Casting vs Converting an object toString, when object really is a string

Question

This isn\'t really an issue, however I am curious. When I save a string in lets say an DataRow, it is cast to Object. When I want to use it, I have to cast it ToString. As f

Answer 1

If you know it is a String then by all means cast it to a String. Casting your object is going to be faster than calling a virtual method.

Edit: Here are the results of some benchmarking:

============ Casting vs. virtual method ============
cast 29.884 1.00
tos  33.734 1.13

I used Jon Skeet's BenchmarkHelper like this:

using System;
using BenchmarkHelper;

class Program
{
    static void Main()
    {
        Object input = "Foo";
        String output = "Foo";

        var results 
           = TestSuite.Create("Casting vs. virtual method", input, output)
            .Add(cast)
            .Add(tos)
            .RunTests()
            .ScaleByBest(ScalingMode.VaryDuration);

        results.Display(ResultColumns.NameAndDuration | ResultColumns.Score,
                results.FindBest());
    }

    static String cast(Object o)
    {
        return (String)o;
    }

    static String tos(Object o)
    {
        return o.ToString();
    }
}

So it appears that casting is in fact slightly faster than calling ToString().