SQlitedatabase无法更新和删除行

Question

我正在使用Xamarin表单，我使用Sqlite-net-pcl nuget包实现了SQLite数据库。问题是数据库最初保存了一行但无法更新或删除任何行。这是我使用Key保存和删除数据库行的代码。

    public Task<int> SaveItemAsync(SQLiteRowData item)
    {
        if (item.ID != 0)
        {
            return database.UpdateAsync(item);
        }
        else
        {
            return database.InsertAsync(item);
        }
    }
     public Task<int> DeleteItemAsync(SQLiteRowData item)
    {
        return database.DeleteAsync(item);
    }

    public Task<int> DeleteItemAsyncWithKey(string key)
    {
        Task<SQLite.SQLiteRowData> lSQLiteRowTaskData = 
        App.sqliteConnectionPath.GetItemForKeyAsync(key);
        SQLite.SQLiteRowData lSQLiteRowData  = lSQLiteRowTaskData.Result;
        return database.DeleteAsync(lSQLiteRowData);
    }

    public async Task<bool> DeleteUserPreferencesAsync()
    {
        Boolean lReturnValue = false;

        try
        {
            Task<SQLiteRowData> lSQLiteRowDataTask = App.sqliteConnectionPath.GetItemForKeyAsync("UserPreferences");                SQLiteRowData lSQLiteRowData = lSQLiteRowDataTask.Result;
            if (lSQLiteRowData != null) {
                await DeleteItemAsync(lSQLiteRowData);
                lReturnValue = true;
            }
        }
        catch (Exception ex)
        {
            EMAUtilities.printLogs(ex.Message);
        }
        return lReturnValue;
    }

   // Used for saving userpreference
   SQLiteRowData lSQLiteRowData = new SQLiteRowData("UserPreferences", lValue);
   Task<int> x = SaveItemAsync(lSQLiteRowData);

任何人都可以指出我在此做过的错误，提前谢谢