Вставка данных в таблицу на C#

Здесь есть чем заняться. Примечания в виде комментариев для пояснения изменений.

// Do NOT use array elements as fields! Classes (or Records) are so much better for this.
public class PlayerData
{
    public string FirstName {get;set;}
    public string LastName {get;set;}
    public string Race {get;set;}
    public string Class {get;set;}
}
// Again: if a class is this simple, with only basic auto-implemented properties, it should probably be a record.
// I left it as a class because someone new to C# may not have seen records yet.
// Also remember, you'll be able to re-use this class when going the other direction and selecting data back out of the database.

public class Program
{
    public static void Main(string[] args)
    {
        // create our player object closer to where it's used
        var player = new PlayerData();

        // Receives player's first name
        Console.WriteLine("Please enter your character's first name: ");
        player.FirstName = Console.ReadLine();
        Console.Clear();

        // Receives player's last name
        Console.WriteLine("Please enter your character's last name: ");
        player.LastName = Console.ReadLine();
        Console.Clear();

        // Uploads the basic data to table
        DataManager.UpdatePlayerStatistics(player);
    }
}

public class DataManager
{
    // private connection string. 
    // Now other types won't be able to connect on their own (no string).
    // This forces data access to go through your data manager, where it belongs.
    // Some apps may opt to have this set via a constructor, load it 
    // from a config file or similar, or use dependency injection
    private static string connectionString = "connection string here";

    // No longer need to pass connection string as an argument
    // Also, we can accept the PlayerData type, with nice named fields
    public static void UpdatePlayerStatistics(PlayerData player) 
    {
        // this could be *const* if we wanted... it will never change!
        // However, I had to guess at the column names.
        // Also note how I included the parameter variables in the string
        string sql = "INSERT INTO dbo.Players (FirstName, LastName) VALUES (@FirstName, @LastName);";
        using var connection = new SqlConnection(connectionString); 
        using var cmd = new SqlCommand(sql, connection);

        // Do NOT use AddWithValue() (it has a serious performance "gotcha" that can crop up)
        // DO use the exact database column type and size from the database
        cmd.Parameters.Add("@FirstName", SqlDbType.NVarChar, 20).Value = player.FirstName;
        cmd.Parameters.Add("@LastName", SqlDbType.NVarChar, 25).Value = player.LastName;

        connection.Open();
        cmd.ExecuteNonQuery();
        // No need to call .Close() because the using directive takes care of it in a better way
    }
}

я думаю, что самый простой способ:

                 ExampleEntities1 db = new ExampleEntities1();
                 Tbl(your table name) D = new Tbl(your table name)();
                 D.PlayerFirstName = TxtPlayerFirstName.Text;
                 D.PlayerLastName = TxtPlayerLastName.Text;
                 D.PlayerClass = TxtPlayerClass.Text;
                 D.PlayerRace = Convert.ToInt32(PlayerRace.Text);
                 db.Tbl(your table name).Add(D);
                 db.SaveChanges();
                 this.DialogResult = DialogResult.OK;

таким образом вы легко можете добавить свою дату в winform в базу данных.