转换为泛型

Question

I have following property in C#:

public T Value
{
    get
    {
        ClassImNotAllowedToChange.GetValue<T>();
    }
    set
    {
        ClassImNotAllowedToChange.SetValue<T>(value);
    }
}

For some reasons I can't change the implementation of ClassImNotAllowedToChange , it may impose some limitations on my part of code. The problem here is that I want to save and read TimeSpan as seconds amount, converted to int . And while I can easily write whatever I want in setter , getter restricts me to use only generic type T , which makes impossible something like this:

get
{
    if (typeof(T) == typeof(TimeSpan))
        return (T)TimeSpan.FromSeconds(ClassImNotAllowedToChange.GetValue<int>());

    return PlcItem.GetValue<T>();
}

There is no implicit conversion from int to TimeSpan , so the first code listing causes an InvalidCastException in runtime. Is there any workaround to convert int to TimeSpan within getter or it's better to find another way of implementation?

Answer 1

As workaround you can cast TimeSpan.FromSeconds to object and then to T (with corresponding performance hit):

get
{
    if (typeof(T) == typeof(TimeSpan))
        return (T)(object)TimeSpan.FromSeconds(ClassImNotAllowedToChange.GetValue<int>());

    return PlcItem.GetValue<T>();
}

But I would recommend to rework your code somehow so you will not need to do this.