c# String.Join 方法忽略 null 和空字符串

public static string Join(string separator, params object[] values);

var temp = new string[] { "A", null, "B", "C", string.Empty, "D", null, null, "E", "F" };
var ret = String.Join("/", temp);
Console.WriteLine(ret);
//将会输出：A//B/C//D///E/F

var temp = new string[] { "A", null, "B", "C", string.Empty, "D", null, null, "E", "F" };
var ret = String.Join("/", temp.Where(f => !string.IsNullOrWhiteSpace(f)));
Console.WriteLine(ret);
//将会输出：A/B/C/D/E/F

public static string Join(string separator, string[] value)
{
    int s = 0;
    for (var v = 0; v < value.Length; v++)
    {
        string str = value[v];
        if (!string.IsNullOrWhiteSpace(str))
        {
            value[s] = str;
            s++;
        }
    }
    if (s <= 0) return string.Empty;
    var ret = String.Join(separator, value, 0, s);
    return ret;
}