Only assignment, call, increment, decrement, await, and new object expressions can be used as a statement

This error might look a little cryptic at first, but what it's basically telling you is that what you typed isn't a valid C# statement. It probably looks really close though, because usually you just have a small typo.

First though, what's a statement? Well, it's every valid line (or in some cases, block) of code that makes up your program, for example:

• Assignments: string name = "my string";
• Calls: MyOtherFunction();
• Increments: x++;
• Decrements: x--;
• Await: await myLongTask;
• New object expressions: new Person();

In general, most statements should either modify a variable's value in-place, perform some side-effect (like a foreach block), or at least do something with the return value.

So if you get this error, double-check the line it's complaining about to make sure it's a valid statement, specifically one of the types listed in the error message itself.

What should you check for?

Are you missing a set of parentheses?
Console.WriteLine

Did you use == instead of =?
string name;
name == Grant;

Did you combine elements of a property and method?
public string Name() { get; set; }

Does your statement only return a value, but you're doing nothing with it?
var hi = "Hello, "; hi + " Grant";

If none of those do it for you, feel free to leave a comment below. Heck, post the offending line, and we'll debug it together - maybe I'll have something else to add to this list.