c# - yield return with try catch，我该如何解决

Question

我有一段代码:

using (StreamReader stream = new StreamReader(file.OpenRead(), Encoding))
{
    char[] buffer = new char[chunksize];
    while (stream.Peek() >= 0)
    {
       int readCount = stream.Read(buffer, 0, chunksize);

       yield return new string(buffer, 0, readCount);
    }
 }

现在我必须用 try-catch block 包围它

try
{
   using (StreamReader stream = new StreamReader(file.OpenRead(), Encoding))
   {
       char[] buffer = new char[chunksize];
       while (stream.Peek() >= 0)
       {
          int readCount = stream.Read(buffer, 0, chunksize);

          yield return new string(buffer, 0, readCount);
       }
    } 
}
catch (Exception ex)
{
    throw ExceptionMapper.Map(ex, file.FullName)
}

我看不出有什么方法可以做我想做的事。

编辑 该方法有签名

public IEnumerable<string> ReadPieces(int pieces)

我需要一个 try catch，在 catch 情况下调用 ExceptionMapper。 该方法由所有调用者延迟使用。

我必须捕获的异常来自这些调用

File.OpenRead()
stream.Read()

Answer 1

这是一个代码片段，对我有用(我没有达到错误条件)。

while (true)
{
    T ret = null;
    try
    {
        if (!enumerator.MoveNext())
        {
            break;
        }
        ret = enumerator.Current;
    }
    catch (Exception ex)
    {
        // handle the exception and end the iteration
        // probably you want it to re-throw it
        break;
    }
    // the yield statement is outside the try catch block
    yield return ret;
}