Question

I have a foreach loop that loops trought a list of objects. The meaning of it is to set a NavigateUrl to a Hyperlink. My code looks like this:

foreach (var con in contacts)
        {
            if (con.ContactTypeID == 1)
            {
                FacebookIcon.NavigateUrl = "http://facebook.com/" + con.ContactURL;
            }
        }

I wonder if their is some better way to do it. I will have about 10 other ContactTypeID and I rather don’t write nine more if else..

Answer 1

You could use LINQ:

var facebookURL = contacts.Where(c => c.ContactTypeID == 1)
              .Select(c => c.url)
              .FirstOrDefault();
if(facebookURL != null)
    FacebookIcon.NavigateUrl = "http://facebook.com/" + facebookURL;

Edit: Actually you could benefit of LINQ’s deferred execution to reuse the same for every type of contact-type:

var contactType = 1; // facebook
var url = contacts.Where(c => c.ContactTypeID == contactType)
      .Select(c => c.url);
if (url.Any())
    FacebookIcon.NavigateUrl = "http://facebook.com/" + url.First();
contactType = 2;    // google
if (url.Any())
    GoogleIcon.NavigateUrl = "http://Google.com/" + url.First();

Edit 2: Here’s another approach using a Dictionary mapping all types with their URLs which should be more efficient in case you have millions of types 😉 (@MAfifi):

var urlTypeMapping = contacts.GroupBy(c => c.ContactTypeID)
    .ToDictionary(grp => grp.Key, grp => grp.Select(c => c.url));
foreach (var type in urlTypeMapping)
{
    var typeUrl = type.Value.FirstOrDefault();
    if (typeUrl != null)
    {
        switch (type.Key)
        {
            case 1:
                FacebookIcon.NavigateUrl = "http://facebook.com/" + typeUrl;
                break;
            case 2:
                GoogleIcon.NavigateUrl = "http://Google.com/" + typeUrl;
                break;
            default:
                break; //or throw new Exception("Invalid type!");
        }
    }
}