Optional C# parameter issue

Question

I have this method ``` public static void WriteErrorLog(LogEntry logEntry, string method, [Optional, DefaultParameterValue(0)] int? errorTypeID) ``` So I expect that I can call the method like ``` WriteErrorLog(l, "text"); ``` But I get an error of Visual Studio anyway :( No overload for method 'WriteErrorLog' takes 2 arguments What I am missing? Thank you!

Accepted Answer

You're not supposed to be using `[Optional, DefaultParameterValue(0)]`. Instead, you should use the c-style default parameter syntax:

```
public static void WriteErrorLog(LogEntry logEntry, string method, int? errorTypeID = 0)
```

Also, if `errorTypeId` is a `Nullable`, then shouldn't you have the default value be `null`?

```
public static void WriteErrorLog(LogEntry logEntry, string method, int? errorTypeID = null)
```

Optional C# parameter issue

Solution

Problem