Mixing in new fields to an object without hard-coding its fields in a LINQ query?

Question

I have a simple LINQ query here:

var Staffs = new[] 
{
    new { id = 1, name = "Jefferson", age = 42},
    new { id = 2, name = "Jacobson", age = 54},
    new { id = 3, name = "Zhang", age = 34}
};

var payroll = new[]
{
    new { pid = 1, wage = 5000},
    new { pid = 2, wage = 6500},
    new { pid = 3, wage = 6700}
};

var q = from stf in Staffs
        from pay in payroll
        where stf.id == pay.pid
        select new
        {
            stfObj = stf,
            pay.pid,
            pay.wage
        };

Here, stfObj would be an object containing the id, name and age fields

Here comes the question:

Is it possible to turn the object into the fields themselves without explicitly hard-coding the field names like this:

select new
{
    stf.id,
    stf.name,
    stf.age,
    pay.pid,
    pay.wage
 };

In this way, there will be no need to change the select new block when I add a new field to Staffs, like Gender for example

Is that possible?

(ok, this looks like the question here... anyway, hoping to get better answers here)

possible duplicate of [How to select all fields plus some new fields in LINQ?](http://stackoverflow.com/questions/10036421/how-to-select-all-fields-plus-some-new-fields-in-linq) — Daniel Hilgarth, Aug 30 '12 at 12:10

score 0 · Answer 1 · answered Aug 30 '12 at 12:12

0

Is this what you want!

select new
{
sId=stfObj.id,
sName=stfObj.name,
sAge=stdObj.age,
pId=pay.pid,
pWage=pay.wage
};

answered Aug 30 '12 at 12:12

Anirudha

32,393
7
68
89

Julien Ch. · Answer 2 · 2012-08-30T12:37:12.283

0

Why not simply embed your object ?

select new {
    staff = stf,
    pay = pay
};

edited Aug 30 '12 at 12:37

answered Aug 30 '12 at 12:16

Julien Ch.

1,231
9
16

score 0 · Answer 3 · answered Aug 31 '12 at 00:05

I do not know, what you need this for. But you could try to use Dictionary<> for this. Say, we have a class:

public class Test
{
    public string Name { get; set; }
    public string Desc { get; set; }    
}

So you can do the following:

List<Test> list = new List<Test>
{
     new Test
     {
         Name = "Test 1",
         Desc = "Desc 1"
     }
};
var temp = list.Select(t =>
                {
                    Dictionary<string, object> values = new Dictionary<string, object>();
                    foreach (PropertyInfo pi in t.GetType().GetProperties())
                        values[pi.Name] = pi.GetValue(t, null);
                    return values;
                })
               .FirstOrDefault();
temp.ToList().ForEach(p => Console.WriteLine(string.Format("{0}:\t{1}", p.Key, p.Value)));

So if you add a property to the Test class, say, like this:

public bool Extra { get; set; }

You'll get it in the dictionary automatically. Probably you'll have to work with reflection methods overloads to get exactly what you need...

Mixing in new fields to an object without hard-coding its fields in a LINQ query?

3 Answers3