Question

我无法从本地数据库更新数据。这是我的代码：

private void appBarOkButton_Click(object sender, EventArgs e)
    {


        string selectedRowOrderId = "";
        if (NavigationContext.QueryString.TryGetValue("selectedItem", out selectedRowOrderId))
        {
            int selectedID = int.Parse(selectedRowOrderId);
            var query = from TblCustomers customer in orderDB.Customers
                        where customer.Id == selectedID
                        select customer;

           TblCustomers editCustomer = query.FirstOrDefault();
            if (editCustomer != null)
                editCustomer.Name = txtBoxCustomerName.Text;

                App.ViewModel.SaveChangesToDB();



                 // Return to the main page.
                if (NavigationService.CanGoBack)
                {
                    NavigationService.GoBack();
                }
            }
    }

这是模范方面：

public void SaveChangesToDB()
    {
        orderDB.SubmitChanges();
    }

当我尝试在数据库中更改某些内容时，Everythings在调试时看起来很正常。但最后没有任何改变。你能帮我吗？

Answer 1

编辑页面

XAML：

<phone:PhoneApplicationPage.Resources>
    <DataTemplate x:Key="ToDoListBoxItemTemplate">
            <TextBox HorizontalAlignment="Stretch" Text="{Binding ItemName,Mode=TwoWay}" FontSize="{StaticResource PhoneFontSizeLarge}" 
                Grid.Column="1" Grid.ColumnSpan="2" 
                VerticalAlignment="Top" Margin="-36, 12, 0, 0"
                     ></TextBox>
    </DataTemplate>
</phone:PhoneApplicationPage.Resources>

<Grid x:Name="LayoutRoot" Background="Transparent">
    <ListBox  
        x:Name="allToDoItemsListBox" 
        ItemsSource="{Binding AllToDoItems}" 
        Margin="12, 0, 12, 0" Width="440" 
        ItemTemplate="{StaticResource ToDoListBoxItemTemplate}" />
</Grid>

<phone:PhoneApplicationPage.ApplicationBar>
    <shell:ApplicationBar IsVisible="True" IsMenuEnabled="True">
        <shell:ApplicationBarIconButton 
            IconUri="/Images/appbar.check.rest.png" 
            Text="Save" 
            x:Name="newTaskAppBarButton" 
            Click="newTaskAppBarButton_Click"/>
    </shell:ApplicationBar>
</phone:PhoneApplicationPage.ApplicationBar>

代码背后：

public partial class EditPage : PhoneApplicationPage
{
    public EditPage()
    {
        InitializeComponent();
        DataContext = App.ViewModel;
    }

    protected override void OnNavigatedFrom(System.Windows.Navigation.NavigationEventArgs e)
    {
        App.ViewModel.SaveChangesToDB();
    }

    private void newTaskAppBarButton_Click(object sender, EventArgs e)
    {
        NavigationService.GoBack();
    }
}

为我工作

本地数据库更新现有记录 - Windows Phone 8

1 个答案: