“is” c# multiple options

Question

return (
      Page is WebAdminPriceRanges ||
      Page is WebAdminRatingQuestions
);

Is there a way to do it like:

return (
    Page is WebAdminPriceRanges || WebAdminRatingQuestions
);

Answer 1

No, such syntax is not possible. The is operator requires 2 operands, the first is an instance of an object and the second is a type.

You could use GetType() :

return new[] { typeof(WebAdminPriceRanges), typeof(WebAdminRatingQuestions) }.Contains(Page.GetType());

Answer 2

Not really. You can look for the Type instance inside a collection, but that doesn't account for the implicit conversions that is performs; for example, is also detects if the type is a base of the instance it operates on.

Example:

var types = new[] {typeof(WebAdminPriceRanges), typeof(WebAdminRatingQuestions)};

// this will return false if Page is e.g. a WebAdminBase
var is1 = types.Any(t => t == Page.GetType());

// while this will return true
var is2 = Page is WebAdminPriceRanges || Page is WebAdminRatingQuestions;

Answer 3

不可以。您指定的第一种方式是唯一合理的方式。

Answer 4

不，C# 不是英语，您不能从两个操作数的操作中省略一个操作数。

Answer 5

No, you can not do this.

if your intent is return a Page, only if it is of type WebAdminPriceRanges or WebAdminRatingQuestions , you can easily do it with if.

For example:

if(Page is WebAdminPriceRanges || Page is WebAdminRatingQuestions)
   return Page;
return null;

Assuming that Page is a reference type or at least nullable value type

Answer 6

The other answers are true, but while I'm not sure where is fits in operator precedence. If the is operator is lower than the logical-or operator, you would be or-ing two classes together which is meaningless.