如何通过BindingNavigator将DataGridView的记录插入，更新和删除DataBase [英] How to insert, update and delete records of a DataGridView to DataBase via BindingNavigator

问题描述

我有一个学生表和我的数据库中的一些其他表，名为大学，我使用了实体框架在我的winforms应用程序中连接到它。

I have a Student table and a bunch of other tables in my database called University and I used Entity Framework to connect to it in my winforms application.

我从我的Entity Framework模型中的 Student 表创建了一个 DataSource 。

I created a DataSource from the Student table inside my Entity Framework model.

然后我将 DataSource 拖到我的表单上（见下面的图片）

我知道如何填充学生的记录表（这里只是我的DB中的一个记录）到 DataGridView 中，使用这段代码没有问题：

then I dragged the DataSource on to my form.(See the pic below)
I know how to populate the records of the student table (here is just one record in my DB) into the DataGridView, with no problem using this piece of code:

//An instance of my EFModel
    Oublic UniversityEntities UE = new UniversityEntities();
 private void Form1_Load_1(object sender, EventArgs e)
    {
        studentBindingSource.DataSource = UE.Students.ToList();
    }

但是我想使用 BindingNavigator 插入/更新/从数据库中删除记录，我不知道如何可能，考虑到我使用实体框架。

But I want to use BindingNavigator to insert/update/delete records from/to the database and I don't khow how it's possible, considering that I use Entity Framework.

例如，我尝试保存更改后编辑一行，但它没有工作：

For example,I tried this to save changes after editing a row, but it didn't work:

 private void studentBindingNavigatorSaveItem_Click(object sender, EventArgs e)
    {
        UE.SaveChanges();
    }

推荐答案

我知道这是一个老线程但是我遇到同样的问题，在这里没有回答。

I know it's an old thread but I faced the same problem with no answer here.

这一行打破了DataSource与上下文的连接：

this line is breaking DataSource's connection to context:

studentBindingSource.DataSource = UE.Students.ToList();

将其更改为：

studentBindingSource.DataSource = UE.Students;

但它会抛出异常，所以我只是绑定到本地数据：

but it throws an exception, so I just bind it to local data:

studentBindingSource.DataSource = UE.Students.Local;

此外，您需要确保本地数据在绑定前已填写。

Also you need to make sure local data has filled before binding.

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