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

2014-02-22 19:08 267 查看
原文:与众不同 windows phone (7) - Local Database（本地数据库）[索引页]
[源码下载]

[align=center]与众不同 windows phone (7) - Local Database（本地数据库）[/align]

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
*/
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
*/

[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]

                        
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