从try/catch块获得的收益率 [英] Yield return from a try/catch block
本文介绍了从try/catch块获得的收益率的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
As Eric Lippert described in this article, yield return
is not allowed within try/catch
clauses.
有没有一种好方法可以得到这样的东西,而不必手动编写自己的IEnumerator
:
Is there a nice way I could get something like this, without having to write my own IEnumerator
by hand:
public IEnumerable<Data> GetData()
{
var transaction = Session.BeginTransaction());
try
{
IQuery q = CreateQuery(session);
foreach (var result in q.Enumerable())
yield return ProjectResult(result); // <-- doesn't work
session.Commit();
}
catch (Exception ex)
{
transaction.Rollback();
throw;
}
finally
{
transaction.Dispose();
}
}
推荐答案
我只是这样更改事务处理逻辑:
I'd just change the transaction-handling logic like this:
public IEnumerable<Data> GetData()
{
var transaction = Session.BeginTransaction();
bool rollback = true;
try
{
IQuery q = CreateQuery(session);
foreach (var result in q.Enumerable())
{
yield return ProjectResult(result);
}
rollback = false;
session.Commit();
}
finally
{
if (rollback)
{
transaction.Rollback();
}
transaction.Dispose();
}
}
或者,如果您的事务支持处置意味着回滚,除非提交"的想法:
Or if your transaction supports the idea of "dispose means rollback unless it's commited":
public IEnumerable<Data> GetData()
{
using (var transaction = Session.BeginTransaction();
{
IQuery q = CreateQuery(session);
foreach (var result in q.Enumerable())
{
yield return ProjectResult(result);
}
// Commits the tnrasaction, so disposing it won't roll it back.
session.Commit();
}
}
这篇关于从try/catch块获得的收益率的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
查看全文