[英]Having problem inserting child list of objects with included textblobs
我希望有人可以對這個問題有所了解。 作為擴展的新手,這可能是我做錯了。 我有一個名為原因的 object:
public class Reason
{
[PrimaryKey, AutoIncrement]
public int id { get; set; }
public string Description { get; set; }
[OneToMany]
public List<MiniGroup> Groups {get;set; }
}
然后 MiniGroup object 看起來像這樣:
public class MiniGroup
{
[AutoIncrement, PrimaryKey]
public int id { get; set; }
public string TeamNumber { get; set; }
[TextBlob("guidBlog")]
public List<string> StudentGuids { get; set; }
[TextBlob("nameBlob")]
public List<string> StudentNames { get; set; }
public string guidBlob { get; set; }
public string nameBlob { get; set; }
[ForeignKey(typeof(Reason))]
public int ReasonID { get; set; }
}
我毫不費力地創建了這兩個表。 問題是插入數據。 我試過了
public async Task AddNewReasonsAsync(List<Reason> reasons)
{
foreach (Reason reason in reasons)
{
try
{
await conn.InsertWithChildrenAsync(reason);
await conn.InsertAllWithChildrenAsync(reason.Groups, true);
StatusMessage = string.Format("Added [Name: {0})", reason.Groups.Count);
}
catch (Exception ex)
{
// now, try to update
try
{
await conn.UpdateWithChildrenAsync(reason.Groups);
await conn.UpdateWithChildrenAsync(reason);
}
catch (Exception)
{
StatusMessage = string.Format("Failed to add {0}. Error: {1}", reason.Groups.Count, ex.Message);
}
StatusMessage = string.Format("Failed to add {0}. Error: {1}", reason.Groups.Count, ex.Message);
}
}
}
此代碼導致 System.NullReferenceException: Object reference not set to an instance of object with the following stack trace. 我檢查了 object,唯一的 null 值是 blob 目標。 我的理解是在插入期間填充這些內容。
at SQLiteNetExtensions.Extensions.TextBlob.TextBlobOperations.UpdateTextBlobProperty (System.Object element, System.Reflection.PropertyInfo relationshipProperty) [0x00041] in C:\projects\sqlite-net-extensions\SQLiteNetExtensions\Extensions\TextBlob\TextBlobOperations.cs:54
at SQLiteNetExtensions.Extensions.WriteOperations.RefreshForeignKeys (System.Object element) [0x000b8] in C:\projects\sqlite-net-extensions\SQLiteNetExtensions\Extensions\WriteOperations.cs:368
at SQLiteNetExtensions.Extensions.WriteOperations.UpdateWithChildren (SQLite.SQLiteConnection conn, System.Object element) [0x00000] in C:\projects\sqlite-net-extensions\SQLiteNetExtensions\Extensions\WriteOperations.cs:39
at SQLiteNetExtensions.Extensions.WriteOperations.InsertAllWithChildrenRecursive (SQLite.SQLiteConnection conn, System.Collections.IEnumerable elements, System.Boolean replace, System.Boolean recursive, System.Collections.Generic.ISet`1[T] objectCache) [0x0006d] in C:\projects\sqlite-net-extensions\SQLiteNetExtensions\Extensions\WriteOperations.cs:169
at SQLiteNetExtensions.Extensions.WriteOperations.InsertAllWithChildren (SQLite.SQLiteConnection conn, System.Collections.IEnumerable elements, System.Boolean recursive) [0x00000] in C:\projects\sqlite-net-extensions\SQLiteNetExtensions\Extensions\WriteOperations.cs:91
at SQLiteNetExtensionsAsync.Extensions.WriteOperations+<>c__DisplayClass3_0.<InsertAllWithChildrenAsync>b__0 () [0x00013] in C:\projects\sqlite-net-extensions\SQLiteNetExtensionsAsync\Extensions\WriteOperations.cs:103
at System.Threading.Tasks.Task.InnerInvoke () [0x0000f] in /Users/builder/jenkins/workspace/archive-mono/2019-10/android/release/external/corert/src/System.Private.CoreLib/src/System/Threading/Tasks/Task.cs:2476
at System.Threading.Tasks.Task.Execute () [0x00000] in /Users/builder/jenkins/workspace/archive-mono/2019-10/android/release/external/corert/src/System.Private.CoreLib/src/System/Threading/Tasks/Task.cs:2319
--- End of stack trace from previous location where exception was thrown ---
at StudentGroupsMobile.Data.ReasonDBManager.AddNewReasonsAsync (System.Collections.Generic.List`1[T] reasons) [0x00216] in C:\Users\toman\source\repos\StudentGroupsMobile_XF\StudentGroupsMobile\Data\ReasonDBManager.cs:37
我什至嘗試遍歷 MiniGroup 列表並單獨插入每個列表,這會導致相同的錯誤。
有人看到我做錯了嗎? 任何幫助是極大的贊賞!
所以我通過簡化設置解決了這個問題。 我沒有將原因與組建立 OneToMany 關系,而是將組變成了一個 TextBlob。 以下是工作對象:
public class Reason
{
[PrimaryKey, AutoIncrement]
public int id { get; set; }
public string Description { get; set; }
[TextBlob("GroupsBlob")]
public List<MiniGroup> Groups {get;set; }
public string GroupsBlob { get; set; }
}
public class MiniGroup
{
[AutoIncrement, PrimaryKey]
public int id { get; set; }
public string TeamNumber { get; set; }
[TextBlob("guidBlog")]
public List<string> StudentGuids { get; set; } //= new List<string>();
[TextBlob("nameBlob")]
public List<string> StudentNames { get; set; } //= new List<string>();
public string guidBlob { get; set; }
public string nameBlob { get; set; }
//[ForeignKey(typeof(Reason))]
//public int ReasonID { get; set; }
}
那么處理就變得簡單多了:
public async Task AddNewReasonsAsync(List<Reason> reasons)
{
try
{
await conn.InsertAllWithChildrenAsync(reasons);
}
catch (Exception)
{
await conn.UpdateWithChildrenAsync(reasons);
}
}
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