Generate a Random Number and a Random String in C#

// needs: using System; using System.Linq;
public static string GetRandomString(int length, bool includeAlphabet = true, bool includeNumbers = true,
                                     bool includeSpecialChar = false, bool capsOnly = false)
{
    Random ran = new Random();

    string chars = "";
    if (includeAlphabet)
        chars += "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
    if (includeNumbers)
        chars += "1234567890";
    if (includeSpecialChar)
        chars += "!@#$%^&*()_";

    string random = "";

    for (int i = 0; i < length; i++)
    {
        int a = ran.Next(chars.Length);
        random = random + chars.ElementAt(a);
    }

    return capsOnly ? random.ToUpper() : random;
}