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LINQ列表包含(x= >…)-CS0103x不存在于当前上下文中(在前文内)

ExternalUse · 技术社区 · 6 年前

我有两个简单的列表要同步。 List<Guid> untrackedList List<Foo> trackedList 包含许多对象 Foo 具有Guid的ID属性的。此列表由实体框架跟踪,因此我要为未跟踪列表中的未跟踪列表中的未跟踪列表添加新项,并从未跟踪列表中移除未跟踪列表中的所有项。

public void MyTestMethod()
{
    const int someThing = 1000;
    var untrackedList = new List<Guid>()
    {
        new Guid("8fcfb512-ca00-4463-b98a-ac890b3ac4da"),
        new Guid("6532b60b-f047-4a96-9e5f-c5a242f9a1f5"),
        new Guid("103cb7e4-1674-490c-b299-4b20d90e706c"),
        new Guid("6c933cce-fb0e-4e1b-bbc3-e62235933cc8")
    };
    var trackedList = new List<Foo>()
    {
        new Foo() { SomeId = new Guid("6532b60b-f047-4a96-9e5f-c5a242f9a1f5"), Something = someThing },
        new Foo() { SomeId = new Guid("12345678-abcd-1234-1234-1234567890ab"), Something = someThing }
    };
    // testing Find and Exists
    var testFind = trackedList.Find(x => x.SomeId == new Guid("6532b60b-f047-4a96-9e5f-c5a242f9a1f5")); // finds one Foo
    var testExists = trackedList.Exists(x => x.SomeId == new Guid("12345678-abcd-1234-1234-1234567890ab")); // == true

    foreach (var guid in untrackedList)
    {
        // add all items not yet in tracked List
        if (!trackedList.Exists(x => x.SomeId == guid))
        {
            trackedList.Add(new Foo() { SomeId = guid, Something = someThing });
        }
    }
    // now remove all from trackedList that are not also in untracked List (should remove 12345678-...)
    trackedList.RemoveAll(x=> !untrackedList.Contains(x.SomeId)); // successful, but also shows CS0103 in the debugger
}