CODEWITHSUNDEEP
c#lambda
AdamMc331
AdamMc331

Reputation: 16690

Write a lambda expression to get a list of properties from a list of objects

I have the following two objects:

ProjectPrimitives:
   Name
   ProjectId
   StartDate

ProjectDetails
   ProjectPrimitives
   Description
   Location
   // Other details

In my application I have a List<ProjectDetails> and would like to parse all of the primitives from them to get a List<ProjectPrimitives> using a lambda expression. Effectively, I would like to replace this:

var primList = new List<ProjectPrimitives>();
foreach(ProjectDetails pd in myDetailsList)
{
   primList.add(pd.primitives);
}

I have tried a few things but cannot find the right syntax, if this is in fact possible using lambda statements. One thing I've tried is:

var prims = myList.Where(i => i.primitives).ToList();

But the compiler is expecting a boolean inside the Where() function and I don't know what else to put there.

Upvotes: 2

Views: 5846

Answers (1)

Rhumborl
Rhumborl

Reputation: 16609

If ProjectDetails.primitives is a single ProjectPrimitives, you need Select() to transform the list from ProjectDetails to ProjectPrimitives:

var prims = myList.Select(i => i.primitives).ToList();

If it is a collection, such as List<ProjectPrimitives>, you need SelectMany():

var prims = myList.SelectMany(i => i.primitives).ToList();

Upvotes: 8

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