扩展Task类时，必须在非通用静态类中定义扩展方法

Question

I'm trying to extend Task class, but I get two different errors depending how I extend it: first one:

public class ExtTask : Task
{
    public static void DoSomenthing(this Task task)
    {
        //some code
    }
}

Extension method must be defined in a non-generic static class

so I add static:

public static class ExtTask : Task
{
    public static void DoSomenthing(this Task task)
    {
        //some code
    }
}

getting error:

Static class 'DownloadFile.ExtTask' cannot derive from type 'System.Threading.Tasks.Task'. Static classes must derive from object.

how can I solve this problem?

Answer 1

You don't need to derive from task if you are trying to add an extension method, change it to

public static class ExtTask
{
    public static void DoSomenthing(this Task task)
    {
        //some code
    }
}