Question

For example. I have folder “MyFolder”
And I want to get the size of all files that file name is “*D.*“

Is there a easy way to do this?

(P.S. I know for whole folder, I can use TotalSize() to get its size, but how about with my constraints?)

Answer 1

Is there a easy way to do this?

Yes, there is. A single line of code actually:

using System;
using System.IO;
using System.Linq;

class Program
{
    static void Main()
    {
        long size = Directory
            .EnumerateFiles(@"c:\work", "*d.*")
            .Select(x => new FileInfo(x))
            .Sum(x => x.Length);
        Console.WriteLine(@"The size of files in c:\work\*d.* is {0} bytes", size);
    }
}

And if you are targeting a .NET version prior to .NET 4.0 where the EnumerateFiles method is not available you could use the GetFiles method instead.