标志和|=运算符的类型参数约束

不清楚你想得到什么,但是,用一点 Expression 树:

public static class Or<T>
{
    public static readonly Func<T, T, T> Do;

    static Or()
    {
        var par1 = Expression.Parameter(typeof(T));
        var par2 = Expression.Parameter(typeof(T));

        Expression or;

        if (typeof(T).IsEnum)
        {
            Type type = Enum.GetUnderlyingType(typeof(T));
            or = Expression.Convert(
                Expression.Or(
                    Expression.Convert(par1, type), 
                    Expression.Convert(par2, type)), 
                typeof(T));
        }
        else
        {
            or = Expression.Or(par1, par2);
        }

        Do = Expression.Lambda<Func<T, T, T>>(or, par1, par2).Compile();
    }
}

您使用的代码如下:

[Flags]
public enum MyEnum
{
    Val1 = 1,
    Val2 = 2,
    Val3 = 4,
}

public static T OrTogether<T>()
{
    T ret = default(T);

    foreach (T val in (T[])Enum.GetValues(typeof(T)))
    {
        ret = Or<T>.Do(ret, val);
    }

    return ret;
}