C# Programming/Keywords/is

The is keyword compares an object to a type, and if they're the same or of the same "kind" (the object inherits the type), returns true . The keyword is therefore used to check for type compatibility, usually before casting (converting) a source type to a destination type in order to ensure that won't cause a type-cast exception to be thrown. Using is on a null variable always returns false .

This code snippet shows a sample usage:

System.IO.StreamReaderreader=newStreamReader("readme.txt");
boolb=readerisSystem.IO.TextReader;
// b is now set to true, because StreamReader inherits TextReader

C# Keywords
`abstract` `as` `base` `bool` `break` `byte` `case` `catch` `char` `checked` `class` `const` `continue` `decimal` `default` `delegate` `do` `double` `else` `enum` `event` `explicit` `extern` `false` `finally` `fixed` `float` `for` `foreach` `goto` `if` `implicit` `in` `int` `interface` `internal` `is` `lock` `long` `namespace` `new` `null` `object` `operator` `out` `override` `params` `private` `protected` `public` `readonly` `ref` `return` `sbyte` `sealed` `short` `sizeof` `stackalloc` `static` `string` `struct` `switch` `this` `throw` `true` `try` `typeof` `uint` `ulong` `unchecked` `unsafe` `ushort` `using` `var` `virtual` `void` `volatile` `while`
Special C# Identifiers (Contextual Keywords)
`add` `alias` `async` `await` `dynamic` `get` `global` `nameof` `partial` `remove` `set` `value` `when` `where` `yield`
Contextual Keywords (Used in Queries)
`ascending` `by` `descending` `equals` `from` `group` `in` `into` `join` `let` `on` `orderby` `select` `where`

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