Xamarin Firebase DeleteAsync

Question

我在 Xamarin Android 应用上从 Firebase 数据库中删除项目时遇到问题。

我收到 400（错误请求）错误

删除方法：

private async void RemovePost(string ActivityID)
{
    var firebase = new FirebaseClient(FirebaseURL);
    await firebase.Child("posts").Child(ActivityID).DeleteAsync();

    var intent = new Intent(mContext, typeof(MyProfileActivity));
    mContext.StartActivity(intent);
}

型号：

public class Post
{
    public string ActivityID { get; set; }

    public string OwnerID { get; set; }

    public string ActivityTitle { get; set; }

    public string ActivitySport { get; set; }

    public DateTime ActivityDate { get; set; }

    public DateTime ActivityTime { get; set; }

    public string ActivityTown { get; set; }

    public string ActivityAddress { get; set; }

    public string ActivityPhone { get; set; }

    public string ActivityEmail { get; set; }

    public string ActivityDetails { get; set; }
}

Firebase 数据库表：

注意我传递给RemovePost方法的活动ID是“0”

Answer 1

那么，当您首先将记录保存到数据库时，为什么不将ActivityId 作为键呢？

var post = new Post {
    ActivityId = 0,
    //...other properties populated
}

var record = await firebase
    .Child("posts")
    .Child(post.ActivityId)
    .PostAsync(post));

var posts = await firebase
    .Child("posts")
    .OnceAsync<Post>();

foreach (var item in posts) {
    Console.WriteLine($"{item.Key} post has id {item.Object.ActivityId}");
}

await firebase.Child("posts").Child(post.ActivityID).DeleteAsync();

这样在查询记录时可以查询已知键

Answer 2

这个：

await firebase.Child("posts").Child(ActivityID)

将尝试将 ActivityID 与节点的根匹配，在您的情况下是值 KiG7ju8CsDfGW3eSBIn

尝试将您的 firebase 删除调用更改为以下内容：

await firebase.Child("posts").OrderBy("ActivityID").EqualTo(ActivityID).DeleteAsync();

更新

试试这个，这样你就可以调试了。设置一个断点并运行调用以查看结果。

//Get the record(s). Can be more than one if ActivityID value is repeated.
var posts = await firebase
    .Child("posts")
    .OrderBy("ActivityID")
    .EqualTo("0")
    .OnceAsync<Post>();

// Select only the first one
var firstPost = posts.FirstOrDefault();

// send to delete this
await firebase
    .Child("posts")
    .Child(firstPost?.Key)
    .DeleteAsync();