Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
286 views
in Technique[技术] by (71.8m points)

.net - Finding an item in a List<> using C#

I have a list which contains a collection of objects.

How can I search for an item in this list where object.Property == myValue?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Answer

0 votes
by (71.8m points)

You have a few options:

  1. Using Enumerable.Where:

    list.Where(i => i.Property == value).FirstOrDefault();       // C# 3.0+
    
  2. Using List.Find:

    list.Find(i => i.Property == value);                         // C# 3.0+
    list.Find(delegate(Item i) { return i.Property == value; }); // C# 2.0+
    

Both of these options return default(T) (null for reference types) if no match is found.

As mentioned in the comments below, you should use the appropriate form of comparison for your scenario:

  • == for simple value types or where use of operator overloads are desired
  • object.Equals(a,b) for most scenarios where the type is unknown or comparison has potentially been overridden
  • string.Equals(a,b,StringComparison) for comparing strings
  • object.ReferenceEquals(a,b) for identity comparisons, which are usually the fastest

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...