Question

I want to clone a generic object and preserve its type.

run.Append(style.Clone(BlackFont)); //run object accepts only RunProperties objects

public T Clone(T what) {
    if (what is RunProperties)
        return (T) what.Clone();
}

It doesn’t work since T type does not have a Clone method, how can I overcome this without casting in the first statement.

run.Append((RunProperties) style.Clone(BlackFont)); //I do not want this
//not that this will work since you can't convert T to RunProperties

Thanks for any help.

—EDIT—

It seems that it would be better for my not to use generics in this case. I’ll split up the data.

Answer 1

You could always constrain the method to only accept types that implement the ICloneable interface:

public T Clone(T what) where T : ICloneable
{
    if (what is RunProperties)
        return (T) what.Clone();
}

But since your method really only works with one type, you could change it slightly and use the as operator also:

public T Clone(T what)
{
    var castWhat = what as RunProperties;
    if(castWhat != null)
        return castWhat.Clone();
}