Error: 'T' must be a non-abstract type with a public parameterless constructor in order to use it as parameter 'T'
c#, generics
Solution
The `T` in the calling code needs to have the same constraints.
Otherwise, someone could call your wrapping function with a `T` that doesn't have a constructor.
Problem
I'm trying to implement a method that takes in a generic T and returns a list of T. ``` public static List<T> GetMessages<T>(string query, int count, SqlConnection sqlconnection) where T : ITable, new() { List<T> messages = new List<T>(); List<T> errorMessages = new List<T>(); DataSet response = DBUtils.ExecuteQueryScriptWithConnection(query, sqlconnection); for (int i = 0; i < response.Tables[0].Rows.Count; ++i) { T message = new T(); DataRow row = response.Tables[0].Rows[i]; message.Id = Convert.ToInt32(row[0]); message.CreatedDate = Convert.ToDateTime(row[1]); } return messages; } ``` But when I call it from another method, I get the error: 'T' must be a non-abstract type with a public parameterless constructor in order to use it as parameter 'T' in the generic type or method '`CIHelpers.TableHelpers.GetMessages<T>(string, int, System.Data.SqlClient.SqlConnection)`' Code that I'm calling this from: ``` List<T> messages = TableHelpers.GetMessages<T>(query, 1000, sqlconnection); ``` The class that implements ITable (type T that I'm passing is here. ``` public class MessageReceived : ITable { public int Id { get; set; } public DateTime CreatedDate { get; set; } string query = String.Format(@"select Id, CreatedDate, from MessageReceived where createddate > '2013-04-18 00:00:00.0000000'"); public MessageReceived() { } } ``` What am I doing wrong?