Swallow Exceptions

A C# Fody plugin that allows you to annotate a method with the [SwallowExceptions] attribute to have the method contents wrapped in a try / catch block.

Introduction to Fody

Nuget

• SwallowExceptions package https://www.nuget.org/packages/SwallowExceptions.Fody

  PM> Install-Package SwallowExceptions.Fody

Your Code

public class MyClass
{
    [SwallowExceptions]
    void MyMethod()
    {
      DoSomethingDangerous();
    }
}

What gets compiled

public class MyClass
{
    void MyMethod()
    {
      try
      {
        DoSomethingDangerous();
      }
      catch (Exception exception)
      {
      
      }
    }
}

Working alongside other Fody Plugins

In the case of other attribute based Fody plugins, i.e. Anotar, the order that the plugins get invoked becomes important.

In most cases you'd like this plugin to be the last plugin to inject code into a method, to do so ensure that it is the last plugin listed in the project's FodyWeavers.xml file like shown here:

<?xml version="1.0" encoding="utf-8"?>
<Weavers>
  <Anotar.Log4Net />
  <SwallowExceptions />
</Weavers>

In this case, you can do things like the following, where Anotar will log the exception, then SwallowExceptions will catch the rethrown exception:

public class MyClass
{
    [LogToFatalOnException, SwallowExceptions]
    void MyMethod()
    {
      DoSomethingDangerous();
    }
}

What gets compiled

public class MyClass
{
    void MyMethod()
    {
      try
      {
        try
        {
            DoSomethingDangerous();
        }
        catch (Exception exception)
        {
            if (logger.IsErrorEnabled)
            {
                var message = string.Format("Exception occurred in SimpleClass.MyMethod. param1 '{0}', param2 '{1}'", param1, param2);
                logger.ErrorException(message, exception);
            }
            throw;
        }
      }
      catch (Exception exception)
      {
      
      }
    }
}

This is a simple solution used to illustrate how to write a Fody addin.

Usage

See also Fody usage.

NuGet installation

Install the BasicFodyAddin.Fody NuGet package and update the Fody NuGet package:

PM> Install-Package Fody
PM> Install-Package BasicFodyAddin.Fody

The Install-Package Fody is required since NuGet always defaults to the oldest, and most buggy, version of any dependency.

Add to FodyWeavers.xml

Add <BasicFodyAddin/> to FodyWeavers.xml

<Weavers>
  <BasicFodyAddin/>
</Weavers>

The moving parts

See writing an addin

Updating Package Version Number

Edit the value in the Version element of Directory.Build.props

Creating the NuGet Package

Run the following command in ./SwallowExceptions/

dotnet pack .\SwallowExceptions.csproj -c Release

The NuGet package will be saved as ./nugets/SwallowExceptions.Fody.(VersionNumber).nupkg

Icon

Lego designed by Timur Zima from The Noun Project.