// C# Extension Method

// Doc: https://csharp-extension.com/en/method/1002775/idatareader-getvaluetoordefault

​

// @nuget: Z.ExtensionMethods

​

using System;

using System.Data;

using System.Data.Common;

using System.Data.SqlClient;

public class Program

{

    public static void Main()

    {

        const string sql = @"SELECT 1 As IntColumn";

        using (var conn = new SqlConnection(FiddleHelper.GetConnectionStringSqlServer()))

        {

            conn.Open();

            using (DbCommand command = conn.CreateCommand())

            {

                command.CommandText = sql;

                using (IDataReader reader = command.ExecuteReader())

                {                   

                    while (reader.Read())

                    {

                        //C# Extension Method: IDataReader - GetValueToOrDefault

                        var result1 = reader.GetValueTo<int>("IntColumn");

                        var result2 = reader.GetValueToOrDefault<int>("UnknownColumn");

                        int result3 = reader.GetValueToOrDefault("UnknownColumn", -1);

                        int result4 = reader.GetValueToOrDefault("UnknownColumn", (dataReader, s) => -2);

​

                        Console.WriteLine(result1);

                        Console.WriteLine(result2);

                        Console.WriteLine(result3);

                        Console.WriteLine(result4);

                    }

                }

            }

        }

    }

}