Question

I have already developed an application which returns DataTable everywhere.

Now my client wants to convert (use some part using service stack), so I need to return DTO (objects) in my application.

I don’t want to change my existing stored procedures or even not want to use LINQ as much as possible (I am not too much aware with LINQ).

For small functionality, I can use Linq no issue.

My question is: how can I change my DataTable to objects of that class?

The sample code is below:

string s = DateTime.Now.ToString();
DataTable dt = new DataTable();

dt.Columns.Add("id");
dt.Columns.Add("name");

for (int i = 0; i < 5000000; i++)
{
    DataRow dr = dt.NewRow();
    dr["id"] = i.ToString();
    dr["name"] = "name" + i.ToString();
    dt.Rows.Add(dr);

    dt.AcceptChanges();
}

List<Class1> clslist = new List<Class1>();

for (int i = 0; i < dt.Rows.Count; i++)
{
    Class1 cls = new Class1();
    cls.id = dt.Rows[i]["id"].ToString();
    cls.name = dt.Rows[i]["name"].ToString();
    clslist.Add(cls);
}

Response.Write(s);
Response.Write("<br>");
Response.Write(DateTime.Now.ToString());

I know, the above method is time-consuming, and I am trying to find an alternate solution.

Is there any alternative way (I guess, LINQ to DataTable) by which it directly converts the rows of tables to List<Class1>?

So that I can return objects in my service stack and go ahead.

Answer 1

Initialize DataTable:

DataTable dt = new DataTable(); 
dt.Columns.Add("id", typeof(String)); 
dt.Columns.Add("name", typeof(String)); 
for (int i = 0; i < 5; i++)
{
    string index = i.ToString();
    dt.Rows.Add(new object[] { index, "name" + index });
}

Query itself:

IList<Class1> items = dt.AsEnumerable().Select(row => 
    new Class1
        {
            id = row.Field<string>("id"),
            name = row.Field<string>("name")
        }).ToList();