C#

OriginalGriff wrote:

the IEnumerable interface which "allows" you to use your class in a foreach statement ... If you don't implement it, the compiler will complain

public struct DuckEnumerator
{
    public bool MoveNext()
    {
        return true;
    }
    
    public string Current
    {
        get { return "Quack!"; }
    }
}

public class Duck
{
    public DuckEnumerator GetEnumerator()
    {
        return new DuckEnumerator();
    }
}

int count = 0;
var donald = new Duck();
foreach (string value in donald)
{
    Console.WriteLine(value);
    if (++count > 42) break;
}

Member 9730878 wrote:

What is benefit of it?

using (SqlConnection con = new SqlConnection("famousstringhere"))
using (SqlCommand cmd = con.CreateCommand())
{
  ..
}

using (IDbConnection con = new SqlConnection("famousstringhere"))
using (IDbCommand cmd = con.CreateCommand())
{
  ..
}

Bastard Programmer from Hell
If you can't read my code, try converting it here[^]

using (DbConnection con = new SqlConnection("..."))
using (DbCommand cmd = con.CreateCommand())
{
    cmd.CommandText = "SELECT 42 As TheAnswer";
    
    await con.OpenAsync();
    int result = (int)(await cmd.ExecuteScalarAsync());
}

Richard Deeming wrote:

Unfortunately, not the best example.

Richard Deeming wrote:

Also, given the huge difference in the syntax used to access different databases / providers, you're unlikely to be able to reuse your database code anyway.

Bastard Programmer from Hell
If you can't read my code, try converting it here[^]

using (var connection = new SqlConnection(con))
using (var command = new SqlCommand("INSERT INTO manage (Signature) VALUES (@Signature)", connection))
{
    byte[] saveInk = (byte[])axInkPicture1.Ink.Save(InkPersistenceFormat.IPF_GIF, InkPersistenceCompressionMode.IPCM_Default);
    command.Parameters.AddWithValue("@Signature", saveInk);
    
    connection.Open();
    command.ExecuteNonQuery();
}

cmdDatabase.Parameters.AddWithValue("@Signature", saveInk);

object reference is not set to the instance of object

char?[] charArray = myString.Cast<char?>().ToArray()