对泛型 iCollection(Of T) 进行排序的扩展方法

Question

我正在尝试扩展一个通用集合，使其可以按我自己的标准进行排序。

这就是我使用 Linq 的方式：

Dim sortedList = ViewCollection.OrderByDescending(Function(x) x.ViewName.Replace(" ", "").Replace(".", "").Trim.All(AddressOf Char.IsLetter)).ThenByDescending(Function(x) x.ViewName.Replace(" ", "").Replace(".", "").Trim.Any(AddressOf Char.IsDigit)).ThenBy(Function(x) x.ViewName.Replace(" ", "").Replace(".", "").Trim).ToList()

所以，这是我正在处理的排序方法扩展：

<System.Runtime.CompilerServices.Extension()> _
        Public Function SortCollection(Of T)(ByVal Collection As ICollection(Of T), ByVal PropertyName As String) As ICollection(Of T)

            For Each p As System.Reflection.PropertyInfo In Collection.GetType().GetProperties()
                If p.Name = PropertyName Then
                    result = Collection.ToList() ' I need to replace this with the sorting criteria posted above
                End If
            Next

            Return result
        End Function

我似乎无法找到一种方法来传递我想要使用的通用对象的哪些属性作为字母排序标准。

有什么线索吗？

Answer 1

您需要获取PropertyDescriptor 并使用它对集合进行排序。

<Extension()> _
Public Function Sort(Of T)(ByVal collection As IEnumerable(Of T), ByVal propertyName As String, direction As ListSortDirection) As IEnumerable(Of T)
    Dim descriptor As PropertyDescriptor = TypeDescriptor.GetProperties(GetType(T)).Find(propertyName, True)
    If (direction = ListSortDirection.Descending) Then
        Return (From item As T In collection Select item Order By descriptor.GetValue(item) Descending)
    Else
        Return (From item As T In collection Select item Order By descriptor.GetValue(item) Ascending)
    End If
End Function

用法

MessageBox.Show(String.Join(Environment.NewLine, {"xxxxx", "xxx", "x", "xxxx", "xx"}.Sort("Length", ListSortDirection.Ascending)))

输出：

x
xx
xxx
xxxx
xxxxx