How to disable a particular compiler warning for a particular file

Question

Background

I'm working on a small coding project that is going to be sold to other companies. I needed to create some documentation for it, so I decided to use Sandcastle. After taking far to long to download and install, I finally got it working, and noticed any public method or class that didn't have a comment had red text stating that the comment was missing. I then installed Ghostdoc to help speed up my commenting. This turned on the compiler warnings for missing xml comments, which was great because I now had a list of everything I needed to comment.

The Problem

One of my code files is an auto-generated file, which contains around 3000 compiler warnings. I need to be able to skip that file from creating any "Missing Xml Comment" compiler warnings. I know these things from this post:

• I know I can turn off the compiler warning for the project, but there are other files in the project that should have the compiler warning.
• I know I can use #pragma warning disable 1591 to remove the compiler warning, but the file is autogenerated, and I really don't want to have to re-add it manually every time.
• I know I can add an empty comment, but once again, I really don't want to have to re-add it every time the file gets regenerated.
• I could pull the file out into it's own project since it is the only class in it's namespace, then remove the XML comment requirement, but I don't want the customer to have to deal with another dll.
• The classes are partial classes so I was thinking about trying to find a way to add the #pragma warning disable in a partial class but even if that was possible, there are still enums that would throw warnings.

How can I tell VS to ignore a single file for a particular type of warning?

Answer 1

A couple of possibilities spring to mind:

1. Can you have another class that imports the auto-generated .cs file? The wrapping class has the pragma and just imports the autogenerated class.
2. Write a perl script (or simple C# program) that is called as a build event after the file is generated and before the .cs files are compiled.

Answer 2

If the generated classes should not be visible to your users, you could check if the generation tool has an option to generate the classes as internal rather than public.

If your generated code is a web service reference, you have an option to specify this when you create the reference (in the "Add Service Reference" dialog, Advanced -> Access level for generated classes).

Otherwise, you could try to find a way to change automatically the access level of the types in the generated code from public to internal.

Answer 3

Edit: My Solution

I used David Thielen's suggestion and created a C# program that inserts #pragma warning disable messages into my autogenerated files. Ideally I'd call it as a post operation to the generation of the files themselves, but for now a pre-compile command will suffice since my statement will be one of the first lines in the file, it will only have to read a few lines, see that the disable statement is already there, and quit, so it shouldn't slow down the build. Below is my program for all to enjoy! :)

/// <summary>
/// Addes #pragma warning disable messages to source code as part of a prebuild to ignore warnings.
/// Primarly used for autogenerated classes that may contain some compiler warnings by default
/// </summary>
public class Program
{
    /// <summary>
    /// 
    /// </summary>
    /// <param name="args">
    /// [0] - file to edit
    /// [1] - line number to insert / edit warning disable at
    /// [2+] - warnings numbers to disable</param>
    static void Main(string[] args)
    {
        // Preconditions
        if (args.Length < 2)
        {
            throw new ArgumentException(String.Format("Unexpected number of parameters.{0}Parameters should be [0] - file to edit{0}[1] - line number to insert / edit warning disable at{0}[2+] - warnings numbers to disable", Environment.NewLine));
        }
        else if (args.Length == 2) { return; }

        // Valid number of args, validate arguments
        string filePath = args[0];
        long lineNumber;

        if(!long.TryParse(args[1], out lineNumber)){
            throw new InvalidCastException("Unable to cast \"" + args[1] + "\" to a long");
        }

        string[] compilerWarningNumbers = new string[args.Length - 2];
        Array.ConstrainedCopy(args, 2, compilerWarningNumbers, 0, compilerWarningNumbers.Length);

        // File Name and line number are valid, perform search and replace
        AddOrUpdateCompilerWarningDisabler(filePath, lineNumber, String.Join(",", compilerWarningNumbers));

    }

    private const string TEMP_FILE_POSTFIX = ".CompilerWarningDisabler.txt";
    public static void AddOrUpdateCompilerWarningDisabler(string filePath, long lineNumber, string compilerWarningNumberCSV)
    {
        if (!File.Exists(filePath))
        {
            throw new FileNotFoundException("File path not found!", filePath);
        }

        // Set Clear Readonly Flag
        FileInfo fileInfo = new FileInfo(filePath);
        bool isReadOnly = fileInfo.IsReadOnly;

        // Get Temp File Name and Delete if it already exists
        string tempFile = Path.Combine(Path.GetDirectoryName(filePath), Path.GetFileNameWithoutExtension(filePath) + TEMP_FILE_POSTFIX);
        File.Delete(tempFile);

        // Read from the target file and write to a new file.
        int currentLine = 1;
        string line;
        string textToWrite = "#pragma warning disable " + compilerWarningNumberCSV;
        try
        {
            using (StreamReader reader = new StreamReader(filePath))
            using (StreamWriter writer = new StreamWriter(tempFile))
            {
                while ((line = reader.ReadLine()) != null)
                {
                    if (currentLine == lineNumber)
                    {
                        if (line.StartsWith("#pragma warning disable"))
                        {
                            if (line == textToWrite)
                            {
                                // Nothing has changed, don't bother copying file
                                return;
                            }
                            else
                            {
                                line = textToWrite;
                            }
                        }
                        else
                        {
                            writer.WriteLine(textToWrite);
                            writer.WriteLine(line);
                        }
                    }
                    else
                    {
                        writer.WriteLine(line);
                    }
                    currentLine++;
                }

                if (currentLine == lineNumber)
                {
                    writer.WriteLine(textToWrite);
                }

                if (currentLine < lineNumber)
                {
                    throw new InvalidDataException("File " + filePath + " does not contain line number " + lineNumber);
                }
            }

            // This could potentially delete the source file, but this should be messing with autogenerated files, so even if it does happen, it shouldn't be to hard to get it back
            if (isReadOnly)
            {
                fileInfo.IsReadOnly = false;
            }
            File.Delete(filePath);
            File.Move(tempFile, filePath);
            if (isReadOnly)
            {
                new FileInfo(filePath).IsReadOnly = true;
            }
        }
        finally
        {
            File.Delete(tempFile);
        }
    }
}