问题描述
有人可以帮我把这个嵌套结构变成一个 LINQ 语句吗?
can someone please help me turn this nested structure into a single LINQ statement?
EventLog[] logs = EventLog.GetEventLogs();
for (int i = 0; i < logs.Length; i++)
{
if (logs[i].LogDisplayName.Equals("AAA"))
{
for (int j = 0; j < logs[i].Entries.Count; j++)
{
if (logs[i].Entries[j].Source.Equals("BBB"))
{
remoteAccessLogs.Add(logs[i].Entries[j]);
}
}
}
}
推荐答案
嵌套循环通常以多个from"子句结束(编译器将其转换为对 SelectMany 的调用):
Nested loops usually end up with multiple "from" clauses (which are converted into calls to SelectMany by the compiler):
var remoteAccessLogs = from log in EventLogs.GetEventLogs()
where log.LogDisplayName == "AAA"
from entry in log.Entries
where entry.Source == "BBB"
select entry;
(假设 remoteAccessLogs 在此调用之前为空，并且您很乐意直接对其进行迭代 - 如果您想要 ToList()代码>列表<T>.)
(That's assuming that remoteAccessLogs is empty before this call, and that you're happy iterating over it directly - you can call ToList() if you want a List<T>.)
这是点符号的形式:
var remoteAccessLogs = EventLogs.GetEventLogs()
.Where(log => log.LogDisplayName == "AAA")
.SelectMany(log => log.Entries)
.Where(entry => entry.Source == "BBB");
或者列表:
var remoteAccessLogs = EventLogs.GetEventLogs()
.Where(log => log.LogDisplayName == "AAA")
.SelectMany(log => log.Entries)
.Where(entry => entry.Source == "BBB")
.ToList();
请注意，我使用重载的 == 表示字符串，因为我发现它比调用 Equals 方法更容易阅读.两者都可以.
Note that I've used the overloaded == for string as I find it easier to read than calling the Equals method. Either will work though.
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