C#: Create and pass variable straight in the method call

Question

enter code hereI would like to know how to declare new variable straight in the parameter brackets and pass it on like this:

MethodA(new int[]) //but how to fill the array if declared here? E.g. how to declare and set string?


MethodA(int[] Array)
...

and what if need to declare an object (class with constructor parameter)? Still possible within parameter list?

Answer 1

You can try this:

MethodA(new int[] { 1, 2, 3, 4, 5 });

This way you achieve the functionality you asked for.

There seems to be no way to declare a variable inside parameter list; however you can use some usual tricks like calling a method which creates and initializes the variable:

int[] prepareArray(int n)
{
    int[] arr = new int[n];
    for (int i = 0; i < n; i++)
        arr[i] = i;
    return arr;
}

...
MethodA(prepareArray(5));
...

With the strings, why not just use string literal:

MethodB("string value");

?

Answer 2

MethodA(new int[] { 1, 2, 3 }); // Gives an int array pre-populated with 1,2,3

or

MethodA(new int[3]); // Gives an int array with 3 positions

or

MethodA(new int[] {}); // Gives an empty int array

You can do the same with strings, objects, etc:

MethodB(new string[] { "Do", "Ray", "Me" });

MethodC(new object[] { object1, object2, object3 });

If you want to pass a string through to a method, this is how you do it:

MethodD("Some string");

or

string myString = "My string";
MethodD(myString);

UPDATE: If you want to pass a class through to a method, you can do one of the following:

MethodE(new MyClass("Constructor Parameter"));

or

MyClass myClass = new MyClass("Constructor Parameter");
MethodE(myClass );

Answer 3

Either new int[0] or new int {} will work for you. You can also pass in values, as in new int {1, 2, 3}. Works for lists and other collections too.

Answer 4

In your case you would want to declare MethodB(string[] strArray) and call it as MethodB(new string[] {"str1", "str2", "str3" })

P.S. I would recomment that you start with a C# tutorial, for example this one.

Answer 5

Do you simply mean:

MethodA("StringValue"); ??

Answer 6

As a side note: if you add the params keyword, you can simply specify multiple parameters and they will be wrapped into an array automatically:

void PrintNumbers(params int[] nums)
{
    foreach (int num in nums) Console.WriteLine(num.ToString());
}

Which can then be called as:

PrintNumbers(1, 2, 3, 4); // Automatically creates an array.
PrintNumbers(new int[] { 1, 2, 3, 4 });
PrintNumbers(new int[4]);