Fill aggregate class from dataTable using Linq C #

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How to fill an aggregate class in C #?

C#

//Class
public class Employee
{
    public string Name { get; set; }
    public string Department { get; set; }
    public double Salary { get; set; }
    public List<client> client = new <list><client>();

    Public Employee(Client objClient)
    {
        this.client.Add(objClient);
    }
}

public class Client
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string Country { get; set; }
    public string Address { get; set; }
}

//In form a Select returning a DataTable
 var ds= cnn.ExecutarSelectDataSet("select e.Name, e.Department, e.Salary,e.fk_client,c.Id, c.Name,c.Country,c.Anddess" +
                                  "from Employee e" +
                                  "INNER JOIN Client c" +
                                  "ON e.fk_client = c.id");

//I am unable to fill the List <client> Property client Class Employees
List<employee> linqquery = (from dr in ds.Tables["Employee"].AsEnumerable()
    join dr2 in ds.Tables["Client"].AsEnumerable()
    on dr.Field<guid>("fk_client") equals dr2.Field<guid>("id")
     select dr).ToList();

Posted 18-May-15 16:13pm

Thyago Analista

Updated 20-May-15 16:13pm

v5

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Comments

Sergey Alexandrovich Kryukov 18-May-15 23:19pm

What does it mean, "fill a class"? Fill where, with what?
—SA

Thyago Analista 19-May-15 21:13pm

Basically I would like to fill a property which is of type list using LINQ possible?

If as in my example above I'm using an aggregate class.

StM0n 19-May-15 0:22am

Could you please reformat your code?

Thyago Analista 20-May-15 12:05pm

So have a method that returns a DataTable, I would fill this List <oderdetails> Class Order, ie, bringing a collection of OrderDetails. For example in my'm using SQL "SELECT O.Id, O.date, O.person, O.value, D. * FROM INNER JOIN Order ON OrderDetails O.id = D.fk_Order," how do I move the data to the OrderDetails collection Class Order?

Tomas Takac 19-May-15 2:47am

1) You are selecting data rows not entities. The entities need to be created somehow. Use proper ORM! Why to load data into datasets and then hydrate your entities manually? BTW don't you see you are doing the same join twice here?

2) Your Employee class has collection of Clients which implies one employee to many clients relationship. Yet in database it's the employee table holding the FK to client which implies reverse, one client to many employees, relationship. Which one is it then?

3) Your linq query implies ids are guids but your Client entity declares Id as integer.

Thyago Analista 19-May-15 21:17pm

Really thought about using the Entity Framework Context mode, but I'm using a project structure for procedures already pre parameterized.

Tomas Takac 20-May-15 5:12am

But there is no SP! Just one SQL query. Which makes me ask how that one resultset can populate two tables in a dataset? Really, do yourself a favor and use EF. Or any other ORM for that matter.

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vinayvraman · Answer 1 · 2015-05-21T23:57:00

I second what Tomas Takac is saying. I do not understand the necessity to do join once in the sql query and then again in linq. Why not get the joined data directly from sql?

But if you are looking at code to convert datatable to List<employee>, then create a new object of employee class and set the property values from the datarow.

E.g.

C#

// In your linq query replace the select dr to something like the below mentioned code
select new Employee
{
 Name = dr.Field<string>("name"),
 Department = dr.Field<string>("department")
 ...
}; 
</string></string>