声明不同类型的变量foreach

Question

I'm working with IMAP and POP3 mail in c# and I met a curious problem. The uid (Unique ID) for the two type are different types: for the IMAP is long variable and for the POP is a string. So, the function to download and save the mails are equal except for that. I need to do a foreach loop but the only line that change is the first:

foreach (long uid in uids) //for the imap
foreach (string uid in uids) //for the pop

I can't declare uid first, so, there is a way to duplicate only this line but not the entire function?

Answer 1

Based on your statement of how you'll be using it:

foreach (object uid in uids)
{
    string uidStr = uid.ToString();
    // use uidStr, e.g.
    string myPath = Path.Combine(@"C:\mail\", uidStr);

Or:

foreach (string uid in uids.Select(x => x.ToString()))

Answer 2

Just do

foreach (long uid in uids.OfType<long>())
foreach (string uid in uids.OfType<string>())

(But I don't have enough context from your question to give a more detailed answer.)

[EDIT]

If I take your meaning correctly, you could define your process method like so:

static void process(IEnumerable<string> uids)
{
    foreach (string uid in uids)
    {
        // ...
    }
}

And then call it like this:

process(uids.OfType<int>().Select(uid => uid.ToString()));
process(uids.OfType<string>());

Answer 3

您可以为此使用动态 ：

foreach (dynamic uid in uids)

Answer 4

What happened to the use of var??

foreach (var uid in uids)

?? or have i completely misunderstood the question?