C# PredicateBuilder确实返回所有结果，并且可以'；我找不到罪犯

我正在尝试实现PredicateBuilder，并创建了一个简单的测试。 我目前正在使用PredicateBuilderDelegate，因为我正在测试一个

列表

问题是，当我运行测试时，我没有“过滤”记录和集合包含相同的元素，我不明白为什么会发生这种情况

FakeEntity类：

public class FakeEntity {
    public int Id { get; set; }
    public string Name { get; set; }
    public bool IsDeleted { get; set; }
    public static Func<FakeEntity, bool> NotDeleted() {
        var predicate = PredicateBuilderDelegate.True<FakeEntity>();
        predicate.And(e => !e.IsDeleted);
        return predicate;
    }
}

[TestClass]
public class PredicateBuilderTest {
    [TestMethod]
    public void Test() {
        var collection = new List<FakeEntity>() { new FakeEntity { IsDeleted = true }, new FakeEntity { IsDeleted = false } };
        var result = collection.Where(FakeEntity.NotDeleted()).ToList();
        CollectionAssert.AreNotEquivalent(collection, result); // FAIL!
        Assert.IsTrue(result.Count() == 1); // FAIL !!

    }
}

public static class PredicateBuilderDelegate {
    public static Func<T, bool> True<T>() { return f => true; }
    public static Func<T, bool> False<T>() { return f => false; }

    public static Func<T, bool> Or<T>(this Func<T, bool> expr1,
                                       Func<T, bool> expr2) {
        return t => expr1(t) || expr2(t);
    }

    public static Func<T, bool> And<T>(this Func<T, bool> expr1,
                                       Func<T, bool> expr2) {
        return t => expr1(t) && expr2(t);
    }
}

公共类FakeEntity{
公共int Id{get；set；}
公共字符串名称{get；set；}
公共布尔被删除{get；set；}
公共静态函数NotDeleted（）{
var predicate=PredicateBuilderDelegate.True（）；
谓词和（e=>！e.IsDeleted）；
返回谓词；
}
}

测试：

public class FakeEntity {
    public int Id { get; set; }
    public string Name { get; set; }
    public bool IsDeleted { get; set; }
    public static Func<FakeEntity, bool> NotDeleted() {
        var predicate = PredicateBuilderDelegate.True<FakeEntity>();
        predicate.And(e => !e.IsDeleted);
        return predicate;
    }
}

[TestClass]
public class PredicateBuilderTest {
    [TestMethod]
    public void Test() {
        var collection = new List<FakeEntity>() { new FakeEntity { IsDeleted = true }, new FakeEntity { IsDeleted = false } };
        var result = collection.Where(FakeEntity.NotDeleted()).ToList();
        CollectionAssert.AreNotEquivalent(collection, result); // FAIL!
        Assert.IsTrue(result.Count() == 1); // FAIL !!

    }
}

public static class PredicateBuilderDelegate {
    public static Func<T, bool> True<T>() { return f => true; }
    public static Func<T, bool> False<T>() { return f => false; }

    public static Func<T, bool> Or<T>(this Func<T, bool> expr1,
                                       Func<T, bool> expr2) {
        return t => expr1(t) || expr2(t);
    }

    public static Func<T, bool> And<T>(this Func<T, bool> expr1,
                                       Func<T, bool> expr2) {
        return t => expr1(t) && expr2(t);
    }
}

[TestClass]
公共类谓词BuilderTest{
[测试方法]
公开无效测试（）{
var collection=new List（）{new FakeEntity{IsDeleted=true}，new FakeEntity{IsDeleted=false}；
var result=collection.Where（FakeEntity.NotDeleted（））.ToList（）；
集合assert.AreNotEquivalent（集合，结果）；//失败！
Assert.IsTrue（result.Count（）==1）；//失败！！
}
}

PredicateBuilderDelegate:

public class FakeEntity {
    public int Id { get; set; }
    public string Name { get; set; }
    public bool IsDeleted { get; set; }
    public static Func<FakeEntity, bool> NotDeleted() {
        var predicate = PredicateBuilderDelegate.True<FakeEntity>();
        predicate.And(e => !e.IsDeleted);
        return predicate;
    }
}

[TestClass]
public class PredicateBuilderTest {
    [TestMethod]
    public void Test() {
        var collection = new List<FakeEntity>() { new FakeEntity { IsDeleted = true }, new FakeEntity { IsDeleted = false } };
        var result = collection.Where(FakeEntity.NotDeleted()).ToList();
        CollectionAssert.AreNotEquivalent(collection, result); // FAIL!
        Assert.IsTrue(result.Count() == 1); // FAIL !!

    }
}

public static class PredicateBuilderDelegate {
    public static Func<T, bool> True<T>() { return f => true; }
    public static Func<T, bool> False<T>() { return f => false; }

    public static Func<T, bool> Or<T>(this Func<T, bool> expr1,
                                       Func<T, bool> expr2) {
        return t => expr1(t) || expr2(t);
    }

    public static Func<T, bool> And<T>(this Func<T, bool> expr1,
                                       Func<T, bool> expr2) {
        return t => expr1(t) && expr2(t);
    }
}

公共静态类PredicateBuilderDelegate{
public static Func True（）{return f=>True；}
public static Func False（）{return f=>False；}
公共静态函数或（此函数expr1，
Func expr2）{
返回t=>expr1（t）| | expr2（t）；
}
公共静态函数和（此函数expr1，
Func expr2）{
返回t=>expr1（t）和&expr2（t）；
}
}

And方法返回一个新的谓词。它不会通过改变谓词来改变它。（委托毕竟是不可变的。）您忽略了方法的返回值。

！非常感谢。