C# ADO.NET: nulls and DbNull — is there more efficient syntax?

Question

I\'ve got a DateTime? that I\'m trying to insert into a field using a DbParameter. I\'m creating the parameter like so:

DbParameter         


        

Answer 1

If you're using C# 3.0 you can create an extension method to do this easy:

public static class DBNullableExtensions
{
    public static object ToDBValue<T>(this Nullable<T> value) where T:struct
    { 
        return value.HasValue ? (object)value.Value : DBNull.Value;
    }
}


class Program
{
    static void Main(string[] args)
    {
        int? x = null;

        Console.WriteLine(  x.ToDBValue() == DBNull.Value );
    }
}

Answer 2

If you are using SQLServer, the System.Data.SqlTypes namespace contains some utility classes that avoid the annoying type casting. For example instead of this:

var val = (object) "abc" ?? DBNull.Value;

you can write this:

var val = "abc" ?? SqlString.Null;

Answer 3

Ah ha! I found an even more efficient solution than @Trebz's!

datePrm.Value = nullableDate ?? (object)DBNull.Value;

Answer 4

The way that I do it, is I have a static utility class that just goes through and checks to see if the parameter value is null, then i set the value to do DBNull. I just do that before i call the Execute.

Answer 5

It would work if you used

datePrm.Value = nullableDate.HasValue ? (object)nullableDate.Value : DBNull.Value;

Answer 6

I think the error with your second attempt is due to nullableDate.Value and DBNull.Value being different types and the ternary operator needing to pick one type to return in both cases. I don't have the environment to test this but I think this should work for you:

datePrm.Value = nullableDate.HasValue ? (object)nullableDate.Value : (object)DBNull.Value;