Converting C# 8.0 to C# 7.0

Question

I was about to use the below C# code.

await using (var producerClient = new EventHubProducerClient(ConnectionString, EventHubName))
{
    using EventDataBatch eventBatch = await producerClient.CreateBatchAsync();
    eventBatch.TryAdd(new EventData(Encoding.UTF8.GetBytes(eventData)));
    await producerClient.SendAsync(eventBatch);
}

But in build server this is getting failed as the above is C# 8.0 code and build server supports till C# 7.0 code only. Can someone please help me convert the above code from C# 8.0 to C# 7.0 as I couldn't make it work?

Answer 1

In the long run, you're certainly better off updating your build server. You'll need to do that sooner or later anyway.

C# 8.0 has using declarations, which transform this:

using var x = ...;
...

into this:

using (var x = ...)
{
  ...
}

The other C# 8.0 feature in this code is await using, which transforms code like this:

await using (var x = ...)
{
  ...
}

into something similar to this:

var x = ...;
try
{
  ...
}
finally
{
  await x.DisposeAsync();
}

Applying both of these transformations by hand gives you:

var producerClient = new EventHubProducerClient(ConnectionString, EventHubName);
try
{
  using (EventDataBatch eventBatch = await producerClient.CreateBatchAsync())
  {
    eventBatch.TryAdd(new EventData(Encoding.UTF8.GetBytes(eventData)));
    await producerClient.SendAsync(eventBatch);
  }
}
finally
{
  await producerClient.DisposeAsync();
}