为什么我的 SubmitChanges() 在 LINQ-to-SQL 中不起作用? [英] Why isn't my SubmitChanges() working in LINQ-to-SQL?

问题描述

我在 WPF 应用程序中创建了一个 .MDF 数据库.

I created a .MDF database in my WPF application.

然后我生成了 LINQ-to-SQL 类并使用 LINQ 获取所有客户.

I then generated LINQ-to-SQL classes and used LINQ get all the customers.

然后我浏览了他们并更改了他们的每个姓氏.

Then I run through them and change each of their last names.

但是，当我调用 SubmitChanges 时，数据库保持不变.

However, when I call SubmitChanges, the database remains unchanged.

我认为这是 SubmitChanges() 的目的，提交对数据库的更改?

I thought that was the purpose of SubmitChanges(), to submit changes to the database?

我遗漏了什么，如何提交更改"回我的数据库?

What am I missing, how do I "submit changes" back to my database?

public Window1()
{
    InitializeComponent();

    Main2DataContext _db = new Main2DataContext();
    var customers = from c in _db.Customers
                    select c;

    foreach (var customer in customers)
    {
        customer.LastName = "CHANGED lastname"; //ListBox shows changes 
    }

    _db.SubmitChanges(); //does NOT save to database (???)

}

推荐答案

我想我知道问题出在哪里了.您使用的是本地 .mdf 文件吗?如果是这种情况，请检查您的 bin/debug 文件夹.我敢打赌，您在那里有一个包含更改的数据库.我认为您的项目中有一个 .mdf 文件，每次构建时都会将其复制到 bin/debug 文件夹中.因此，更改将保存到副本中，而您没有看到它反映在直接驻留在项目中的副本中.

I think I know what the problem is. Are you using a local .mdf file? If that's the case, check your bin/debug folder. I bet you have a database in there with the changes. I think you have an .mdf file in your project that is getting copied to the bin/debug folder everytime you build. Therefore the changes are getting saved to the copy, and you're not seeing it reflected in the copy that resides directly in your project.

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