Question

I have the following class:

public class TestClass {
   public IList<TestClassDetail> TestClassDetails {
      get { return _testClassDetails; }
   }
   private List<TestClassDetail> _testClassDetails = new List<TestClassDetail>();

   public TestClass() {
      this._testClassDetails = new List<TestClassDetail>();
   }
}

public class TestClassDetail {
   public TestClassDetail() {
      this.Q = String.Empty;
   }
   public string Q { get; set; }
}


var TestClass a = <some code here to create the instace of a>

Now I need to be able to look at the object a, which in this case has 45 instance of TestClassDetail. I need to check each instance to see the first and only one which has a value of Q that is equal to “xx”. If it’s the 4th instance then I need to return 4.

Is this something that I could do with LINQ?

Answer 1

You can do something like this:

var anonymousType = a.TestClassDetails.Select((item, index) => new { Item = item, Index = index + 1 })
                                      .FirstOrDefault(x => x.Item.Q == "xx");

int indexOfXX = 0;
// If found
if(anonymousType != null)
{
    indexOfXX = anonymousType.Index;
}