英文:
Use pattern matching with a C# 7 tuple
问题
以下是已翻译的代码部分：
object foo = ("hello", "world");
if (foo is (string, string) bar) { Console.WriteLine(bar.Item1); }
请注意，我只翻译了代码部分，没有包含问题或其他内容。如果您需要进一步的帮助，请随时提出。
英文:
I have the following code:
object foo = ("hello", "world");
var bar = foo as (string, string)?;
if (bar != null) { Console.WriteLine(bar.Value.Item1); }
Edit: I should say that foo is just an example of a variable I might receive in object form but should be able to convert.
Resharper highlights the 'as (string, string)' and suggests I Use Pattern Matching and when I accept, this is the result:
object foo = ("hello", "world");
if (foo is (string, string) bar) { Console.WriteLine(bar.Item1); }
This looks like it should be ok but it does not compile as (string, string) is highlighted with the error No 'Deconstruct' method with 2 out parameters found for type 'object'
While this code transformation seems like a resharper bug, this is not strictly a resharper-specific question as I'd like to know how should I write this? My original code worked fine but is there a way I can do what my original code is doing with pattern matching?
答案1
得分: 2
抱歉，Resharper使您的代码出现错误。
var bar = foo as (string, string)?; // foo 被强制转换为元组
...
if (foo is (string, string) bar) // 这里没有强制转换，foo 仍然是对象
var foo = ("hello", "world"); // 这里可能是解决方案，重构后的对象会引发错误
英文:
Unfortunately resharper made your code erroneous.
var bar = foo as (string, string)?; // foo casts to tuple
...
if (foo is (string, string) bar) // there is no cast, foo is still object
var foo = ("hello", "world"); // can be a solution here, object causes the error after refactoring
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