Windows Phone实用开发技巧（1）：保存图片及加载图片

首先声明，本文章是转载：http://www.cnblogs.com/alexis/archive/2011/05/26/2052319.html

     wp7 sdk中文版出来一段时间了，由于最近比较忙，也没有去尝试下，经过一上午的整体配置，计算机终于可以顺利的跑 wp7项目了，呵呵，根据博客园这位老兄的日志，写了一个小程序，权作学习的开端。

   需求很简单，打开一幅图片，自定义背景图片，为了将程序下次打开的时候，能够不丢失图片，我们将其保存到手机内存中去，不罗嗦，直接晒demo:

 汗...博客园不让上传图片了...这么回事...好吧.先晒前台代码：

<phone:PhoneApplicationPage 
    x:Class="PhoneApp1SaveImg.MainPage"
    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"
    mc:Ignorable="d" d:DesignWidth="480" d:DesignHeight="768"
    FontFamily="{StaticResource PhoneFontFamilyNormal}"
    FontSize="{StaticResource PhoneFontSizeNormal}"
    Foreground="{StaticResource PhoneForegroundBrush}"
    SupportedOrientations="Portrait" Orientation="Portrait"
    shell:SystemTray.IsVisible="True">

    <!--LayoutRoot 是包含所有页面内容的根网格-->
    <Grid x:Name="LayoutRoot" Background="Transparent">
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>

        <!--TitlePanel 包含应用程序的名称和页标题-->
        <StackPanel x:Name="TitlePanel" Grid.Row="0" Margin="12,17,0,28">
            <TextBlock x:Name="ApplicationTitle" Text="我的第一个测试" Style="{StaticResource PhoneTextNormalStyle}"/>
            <TextBlock x:Name="PageTitle" Text="设置背景图片" Margin="9,-7,0,0" Style="{StaticResource PhoneTextTitle1Style}"/>
        </StackPanel>

        <!--ContentPanel - 在此处放置其他内容-->
        <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
            <Button Content="打开" Height="72" HorizontalAlignment="Left" Margin="134,58,0,0" Name="openImg" VerticalAlignment="Top" Width="160" Click="openImg_Click" />
            <Button Content="加载" Height="72" HorizontalAlignment="Left" Margin="134,170,0,0" Name="loadImg" VerticalAlignment="Top" Width="160" Click="loadImg_Click" />
        </Grid>
    </Grid>

</phone:PhoneApplicationPage>

后台代码：

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 Microsoft.Phone.Tasks;
using System.IO.IsolatedStorage;
using System.Windows.Media.Imaging;
using Microsoft.Phone;

namespace PhoneApp1SaveImg
{
    public partial class MainPage : PhoneApplicationPage
    {
        // 构造函数
        public MainPage()
        {
            InitializeComponent();
        }

        byte[] imageByte = null;

        //加载本地图片
        private void openImg_Click(object sender, RoutedEventArgs e)
        {
            //图片选择器
            PhotoChooserTask task = new PhotoChooserTask();
            task.Completed += new EventHandler<PhotoResult>(task_Completed);
            task.Show();
        }

        void task_Completed(object sender, PhotoResult e)
        {
            imageByte = new byte[e.ChosenPhoto.Length];
            e.ChosenPhoto.Read(imageByte, 0, imageByte.Length);
            //保存图片
            SaveToLocalStorage(imageByte, "myImg", "Images");
        }
        //将图片保存到本地
        public static void SaveToLocalStorage(byte[] _imageBytes, string imageFileName, string imageFolder)
        {
            if (_imageBytes == null)
            {
                return;
            }
            var isFile = IsolatedStorageFile.GetUserStoreForApplication();//获取独立存储空间
            if (!isFile.DirectoryExists(imageFolder))
            {
                isFile.CreateDirectory(imageFolder);
            }
            string filePath = System.IO.Path.Combine(imageFolder, imageFileName);
            using(var  sream=isFile.CreateFile(filePath))
            {
                sream.Write(_imageBytes,0,_imageBytes.Length); //写入文件
            }
        }
        //读取图片
        public static WriteableBitmap LoadImageFromLocalStorge(string imageFileName, string imageFolder)
        {
            var isFile = IsolatedStorageFile.GetUserStoreForApplication();
            if (!isFile.DirectoryExists(imageFolder))
            {
                isFile.CreateDirectory(imageFolder);
            }
            string filePath = System.IO.Path.Combine(imageFolder, imageFileName);
            using (var imageSream = isFile.OpenFile(filePath, System.IO.FileMode.Open, System.IO.FileAccess.Read))
            {
                //将图片转换成wirteableBitmap
                WriteableBitmap imageSource = PictureDecoder.DecodeJpeg(imageSream);
                return imageSource;
            }
        }
        //读取图片
        private void loadImg_Click(object sender, RoutedEventArgs e)
        {
             ImageBrush  myBrush=new ImageBrush();

             ContentPanel.Background = new ImageBrush()
             {
                  ImageSource=LoadImageFromLocalStorge("myImg", "Images")
             };
        }
    }
}

算了..睡觉了...不让发图片...闹心