使用Linq选择Id（s）

Question

I have a DynamicNode named products which has product name and product id. I need to select all products id's to a array from the DynamicNode products using LINQ.

I tried something like

 @helper PrintProductYearChart(IEnumerable<DynamicNode> products)
{

    var res = products.select(x => x.filelds['Id']).ToAarray();
}

but its not working correctly.

Can any one help.Thanks in advance

Answer 1

The Select LINQ operator Projects each element of a sequence into a new form. what you are you doing will project only one element with 'Id' as index so it will return one element only not an array of Id's

here you should specifiy that you want the ID

   @helper PrintProductYearChart(IEnumerable<DynamicNode> products)
    {

        var res = products.select(x => x.Id).ToArray();
    }

Answer 2

class Program
{
    static void Main(string[] args)
    {
        var collection = new List<DynamicNode>(){
            new DynamicNode { Id = "1", Name = "name1"},
            new DynamicNode { Id = "2", Name = "name2"}
        };

        //Getting Ids using extension methods and lambda expressions
        string[] Ids = collection.Select(x => x.Id).ToArray();

        foreach (string id in Ids)
            Console.WriteLine(id);

        //Gettings ids using linq expression
        var linqIds = from s in collection
                           select s.Id;
        string[] lIds = linqIds.ToArray();

        foreach (string id in lIds)
            Console.WriteLine(id);

        Console.Read();
    }
}

class DynamicNode
{
    public string Id { get; set;}
    public string Name { get; set; }
}