Why there are the same variables of mine with a ':' in Visual Studio auto complete list?

Question

What's the difference between myVar and myVar: in VS auto-complete list while working with functions. Why the second one is added to this list ?

Answer 1

C# 4.0 introduced named arguments . This feature allows you to identify method arguments by their names instead of their position:

public void Foo(int bar, string quux)
{
}

// Before C# 4.0:
Foo(42, "text");

// After C# 4.0:
Foo(bar: 42, quux: "text");

// Or, equivalently:
Foo(quux: "text", bar: 42);

Intellisense has been updated to support that feature, that's why its autocompletion mechanism now offers both choices when a symbol accessible from the current scope has the same name as a method argument.

Answer 2

This is probably when you're setting a value for a parameter when calling a method, yeah? In C# .NET 4, you can set named parameters when calling a method. This removes the need for having to enter your parameters in a set order.

private void MyMethod(int width, int height){
   // do stuff
}

//These are all the same:
MyMethod(10,12);
MyMethod(width: 10, height: 12);
MyMethod(heigh: 12, width: 12);

Answer 3

this is a very cool feature. it allows your code to be more tolerant to parameter ordering changes...

Answer 4

In addition to what the others wrote: The first one is a (local) variable or field, while the last one is the name of the parameter of the called method. In code:

private void MyFirstMethod(int myVar)
{
    Console.WriteLine(myVar);
}

private void MySecondMethod(int myVar)
{
    MyFirstMethod(myVar); // Call with the value of the parameter myVar
    MyFirstMethod(myVar: myVar); // Same as before, but explicitly naming the parameter

    MyFirstMethod(5); // Call with the value 5
    MyFirstMethod(myVar: 5); // Same as before, but explicitly naming the parameter
}