Question

我有一个自定义排序，我用它来排序一个工作正常的列表

public static void Sort<T>(ref List<T> list, string propertyName, SortDirection direction)
{
    var comparer = new CustomComparer();
    list = direction == SortDirection.Ascending
        ? list.OrderBy(x => x.GetType().GetProperty(propertyName).GetValue(x, null)).ToList()
        : list.OrderByDescending(x => x.GetType().GetProperty(propertyName).GetValue(x, null)).ToList();
}

现在我尝试在混合中添加CustomComparer，并在扩展方法时出错。

方法＆＃39; IOrderedEnumerable的类型参数 System.Linq.Enumerable.OrderBy（此 IEnumerable，Func，IComparer）＆＃39;不可能是从用法推断。尝试明确指定类型参数。

public static void Sort<T>(ref List<T> list, string propertyName, SortDirection direction)
{
    list = direction == SortDirection.Ascending
        ? list.OrderBy(x => x.GetType().GetProperty(propertyName).GetValue(x, null), new CustomComparer()).ToList()
        : list.OrderByDescending(x => x.GetType().GetProperty(propertyName).GetValue(x, null), new CustomComparer()).ToList();
}

我知道订单设置不正确有人有任何建议吗？

感谢。

public class CustomComparer : IComparer<object>
{
    public int Compare(object x, object y)
    {
    }
}

Answer 1

在<T, object>方法中明确指定类型参数OrderByDescending。

public class MyComparer : IComparer<object>
{
    public int Compare(object x, object y)
    {
        throw new NotImplementedException();
    }
}


    public static void Sort<T>(ref List<T> list, string propertyName)
    {
        list = list.OrderByDescending<T, object>(x => x.GetType().GetProperty(propertyName).GetValue(x, null), new MyComparer()).ToList();
    }

使用自定义编译器扩展自定义排序

1 个答案: