C# expand array to be arguments-CodePudding

void foo(int one, int two) {
}

public static void Main(string[] args) {
  var bar = new int[] { 1, 2 };
  foo(params bar);
}

What's the correct syntax to deconstruct the bar array and pass it as the arguments to the foo method?

In some other languages you can use a splat operator foo(...bar) or an unpack operator foo(*bar).

How can I do it in C#?

CodePudding user response：

There isn't an equivalent function in C#. Each argument has to be passed individually.

There are, of course, work arounds that you likely already know. You could declare an overload for your function that would accept an array and call the original function using the first two inputs. The other alternative that I can think of is to declare the function parameter with the params keyword so that it could receive an array or multiple conma-separated elements when called.

void foo(params int[] numbers)
{   // TODO: Validate numbers length
    int one = numbers[0];
    int two = numbers[1];
}
public static void Main(string[] args) {
    var bar = new int[] { 1, 2 };
    // both valid function calls below
    foo(bar);
    foo(bar[0], bar[1]);
}

CodePudding user response：

You can always use Reflection for such purpose. Here is example snippet on your example method:

class MainClass
{
    void foo(int one, int two)
    {
        Console.WriteLine(one   two);
    }

    static void Main()
    {
        var myInstance = new MainClass();

        var bar = new object[] { 1, 2 };
        var method = myInstance.GetType().GetMethod(nameof(MainClass.foo), BindingFlags.NonPublic | BindingFlags.Instance)
            ?? throw new InvalidOperationException($"Method '{nameof(MainClass.foo)}' not found");
        method.Invoke(myInstance, bar) ;
    }
}