test.test test.test - 2 months ago 20
C# Question

Dapper: how to map columns from table in internal class models?

I have sql table tbl_persons with fields: first_name, last_name, first_name_eng, last_name_eng.

And a Model:

public class PersonName
{
public string FirstName { get; set; }

public string LastName { get; set; }
}

public class Person
{
public PersonName Name { get;set; }

public PersonName NameEng { get;set; }
}


How can I map rows from tbl_persons to Person objects?

Answer

You can use the Multi-Mapping API of Dapper

This should work fine.

var result = new List<Person>();
var q = "SELECT null as S, first_name as FirstName,
                         last_name AS LastName,first_name_eng AS FirstName,
                         last_name_eng AS LastName FROM tbl_persons";
using (var con = new SqlConnection("YourConnStringHere")
{
   result = con.Query<Person, PersonName,PersonName, Person>(q, (p,n,ne) =>
                      { p.Name = n; p.NameEng =ne;  return p; },
             splitOn: "FirstName,FirstName").ToList();
}

Note : You need the null as S as a dummy column even though you are not using it in your class. If you do not provide that, you will get an error with your current class structure (no non-complex type properties)

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