为什么我们应该使用StringBuilder的ToString方法？

Question

MSDN说我们需要将StringBuilder对象转换为string,但StringBuilder工作正常吗？我们为什么要转换？

string[] spellings = { "hi", "hiii", "hiae" };

StringBuilder Builder = new StringBuilder();

int counter = 1;

foreach (string value in spellings)
{
    Builder.AppendFormat("({0}) Which is Right spelling? {1}", counter, value);
    Builder.AppendLine();
    counter++;
}

Console.WriteLine(Builder); // Works Perfectly
//Why should i use tostring like below
Console.WriteLine(Builder.ToString());
// Does it make any difference in above two ways.

Console.ReadLine();

Answer 1

这两个调用使用不同的Console.WriteLine重载:WriteLine(Object)和WriteLine(String).

并且WriteLine(object)重载调用"...调用值的ToString方法以生成其字符串表示,并将结果字符串写入标准输出流." (msdn)

编辑

我能看到的唯一区别是:

StringBuilder sb = null;
Console.WriteLine(sb); // prints terminator
Console.WriteLine(sb.ToString()); // throws NullReferenceException