扩展基本的移动天蓝色样本(.net后端)

问题描述

因此，我创建了一个Azure移动服务，下载了一个项目并运行它.首次启动后，我在数据库中看到一些新表:TodoItems(有2个项目)和_MigrationHistory.到目前为止一切顺利.

So, i create a azure mobile service, downloaded a project and run it.After the first launch, i see some new tables in DB: TodoItems (with 2 items) and _MigrationHistory. So far so good.

现在，我想添加一个额外的表.

Now, i'd like to add an extra table.

1. 我正在制作新模型MyModel:EntityData { public string MyData { get; set; }
2. 制作一个新的控制器MyModelController:TableController<MyModel>，它是TodoItemController的副本，其中TodoItem被替换为MyModel
3. 将public DbSet<MyModel> MyModels { get; set; }添加到MyProjectContext.cs
4. 在WebApiConfig中添加一行context.Set<MyModel>().Add(new MyModel{MyData= "test"});

1. I'm making new model MyModel:EntityData { public string MyData { get; set; }
2. Making a new controller MyModelController:TableController<MyModel> which is a copy of TodoItemController, where TodoItem is replaced with MyModel
3. Added public DbSet<MyModel> MyModels { get; set; } to MyProjectContext.cs
4. Adding to the WebApiConfig a line context.Set<MyModel>().Add(new MyModel{MyData= "test"});

我忘记了什么吗?

删除所有表并重新发布并运行我的移动应用程序后，我遇到 MobileServiceInvalidOperationException 异常，并且我的表为空(甚至TodoItems为空).

After deleting all tables and re-publishing and running my mobile application, i'm getting MobileServiceInvalidOperationException exception and my tables are empty (even TodoItems is empty).

编辑:我不确定问题的根源在哪里.如果要向移动应用添加一行

EDIT: i'm not sure where is the core of the problem. If to add to the mobile app a line

private IMobileServiceTable<MyModel> myItemsTable = App.MobileService.GetTable<MyModel>();

它将引发InvalidOperationException.但是MyModels表存在于数据库中，我可以通过数据库管理器看到它...

It would throw InvalidOperationException. But MyModels table exists in a db, i can see it via db manager...

EDIT2 :

• 好的，我删除了所有其他代码(使用MyModels)并删除了db中的所有表.重新发布移动服务，运行应用程序，然后再次看到2个表:TodoItems(有2个项目)和_MigrationHistory.
• 现在，我在MyProjectContext.cs中添加了行public DbSet<MyModel> MyModels { get; set; }，删除了db中的所有表，运行了app，现在我看到了3个表:MyModels，TodoItems(有2个项目)和_MigrationHistory.
• 当我添加行context.Set<MyModel>().Add(new MyModel{MyData= "test"});时-此后播种出错:我看到3个表MyModels，TodoItems和_MigrationHistory，但是TodoItems现在为空.

• Okay, i removed all additional code (with MyModels) and removed all tables in db. Re-publish mobile service, run app and again i see 2 tables: TodoItems (with 2 items) and _MigrationHistory.
• Now, i added line public DbSet<MyModel> MyModels { get; set; } to MyProjectContext.cs, removed all tables in db, run app and now i see 3 tables: MyModels, TodoItems (with 2 items) and _MigrationHistory.
• When i added line context.Set<MyModel>().Add(new MyModel{MyData= "test"}); - after this moment seeding went wrong: i see 3 tables MyModels, TodoItems and _MigrationHistory, but TodoItems is empty now.

推荐答案

问题出在context.Set<MyModel>().Add(new MyModel{MyData= "test"});行中.我忘了初始化Id:认为它会自动递增.

The problem was in line context.Set<MyModel>().Add(new MyModel{MyData= "test"});. I forgot to initialize Id: thought it would be autoincremented.

固定行是context.Set<MyModel>().Add(new MyModel{MyData= "test", Id = "666"});

这是我面临的另一个问题:如果应用程序的var myTable = MobileService.GetTable<MyModel>();行中有例外，请确保已将Id字段添加到模型中.

just another problem i faced: if there's exception in app's line var myTable = MobileService.GetTable<MyModel>();, be sure you added Id field to your model.

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