Array as a parameter implicit conversion

Question

Initializing an array is ok in these 3 cases

string[] To = { "[email protected]", "[email protected]" };
string[] To = new[] { "[email protected]", "[email protected]" };
string[] To = new string[] { "[email protected]", "[email protected]" };

But when using it as a parameter the first option is not valid so this is valid

MethodWithAnArrayParam(new string[] { "[email protected]", "[email protected]" });
MethodWithAnArrayParam(new [] { "[email protected]", "[email protected]" });

This gives an error

   MethodWithAnArrayParam({ "[email protected]", "[email protected]" });

Why?

What makes you think its invalid? What is the method signature for `.Send()`? — maccettura, Mar 23 '18 at 20:27
Because `{ "[email protected]", "[email protected]" }` is not a valid C# array initializer. You need to tell C# which collection to build, array is not the default collection type — vc 74, Mar 23 '18 at 20:29
Possible duplicate of [Initializing a string array in a method call as a parameter in C#](https://stackoverflow.com/questions/1416500/initializing-a-string-array-in-a-method-call-as-a-parameter-in-c-sharp) — UnholySheep, Mar 23 '18 at 20:29
Possible duplicate of [Can't use an “inline” array in c#?](https://stackoverflow.com/questions/30509177/cant-use-an-inline-array-in-c) — TVOHM, Mar 23 '18 at 20:29
Because this is how the c# language defines an array literal. Just the curly brackets don't define an array literal. https://stackoverflow.com/questions/10921844/how-to-return-an-array-literal-in-c-sharp — oliver, Mar 23 '18 at 20:31
@Servy: okay, maybe not by strict definition of the language standard... but in a more casual sense meaning a character sequence that translates to an initial value of a data structure — oliver, Mar 23 '18 at 20:42
@oliver The term for that is a constructor, or potentially an initializer. A literal is a *value* of an object that is known at compile time. There are only a few types that have meaningful literals, just strings and numeric types (and also `null` and `default(...)`). — Servy, Mar 23 '18 at 20:46

LeviTheOne · Answer 1 · 2018-04-09T07:47:46.823

2

Try using:

new[]{ "[email protected]", "[email protected]" }

Edit: Or you can use

new string[]{ "[email protected]", "[email protected]" }

See: Implicit Typed Arrays

edited Apr 09 '18 at 07:47

answered Mar 23 '18 at 20:29

LeviTheOne

105
9

score 2 · Accepted Answer · edited Mar 23 '18 at 21:09

Arrangement declarations are made using the keyword new

Try this

string TO = new string[]{ "[email protected]", "[email protected]" };

Also you can make use of generic arrays

var TO = new[]{ "[email protected]", "[email protected]" };

The data type of the same is given automatically automatic according to the value given:

new [] { "Hello "," World "} string array
new [] {0, 1, 2} int array
...

All this is invalid because at no time you tell the compiler that it is an Array, since {} has several different uses

emailProvider.Send("hello", { "[email protected]", "[email protected]" }, null, "subject");

emailProvider.Send("hello", (new string[] { "[email protected]", "[email protected]" }), null, "subject");

You can not create a statement without shadow and unassigned in the place of a parameter

bool Send(string message, string[] to, string[] bccTo, string subject);

Array as a parameter implicit conversion

2 Answers2