如何显式丢弃out参数？

本文介绍了如何显式丢弃out参数？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我正在拨打电话：

myResult = MakeMyCall(inputParams, out messages);

但我实际上并不关心消息。如果它是输入参数，我不在乎，我只是传入一个null。如果这是回报，我不在乎，就别管它了。

but I don't actually care about the messages. If it was an input parameter I didn't care about I'd just pass in a null. If it was the return I didn't care about I'd just leave it off.

是否可以用out做类似的事情，还是需要声明一个变量，然后将其忽略？

Is there a way to do something similar with an out, or do I need to declare a variable that I will then ignore?

推荐答案

从C＃7.0开始，可以避免预先声明参数并忽略它们。

Starting with C# 7.0, it is possible to avoid predeclaring out parameters as well as ignoring them.

public void PrintCoordinates(Point p) { p.GetCoordinates(out int x, out int y); WriteLine($"({x}, {y})"); } public void PrintXCoordinate(Point p) { p.GetCoordinates(out int x, out _); // I only care about x WriteLine($"{x}"); }

来源： blogs.msdn.microsoft/dotnet/2017/03/09/ new-features-in-c-7-0 /