这将确保标记方法中的任何异常不会导致异常中断.

很好的解释它here …

This is an attribute that you put against a method to tell the debugger “Nothing to do with me guv’. Ain’t my code!”. The gullible debugger will believe you,and won’t break in that method: using the attribute makes the debugger skip the method altogether,even when you’re stepping through code; exceptions that occur,and are then caught within the method won’t break into the debugger. It will treat it as if it were a call to a Framework assembly,and should an exception go unhandled,it will be reported one level up the call stack,in the code that called the method.

代码示例：

public class Foo
{
    [DebuggerNonUserCode]
    public void MethodThatThrowsException()
    {
        ...
    {
}