数据库中的数据未更新，使用 C#、WPF、Entity framework 和 Visual studio 2012

Question

这个问题参考了我这里的旧问题：Primary key in datagrid is always zero

在我之前的问题中，我正在处理具有许多关系的非常大的数据库，所以我想尝试并测试这个基本的（非常基本的）项目。

我所做的是创建简单的基本 wpf 应用程序。添加了只有一个 table 的本地数据库，其中有两个 columns.One 是 id 列，它是主键和自动 incremented.The 其他很简单 varchar.I 添加了它作为数据源并从中创建了网格该数据源。

这是我的 xaml:

<Window
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:local="clr-namespace:WpfApplication4" mc:Ignorable="d" x:Class="WpfApplication4.MainWindow"
    Title="MainWindow" Height="350" Width="525" Loaded="Window_Loaded_1">
<Window.Resources>
    <CollectionViewSource x:Key="tablesViewSource" d:DesignSource="{d:DesignInstance {x:Type local:Table}, CreateList=True}"/>
</Window.Resources>
<Grid DataContext="{StaticResource tablesViewSource}">
    <DataGrid x:Name="tablesDataGrid" AutoGenerateColumns="False" EnableRowVirtualization="True" ItemsSource="{Binding}" Margin="47,24,70,95" RowDetailsVisibilityMode="VisibleWhenSelected">
        <DataGrid.Columns>
            <DataGridTextColumn x:Name="idColumn" Binding="{Binding Id}" Header="Id" Width="SizeToHeader"/>
            <DataGridTextColumn x:Name="nameColumn" Binding="{Binding name}" Header="name" Width="SizeToHeader"/>
        </DataGrid.Columns>
    </DataGrid>
    <Button Content="Button" HorizontalAlignment="Left" Margin="221,266,0,0" VerticalAlignment="Top" Width="75" Click="Button_Click_1"/>

</Grid>

仅有的两行代码是我写的。休息是自动的 generated.Now 我想从 gridview 更新我的数据，但最大的问题是数据不是 updated.It 继续添加零。

我在这里添加了整个 cs 文件。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace WpfApplication4
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
    }

    private System.Data.Objects.ObjectQuery<Table> GetTablesQuery(Database1Entities database1Entities)
    {
        System.Data.Objects.ObjectQuery<WpfApplication4.Table> tablesQuery = database1Entities.Tables;
        // Returns an ObjectQuery.
        return tablesQuery;
    }

    private void Window_Loaded_1(object sender, RoutedEventArgs e)
    {

        WpfApplication4.Database1Entities database1Entities = new WpfApplication4.Database1Entities();
        // Load data into Tables. You can modify this code as needed.
        System.Windows.Data.CollectionViewSource tablesViewSource = ((System.Windows.Data.CollectionViewSource)(this.FindResource("tablesViewSource")));
        System.Data.Objects.ObjectQuery<WpfApplication4.Table> tablesQuery = this.GetTablesQuery(database1Entities);
        tablesViewSource.Source = tablesQuery.Execute(System.Data.Objects.MergeOption.AppendOnly);
    }

    private void Button_Click_1(object sender, RoutedEventArgs e)

    {
        var context = new WpfApplication4.Database1Entities();
       // Database1Entities db = new Database1Entities();
        // db.SaveChanges();
        context.SaveChanges();
    }
}

} `

我开始怀疑自己的基础了。请帮助。

Answer 1

试试这个：

private void Button_Click_1(object sender, RoutedEventArgs e)
    {
        var context = new WpfApplication4.Database1Entities();
        var table = context.Set<YourTable>();
        table.Add(new YourTable { Id = id, Name = "John Doe" });
        context.SaveChanges();
    }

Answer 2

这对我有用（调整变量名称）：

 using System.Data.Entity;

    private Database1Entities  _context = new Database1Entities (); 

    private void Window_Loaded(object sender, RoutedEventArgs e) {

        System.Windows.Data.CollectionViewSource tableViewSource = ((System.Windows.Data.CollectionViewSource)(this.FindResource("tableViewSource")));
        _context.Table.Load();
        tableViewSource.Source = _context.Table.Local;
    }

    private void Button_Click(object sender, RoutedEventArgs e) {
        _context.SaveChanges();
        tableDataGrid.Items.Refresh(); 
    }

更多信息位于：https://msdn.microsoft.com/en-us/data/jj574514.aspx

数据库中的数据未更新，使用 C#、WPF、Entity framework 和 Visual studio 2012

Data is not updated in database, using C#,WPF, Entity framework and Visual studio 2012

c#

wpf

datagrid

entity-framework

visual-studio-2012