字符串连接性能

class Program
{
private static readonly string STR = "0123456789";
private static string longSTR = StringList(1024, STR);

static void Main(string[] args)
{
Test(10000, STR);
Test(10, longSTR);
}

public static void Test(int count, string str)
{
for (int i = 2; i <= 1024; i *= 2)
{
Time(string.Format("Nomal  Concat ({0})", i), count, () => Concat(i, str));
Time(string.Format("StringBulider ({0})", i), count, () => StringBulider(i, str));
Time(string.Format("String   List ({0})", i), count, () => StringList(i, str));
Console.WriteLine();
}
}

public static void Time(string name, int count, Func<string> function)
{
var watch = new Stopwatch();
watch.Start();
for (int i = 0; i < count; i++)
{
function();
}
watch.Stop();
Console.WriteLine(name + watch.ElapsedTicks);
watch.Reset();
}

public static string Concat(int count, string str)
{
var result = string.Empty;
for (int i = 0; i < count; i++)
{
result += str + "|";
}
return result;
}

public static string StringBulider(int count, string str)
{
var result = new StringBuilder();
for (int i = 0; i<count; i ++)
{
result.Append(str + "|");
}
return result.ToString();
}

public static string StringList(int count, string str)
{
var result = new List<string>();
for (int i = 0; i < count; i++)
{
result.Add(str);
}
return string.Join("|", result);
}
}