我认为DynamicData中的Sort不能正常工作。可能是我不知道如何使用?示例:
using DynamicData;
using DynamicData.Binding;
using ReactiveUI;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Reactive;
using System.Reactive.Linq;
namespace DynamicDataTest
{
public class Element:ReactiveObject
{
string name;
public string Name { get => name; set => this.RaiseAndSetIfChanged(ref name,value); }
int val;
public int Value { get => val; set => this.RaiseAndSetIfChanged(ref val, value); }
}
public class CollectionTest:ReactiveObject
{
public SourceCache<Element, int> source = new SourceCache<Element, int>(e => e.Value);
public ReadOnlyObservableCollection<string> Info;
public void Print()
{
Console.WriteLine("Begin print");
foreach (var obj in Info) Console.WriteLine(obj);
Console.WriteLine("End print");
}
public CollectionTest()
{
source.AddOrUpdate(new Element() { Name = "Hello1", Value = 4 });
source.AddOrUpdate(new Element() { Name = "Hello2", Value = 3 });
var connection = source.Connect().Sort(SortExpressionComparer<Element>.Ascending(e => e.Value));
connection.Transform(t=>t.Name).Bind(out Info).Subscribe();
}
}
class Program
{
static void Main(string[] args)
{
var test = new CollectionTest();
test.Print();
test.source.AddOrUpdate(new Element() { Name = "Hello1", Value = 4 });
test.source.AddOrUpdate(new Element() { Name = "Hello2", Value = 3 });
test.Print();
}
}
}
结果很奇怪:第一个打印显示顺序Hello2 Hello1,第二个显示-Hello1 Hello2。怎么了?
使用源缓存时,排序仅受bind,page和virtualise运算符尊重。由于性能原因,因为状态存储在没有排序概念的字典中。因此,您应该在绑定之前立即应用排序。
另一方面,对于源列表,状态存储在一个列表中,该列表可以理解由于被索引而导致的顺序。在这种情况下,可以在链的任何地方应用排序。