How to select data into List<T> instead of DataTable?

问题

This is how currently I'm selecting data from database:

public DataTable GetData()
{
    DataTable table = new DataTable("Table");
    using (SqlConnection connection = new SqlConnection("Connection string"))
    {
        SqlCommand command = new SqlCommand();
        command.Connection = connection;
        command.CommandType = System.Data.CommandType.Text;
        command.CommandText = "query string";

        connection.Open();
        SqlDataAdapter adapter = new SqlDataAdapter(command);
        adapter.Fill(table);
    }
    return table;
}

But it return DataTable and I want to select List instead of DataTable. Like this:

public List<MyClass> GetData()
{
    DataTable table = new DataTable("Table");
    using (SqlConnection connection = new SqlConnection("Connection string"))
    {
        SqlCommand command = new SqlCommand();
        command.Connection = connection;
        command.CommandType = System.Data.CommandType.Text;
        command.CommandText = "query string";

        connection.Open();
        SqlDataAdapter adapter = new SqlDataAdapter(command);
        adapter.Fill(table);
    }
    ...
    return [List of MyClass];
}

How can I do this?

Thanks!

回答1:

I'd recommend you to use dapper-dot-net, if you do not want to dig into LINQ to SQL or Entity Framework. Fumbling around yourself with IDataReader to materialise your result isn't worth the effort in most cases.

回答2:

If you want to use the DataRowCollection to populate a list of custom objects, you could use LINQ and an object initializer:

var lst = table.AsEnumerable().Select(r =>
    new MyObject
    {
        FirstProperty = r.Field<int>("FirstProperty"),
        OtherProperty = r.Field<string>("OtherProperty")
    }).ToList(); 

回答3:

Try this code.

public List<MyClass> GetData()
{
    DataTable table = new DataTable("Table");
    using (SqlConnection connection = new SqlConnection("Connection string"))
    {
        SqlCommand command = new SqlCommand();
        command.Connection = connection;
        command.CommandType = System.Data.CommandType.Text;
        command.CommandText = "query string";
        connection.Open();
        SqlDataAdapter adapter = new SqlDataAdapter(command);
        adapter.Fill(table);
        List<MyClass> list=new List<MyClass>();
        foreach(DataRow row in table)
        {
            MyClass instance = new MyClass();
            instance.ID = row["ID"];
            //similarly for rest of the properties

            list.Add(instance);
        }

    }

    return list;
}

回答4:

If you are using the ADO.NET approach - you'll get back a data Table and you can convert it to a List or IEnumberable.

Alternatively, you could look into ORM tools like nHibernate or use LINQ to SQL

来源：https://stackoverflow.com/questions/10505733/how-to-select-data-into-listt-instead-of-datatable