与众不同 windows phone (7) Local Database（本地数据库）

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与众不同 windows phone (7) - Local Database（本地数据库）

作者：webabcd


介绍
与众不同 windows phone 7.5 (sdk 7.1) 之本地数据库

• 概述
• 演示如何使用“本地数据库”

示例
1、概述
Summary.xaml

<phone:PhoneApplicationPage 
    x:Class="Demo.LocalDatabase.Summary"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
    xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    FontFamily="{StaticResource PhoneFontFamilyNormal}"
    FontSize="{StaticResource PhoneFontSizeNormal}"
    Foreground="{StaticResource PhoneForegroundBrush}"
    SupportedOrientations="Portrait" Orientation="Portrait"
    mc:Ignorable="d" d:DesignHeight="768" d:DesignWidth="480"
    shell:SystemTray.IsVisible="True">

    <Grid x:Name="LayoutRoot" Background="Transparent">
        <TextBlock TextWrapping="Wrap">
            <Run>本地数据库概述</Run>
            <LineBreak />
            <LineBreak />
            <Run>1、App 创建数据库时，其文件会被保存到独立存储；程序包内数据库只能被读取，如果需要更新它，则必须把其复制到独立存储后再操作</Run>
            <LineBreak />
            <Run>2、数据库结构发生改变时优先使用 DatabaseSchemaUpdater 来更新数据库结构；数据迁移是下策</Run>
            <LineBreak />
            <Run>3、只读场景下建议将 DataContext 的 ObjectTrackingEnabled 设置为 false（因为只读时不需要对象跟踪），从而关闭对象跟踪以减小内存使用量</Run>
            <LineBreak />
            <Run>4、在多线程操作本地数据库的场景下，建议使用互斥锁，即 System.Threading.Mutex</Run>
        </TextBlock>
    </Grid>
    
</phone:PhoneApplicationPage>

2、使用“本地数据库”的 Demo
Model层 - ModelBase.cs

using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

using System.ComponentModel;
using System.Data.Linq.Mapping;
using System.Data.Linq;

namespace Demo.LocalDatabase.Model
{
    public class ModelBase : INotifyPropertyChanged, INotifyPropertyChanging
    {
        // 实现 INotifyPropertyChanged 是为了属性变更后的通知
        public event PropertyChangedEventHandler PropertyChanged;
        protected void NotifyPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }


        // 实现 INotifyPropertyChanging 是为了最大限度地减少内存使用量（NotifyPropertyChanging 的用法：在属性赋值之前调用，具体可见 Category 或 Product）
        /*
         * 为什么会减少内存使用量呢？
         * 因为 LINQ to SQL 更改跟踪是通过维护每个对象的两个副本进行工作的，第一个副本保存原始数据，第二个副本有程序更改，这样提交更新时 LINQ to SQL 就知道哪些数据被更改了，从而只提交这些被更改的数据
         * INotifyPropertyChanging 接口允许应用程序在将修改后的数据提交到数据库前通知 DataContext，DataContext 可以将该通知用作创建副本的触发器，这样就不用保留第二个副本了，从而减少内存使用
         */
        public event PropertyChangingEventHandler PropertyChanging;
        protected void NotifyPropertyChanging(string propertyName)
        {
            if (PropertyChanging != null)
            {
                PropertyChanging(this, new PropertyChangingEventArgs(propertyName));
            }
        }
    }
}

Model层 - Category.cs

using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

using System.Data.Linq.Mapping;
using System.Data.Linq;

namespace Demo.LocalDatabase.Model
{
    /*
     * Table - 将类标记为数据库中的一个表
     * Index - 把类中的指定字段标记为索引字段
     */
    [Table]
    public class Category : ModelBase
    {
        // 版本列，可以显著改进表的更新性能
        [Column(IsVersion = true)]
        private Binary _version;


        private int _categoryId;
        /*
         * Column - 将属性标记为数据表中的一个字段
         *     IsPrimaryKey - 是否是主键
         *     IsDbGenerated - 数据是否由数据库自动生成，如自增列
         *     DbType = "INT NOT NULL Identity" - int类型，不能为null，标识列
         *     CanBeNull - 是否可以为 null
         *     AutoSync = AutoSync.OnInsert - 标记此值的作用是：当数据添加完成后，此属性的值会自动同步为数据库自增后的值
         */
        [Column(DbType = "INT NOT NULL IDENTITY", IsDbGenerated = true, IsPrimaryKey = true)]
        public int CategoryId
        {
            get { return _categoryId; }
            set
            {
                NotifyPropertyChanging("CategoryId");
                _categoryId = value;
                NotifyPropertyChanged("CategoryId");
            }
        }

        private string _name;
        [Column]
        public string Name
        {
            get { return _name; }
            set
            {
                NotifyPropertyChanging("Name");
                _name = value;
                NotifyPropertyChanged("Name");
            }
        }


        private EntitySet<Product> _products;
        /*
         * Association - 用于标记表之间的关联关系
         *     Storage - 指定用于保存关联数据的私有字段。本例中类型为 EntitySet<T> 的私有字段 _products 用于保存关联数据，本例中所谓的关联数据就是 Category 下的 Products
         *     ThisKey - 关联数据在本表中所对应的 key 字段
         *     OtherKey - 关联数据在他表中所对应的 key 字段
         *     IsForeignKey - 是否是外键
         */
        [Association(Storage = "_products", ThisKey = "CategoryId", OtherKey = "_categoryId")]
        public EntitySet<Product> Products
        {
            get { return this._products; }
            set 
            {
                /*
                 * Assign() - 将一个 EntitySet<T> 赋值给另一个 EntitySet<T> 
                 */
                // 将 value 赋值给 _products
                this._products.Assign(value); 
            }
        }


        // 指定 _products 做添加和删除操作时的关联操作
        public Category()
        {
            _products = new EntitySet<Product>
            (
                new Action<Product>(this.attach),
                new Action<Product>(this.detach)
            );
        }

        // _products 添加 Product 时的关联操作
        private void attach(Product product)
        {
            NotifyPropertyChanging("Product");
            product.Category = this;
        }

        // _products 删除 Product 时的关联操作
        private void detach(Product product)
        {
            NotifyPropertyChanging("Product");
            product.Category = null;
        }

    }
}

Model层 - Product.cs

using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

using System.Data.Linq.Mapping;
using System.Data.Linq;
using Microsoft.Phone.Data.Linq.Mapping;

namespace Demo.LocalDatabase.Model
{
    /*
     * Table - 将类标记为数据库中的一个表
     * Index - 把类中的指定字段标记为索引字段
     */
    [Table]
    [Index(Columns = "Name ASC, ProductId DESC", Name="MyIndex")]
    public class Product : ModelBase
    {
        // 版本列，可以显著改进表的更新性能
        [Column(IsVersion = true)]
        private Binary _version;


        private int _productId;
        /*
         * Column - 将属性标记为数据表中的一个字段
         *     IsPrimaryKey - 是否是主键
         *     IsDbGenerated - 数据是否由数据库自动生成，如自增列
         *     DbType = "INT NOT NULL Identity" - int类型，不能为null，标识列
         *     CanBeNull - 是否可以为 null
         *     AutoSync = AutoSync.OnInsert - 标记此值的作用是：当数据添加完成后，此属性的值会自动同步为数据库自增后的值
         */
        [Column(IsPrimaryKey = true, IsDbGenerated = true, DbType = "INT NOT NULL Identity", CanBeNull = false, AutoSync = AutoSync.OnInsert)]
        public int ProductId
        {
            get { return _productId; }
            set
            {
                if (_productId != value)
                {
                    NotifyPropertyChanging("ProductId");
                    _productId = value;
                    NotifyPropertyChanged("ProductId");
                }
            }
        }

        private string _name;
        [Column]
        public string Name
        {
            get { return _name; }
            set
            {
                if (_name != value)
                {
                    NotifyPropertyChanging("Name");
                    _name = value;
                    NotifyPropertyChanged("Name");
                }
            }
        }

        private double _price;
        [Column]
        public double Price
        {
            get { return _price; }
            set
            {
                if (_price != value)
                {
                    NotifyPropertyChanging("Price");
                    _price = value;
                    NotifyPropertyChanged("Price");
                }
            }
        }


        [Column]
        internal int _categoryId;

        private EntityRef<Category> _category;
        /*
         * Association - 用于标记表之间的关联关系
         *     Storage - 指定用于保存关联数据的私有字段。本例中类型为 EntityRef<T> 的私有字段 _category 用于保存关联数据，本例中所谓的关联数据就是 Product 所属的 Category
         *     ThisKey - 关联数据在本表中所对应的 key 字段
         *     OtherKey - 关联数据在他表中所对应的 key 字段
         *     IsForeignKey - 是否是外键
         */
        [Association(Storage = "_category", ThisKey = "_categoryId", OtherKey = "CategoryId", IsForeignKey = true)]
        public Category Category
        {
            get { return _category.Entity; }
            set
            {
                NotifyPropertyChanging("Category");

                // 更新 Storage 以及 ThisKey
                _category.Entity = value;
                if (value != null)
                    _categoryId = value.CategoryId;

                NotifyPropertyChanging("Category");
            }
        }
    }
}

Model层 - MyContext.cs

using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

using System.Data.Linq;

namespace Demo.LocalDatabase.Model
{
    public class MyContext : DataContext
    {
        public MyContext(string connectionString)
            : base(connectionString)
        { }

        public Table<Product> Products;

        public Table<Category> Categories;
    }
}

ViewModel层 - MyViewModel.cs

/*
 * 连接字符串设置
 *     1、data source - 本地数据库文件地址
 *          示例：data source=isostore:/database.sdf；appdata:/ 代表程序包内，isostore:/ 代表独立存储，默认为独立存储
 *     2、pwd - 密码
 *     3、max buffer size - 最大内存使用量（保存到磁盘之前会使用内存），默认值为 384，最大值为 5120，单位为 KB
 *     4、max database size - 数据库文件的最大大小，默认值为 32，最大值为 512，单位为 MB
 *     5、file mode - 操作数据库文件时的模式
 *          Read Write - 可读写，默认值
 *          Read Only - 只读
 *          Exclusive - 不允许其他进程打开或修改数据库
 *          Shared Read - 数据库打开后，允许其他进程读取，但不允许其他进程修改
 *     6、Culture Identifier - 区域代码，如中国大陆地区是 zh-CN（创建数据库时此属性才有用）
 *     7、Case Sensitive - 排序时是否区分大小写，默认值为 false（创建数据库时此属性才有用）
 */

using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

using System.ComponentModel;
using Demo.LocalDatabase.Model;
using Microsoft.Phone.Data.Linq;
using System.Collections.ObjectModel;

using System.Linq;
using System.Data.Linq;

namespace Demo.LocalDatabase.ViewModel
{
    public class MyViewModel : INotifyPropertyChanged
    {
        private MyContext _context;

        public MyViewModel()
        {
            DataLoadOptions dlo = new DataLoadOptions();
            dlo.LoadWith<Category>(p => p.Products);
            dlo.AssociateWith<Category>(p => p.Products.OrderByDescending(x => x.Price));

            _context = new MyContext("Data Source=isostore:/database.sdf");
            _context.LoadOptions = dlo;

            Init();

            Categories = new ObservableCollection<Category>(_context.Categories.ToList());
        }

        public void AddProduct(Product product)
        {
            var category = Categories.Single(p => p.CategoryId == product.Category.CategoryId);
            category.Products.Add(product);

            _context.Products.InsertOnSubmit(product);
            _context.SubmitChanges();
        }

        public void DeleteProduct(Product product)
        {
            var category = Categories.Single(p => p.CategoryId == product.Category.CategoryId);
            category.Products.Remove(product);

            _context.Products.DeleteOnSubmit(product);
            _context.SubmitChanges();
        }

        public void Init()
        {
            if (!_context.DatabaseExists())
            {
                _context.CreateDatabase();

                DatabaseSchemaUpdater dbUpdater = _context.CreateDatabaseSchemaUpdater();
                dbUpdater.DatabaseSchemaVersion = 0;
                dbUpdater.Execute();

                Category c1 = new Category { Name = "肉" };
                c1.Products.Add(new Product { Name = "牛肉", Price = 35.5 });
                c1.Products.Add(new Product { Name = "羊肉", Price = 38 });
                Category c2 = new Category { Name = "水果" };
                c2.Products.Add(new Product { Name = "苹果", Price = 2.5 });
                c2.Products.Add(new Product { Name = "香蕉", Price = 3.2 });
                Category c3 = new Category { Name = "蔬菜" };
                c3.Products.Add(new Product { Name = "菠菜", Price = 2.2 });
                c3.Products.Add(new Product { Name = "白菜", Price = 1.3 });

                _context.Categories.InsertOnSubmit(c1);
                _context.Categories.InsertOnSubmit(c2);
                _context.Categories.InsertOnSubmit(c3);

                _context.SubmitChanges();
            }
            else
            {
                /*
                 * DatabaseSchemaUpdater - 数据库结构更新器
                 *     DatabaseSchemaVersion - 数据库结构的版本
                 *     Execute() - 更新数据库结构和版本号
                 *     
                 * 数据库结构有改变时，用以下方法更新不同版本的数据库结构
                 *     AddColumn<T>(string columnPropertyName) - 为表 T 添加列 columnPropertyName
                 *     AddIndex<T>(string indexName) - 为表 T 添加索引 indexName
                 *     AddTable<T>() - 为数据库添加表 T
                 *     AddAssociation<T>(string associationPropertyName) - 为表 T 添加数据库关联 associationPropertyName
                 */

                DatabaseSchemaUpdater dbUpdater = _context.CreateDatabaseSchemaUpdater();

                if (dbUpdater.DatabaseSchemaVersion == 10)
                {
                    dbUpdater.AddColumn<Product>("UpdateTime");
                 
                    dbUpdater.DatabaseSchemaVersion = 11;
                    dbUpdater.Execute();
                }
            }
        }

        private ObservableCollection<Category> _categories;
        public ObservableCollection<Category> Categories
        {
            get { return _categories; }
            set
            {
                _categories = value;
                NotifyPropertyChanged("Categories");
            }
        }


        public event PropertyChangedEventHandler PropertyChanged;
        private void NotifyPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }
}

View层 - App.xaml

<Application 
    x:Class="Demo.App"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"       
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
    xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
    
    xmlns:localDatabaseViewModel="clr-namespace:Demo.LocalDatabase.ViewModel">

    <Application.Resources>

        <localDatabaseViewModel:MyViewModel x:Key="LocalDatabaseViewModel" />
        
    </Application.Resources>

</Application>

View层 - NewProduct.xaml

<phone:PhoneApplicationPage 
    x:Class="Demo.LocalDatabase.NewProduct"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
    xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    FontFamily="{StaticResource PhoneFontFamilyNormal}"
    FontSize="{StaticResource PhoneFontSizeNormal}"
    Foreground="{StaticResource PhoneForegroundBrush}"
    SupportedOrientations="Portrait" Orientation="Portrait"
    mc:Ignorable="d" d:DesignHeight="696" d:DesignWidth="480"
    shell:SystemTray.IsVisible="True"
    
    xmlns:toolkit="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone.Controls.Toolkit"
    DataContext="{Binding Source={StaticResource LocalDatabaseViewModel}}">
    
    <Grid x:Name="LayoutRoot" Background="Transparent">
        <StackPanel Orientation="Vertical">
            <TextBlock Text="Product Name"/>
            <TextBox x:Name="txtProductName"/>
            
            <TextBlock Text="Product Price"/>
            <TextBox x:Name="txtProductPrice"/>

            <TextBlock Text="Product Category"/>
            <toolkit:ListPicker x:Name="listPickerCategory" ItemsSource="{Binding Categories}" DisplayMemberPath="Name" />
        </StackPanel>
    </Grid>

    <phone:PhoneApplicationPage.ApplicationBar>
        <shell:ApplicationBar Mode="Default" IsVisible="True">
            <shell:ApplicationBarIconButton x:Name="btnConfirm" IconUri="/ApplicationBarDemo/Assets/appbar.check.rest.png" Text="确认" Click="btnConfirm_Click" />
            <shell:ApplicationBarIconButton x:Name="btnCancel" IconUri="/ApplicationBarDemo/Assets/appbar.cancel.rest.png" Text="取消" Click="btnCancel_Click" />
        </shell:ApplicationBar>
    </phone:PhoneApplicationPage.ApplicationBar>

</phone:PhoneApplicationPage>

View层 - NewProduct.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using Microsoft.Phone.Controls;

using Demo.LocalDatabase.ViewModel;
using Demo.LocalDatabase.Model;

namespace Demo.LocalDatabase
{
    public partial class NewProduct : PhoneApplicationPage
    {
        public NewProduct()
        {
            InitializeComponent();
        }

        private void btnConfirm_Click(object sender, EventArgs e)
        {
            double price = 0;
            if (!double.TryParse(txtProductPrice.Text, out price))
            {
                MessageBox.Show("价格必须是 double 型");
                return;
            }

            var vm = Application.Current.Resources["LocalDatabaseViewModel"] as MyViewModel;

            Product product = new Product()
            {
                Name = txtProductName.Text,
                Price = double.Parse(txtProductPrice.Text),
                Category = (Category)listPickerCategory.SelectedItem
            };

            vm.AddProduct(product);

            NavigationService.Navigate(new Uri("/LocalDatabase/Demo.xaml", UriKind.Relative));
        }

        private void btnCancel_Click(object sender, EventArgs e)
        {

        }
    }
}

View层 - Demo.xaml

<phone:PhoneApplicationPage 
    x:Class="Demo.LocalDatabase.Demo"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone"
    xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    FontFamily="{StaticResource PhoneFontFamilyNormal}"
    FontSize="{StaticResource PhoneFontSizeNormal}"
    Foreground="{StaticResource PhoneForegroundBrush}"
    SupportedOrientations="Portrait" Orientation="Portrait"
    mc:Ignorable="d" d:DesignHeight="696" d:DesignWidth="480"
    shell:SystemTray.IsVisible="True"
    
    DataContext="{Binding Source={StaticResource LocalDatabaseViewModel}}"
    xmlns:controls="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone.Controls">

    <phone:PhoneApplicationPage.Resources>
        <DataTemplate x:Key="item">
            <ListBox ItemsSource="{Binding Products}">
                <ListBox.ItemTemplate>
                    <DataTemplate>
                        <Grid Width="460" HorizontalAlignment="Center">
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition Width="5*" />
                                <ColumnDefinition Width="5*" />
                            </Grid.ColumnDefinitions>

                            <StackPanel Orientation="Horizontal" VerticalAlignment="Center">
                                <TextBlock Text="{Binding Name}" />
                                <TextBlock Text="{Binding Price}" Margin="10 0 0 0" />
                            </StackPanel>

                            <StackPanel Orientation="Horizontal" Grid.Column="1" HorizontalAlignment="Right">
                                <Button x:Name="btnDelete" Content="删除" Click="btnDelete_Click" />
                            </StackPanel>
                        </Grid>
                    </DataTemplate>
                </ListBox.ItemTemplate>
            </ListBox>
        </DataTemplate>
        <DataTemplate x:Key="header">
            <TextBlock Text="{Binding Name}" />
        </DataTemplate>
    </phone:PhoneApplicationPage.Resources>

    <Grid x:Name="LayoutRoot" Background="Transparent">
        <controls:Pivot x:Name="pivot"
            Title="产品列表" 
            ItemTemplate="{StaticResource item}" 
            HeaderTemplate="{StaticResource header}"
            ItemsSource="{Binding Categories}">
        </controls:Pivot>
    </Grid>

    <phone:PhoneApplicationPage.ApplicationBar>
        <shell:ApplicationBar Mode="Default" IsVisible="True">
            <shell:ApplicationBarIconButton x:Name="btnAddProduct" IconUri="/ApplicationBarDemo/Assets/appbar.add.rest.png" Text="添加产品" Click="btnAddProduct_Click" />
        </shell:ApplicationBar>
    </phone:PhoneApplicationPage.ApplicationBar>
</phone:PhoneApplicationPage>

View层 - Demo.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using Microsoft.Phone.Controls;
using Demo.LocalDatabase.ViewModel;
using Demo.LocalDatabase.Model;

namespace Demo.LocalDatabase
{
    public partial class Demo : PhoneApplicationPage
    {
        public Demo()
        {
            InitializeComponent();
        }

        private void btnAddProduct_Click(object sender, EventArgs e)
        {
            NavigationService.Navigate(new Uri("/LocalDatabase/NewProduct.xaml", UriKind.Relative));
        }

        private void btnDelete_Click(object sender, RoutedEventArgs e)
        {
            var vm = Application.Current.Resources["LocalDatabaseViewModel"] as MyViewModel;
            vm.DeleteProduct((sender as Button).DataContext as Product);
        }
    }
}

OK
[源码下载]