C＃WPF项目实体框架不会在DB中添加记录 [英] C# WPF project entity framework will not add record in DB

问题描述

大家好，我有一个C＃WPF项目，我使用ADO.net数据模型为其添加了Entity Framework。我有一个.mdf数据库，里面有一个表和数据。当我调用data.ToList（）方法时，我从数据库中获取正确的数据到我的数据网格中。这是正确的。我遇到的问题是当我创建/插入新文件到数据库时，记录不会被保存。我也得到0错误。我在网上阅读了几个小时试图解决这个问题，到目前为止，我想出的可能是因为我的连接字符串，因为我有|数据目录|或类似的东西可能呢？当我将所选用户发送到我创建的下一个屏幕时，我还可以将用户加载到屏幕中。只是无法弄清楚为什么我的用户不会保存到数据库。

Hello all I have a C# WPF project and I added Entity Framework to it with a ADO.net data model. I have a .mdf database with a table in it and data. When I call the data.ToList() method I get the correct data from my db into my datagrid. So that is correct. The issue I am having is when I go to create/insert a new file into the database the record does not get saved. I also get 0 errors. I been reading online for hours trying to figure this out and so far all I came up with is maybe its because of my connection string because I have |data directory| or something like that it is maybe? I can also load the user into the screen when I send the selected user to the next screen I have created. Just cannot figure out why my user will not save to the database.

//connstring –
<connectionStrings>
    <add name="EFcontext" connectionString="metadata=res://*/EFModel.csdl|res://*/EFModel.ssdl|res://*/EFModel.msl;provider=System.Data.SqlClient;provider connection string="data source=(LocalDB)\MSSQLLocalDB;attachdbfilename=|DataDirectory|\EntityFramewordDB.mdf;integrated security=True;MultipleActiveResultSets=True;App=EntityFramework"" providerName="System.Data.EntityClient" />
  </connectionStrings>
public class CRUD
    {
        //get the entity framework model context that was created.
        private EFcontext framework = null;

        public CRUD()
        {
            framework = new EFcontext();
        }

        public Person GetPersonById(int personId)
        {
            return framework.People.Find(personId);
        }

        public List<Person> GetAllPeopleByList()
        {
            return framework.People.ToList();
        }

        public void CreatePerson(Person person)
        {
            if(person != null)
            {
                framework.People.Add(person);
                framework.SaveChanges();
            }
        } public partial class MainWindow : Window
    {
        private CRUD entityFramework;
        private Person dataGridPerson;

        public MainWindow()
        {
            InitializeComponent();
            entityFramework = new CRUD();
            PopulateDataGrid();
        }

        private void PopulateDataGrid()
        {
            DataGridPeople.ItemsSource = entityFramework.GetAllPeopleByList();
        }

        private void BtnCreate_Click(object sender, RoutedEventArgs e)
        {
            Window CreatePerson = new CreateUpdateWindow();
            CreatePerson.Show();
            Close();
        } public partial class CreateUpdateWindow : Window
    {
        private CRUD entityFramework;
        private Person personWindowObject; 							public CreateUpdateWindow()
        {
            InitializeComponent();
            entityFramework = new CRUD();

        private void BtnSave_Click(object sender, RoutedEventArgs e)
        {
            Person personObject = new Person();
            Window mainWindow = new MainWindow();                    DateTime dateNow = DateTime.Now;
                    personObject.DateCreated = dateNow;
                    entityFramework.CreatePerson(personObject);
                    MessageBox.Show("Created new person.", "Created");
                    mainWindow.Show();
                    Close();
                }
            
}
//copied all sections of my code what is being used for creating user and to add 2 db

我尝试过：



在网上看了几个小时尝试不同的方式可能会出现问题不确定？

What I have tried:

looking online for hours trying different ways maybe connstring problem unsure?

推荐答案

你的 MainWindow 构造函数将网格绑定到数据库中的当前记录。



您的 BtnSave_Click 方法在将新记录添加到数据库之前创建一个新的 MainWindow 实例。



因此，您的主窗口无法显示新记录，因为它在数据加载时不存在。



尝试移动在 CreatePerson 调用之后创建新 MainWindow 实例的行：

Your MainWindow constructor binds the grid to the current records in the database.

Your BtnSave_Click method creates a new MainWindow instance before adding the new record to the database.

Therefore, your main window can't show the new record, because it doesn't exist at the point the data was loaded.

Try moving the line that creates the new MainWindow instance after the CreatePerson call:

private void BtnSave_Click(object sender, RoutedEventArgs e)
{
    Person personObject = new Person();
    DateTime dateNow = DateTime.Now;
    personObject.DateCreated = dateNow;
    // TODO: You probably want to set some other properties here...
    entityFramework.CreatePerson(personObject);
    MessageBox.Show("Created new person.", "Created");
    
    Window mainWindow = new MainWindow();                    
    mainWindow.Show();
    Close();
}

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