacted";
        try
        {
            HttpWebRequest httpWebRequest = WebRequest.Create(requestUrl) as HttpWebRequest;
            httpWebRequest.Method = "GET";

            using (HttpWebResponse response = httpWebRequest.GetResponse() as HttpWebResponse)
            using (var stream = response.GetResponseStream())
            using (var reader = new StreamReader(stream))
            {
                var data = reader.ReadToEnd();
                ...
            }
        }
        catch (Exception ex)
        {
            ...
        }
    #endregion
}

C# Razor using statements inconsistently require explicit curly brackets

1 Answers1