Can I create an anonymous type collection from a DataReader?

Question

I have this code:

var query = \"SELECT * FROM Cats\";

var conn = new SqlConnection(sqlConnectionString);

conn.Open();

var cmd = new SqlCommand(query);
var rea         


        

Answer 1

Here is an example of doing it with dynamic (which I think is easier to work with) but some may feel does not adhere to the letter of your question.

Call it like this:

var result = SelectIntoList("SELECT * FROM Cats",sqlconnectionString);

You could (like I did) put it into a static class in a separate file for easier maintanence.

public static IEnumerable SelectIntoList(string SQLselect, string connectionString, CommandType cType = CommandType.Text)
{
  using (SqlConnection conn = new SqlConnection(connectionString))
  {
    using (SqlCommand cmd = conn.CreateCommand())
    {
      cmd.CommandType = cType;
      cmd.CommandText = SQLselect;

      conn.Open();

      using (SqlDataReader reader = cmd.ExecuteReader())
      {

        if (reader.Read())  // read the first one to get the columns collection
        {
          var cols = reader.GetSchemaTable()
                       .Rows
                       .OfType()
                       .Select(r => r["ColumnName"]);

          do
          {
            dynamic t = new System.Dynamic.ExpandoObject();

            foreach (string col in cols)
            {
              ((IDictionary)t)[col] = reader[col];
            }

            yield return t;
          } while (reader.Read());
        }
      }

      conn.Close();
    }
  }
}