1. 把WPF image 压缩为字符串并保存在XML中
2. 把XML中的字符串解压为WPF image
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
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;
using System.IO.Compression;
using System.IO;
using System.Xml;
using System.Runtime.Serialization.Formatters.Binary;
namespace WpfAppByteZipTest
{
/// <summary>
/// MainWindow.xaml 的交互逻辑
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
string imageFile = @"C:\Documents and Settings\Administrator\My Documents\My Pictures\11.jpg";
// BitmapImage imgSource = new BitmapImage(new Uri(imageFile, UriKind.Absolute));
byte[] b = GetPictureData(imageFile);
BitmapImage myimg = ByteArrayToBitmapImage(b);
image1.Source = myimg;
}
/// <summary>
/// 将字节数组进行压缩后返回压缩的字节数组
/// </summary>
/// <param name="data">需要压缩的数组</param>
/// <returns>压缩后的数组</returns>
public static byte[] Compress(byte[] data)
{
MemoryStream stream = new MemoryStream();
GZipStream gZipStream = new GZipStream(stream, CompressionMode.Compress);
gZipStream.Write(data, 0, data.Length);
gZipStream.Close();
return stream.ToArray();
}
/// <summary>
/// 解压字符数组
/// </summary>
/// <param name="data">压缩的数组</param>
/// <returns>解压后的数组</returns>
public static byte[] Decompress(byte[] bytes)
{
using (MemoryStream tempMs = new MemoryStream())
{
using (MemoryStream ms = new MemoryStream(bytes))
{
GZipStream Decompress = new GZipStream(ms, CompressionMode.Decompress);
Decompress.CopyTo(tempMs);
Decompress.Close();
return tempMs.ToArray();
}
}
}
public static string Compress(string str)
{
//因输入的字符串不是Base64所以转换为Base64,因为HTTP如果不传递Base64则会发生http 400错误
return Convert.ToBase64String(Compress(Convert.FromBase64String(Convert.ToBase64String(Encoding.Default.GetBytes(str)))));
}
public byte[] GetPictureData(string imagepath)
{
try
{
/**/
////根据图片文件的路径使用文件流打开,并保存为byte[]
FileStream fs = new FileStream(imagepath, FileMode.Open);//可以是其他重载方法
byte[] byData = new byte[fs.Length];
fs.Read(byData, 0, byData.Length);
fs.Close();
return byData;
}
catch (System.Exception e)
{
MessageBox.Show(e.Message);
return null;
}
}
private static BitmapImage ByteArrayToBitmapImage(byte[] byteArray)
{
BitmapImage bmp = null;
try
{
bmp = new BitmapImage();
bmp.BeginInit();
bmp.StreamSource = new MemoryStream(byteArray);
bmp.EndInit();
}
catch
{
bmp = null;
}
return bmp;
}
private static byte[] BitmapImageToByteArray(BitmapImage bmp)
{
byte[] byteArray = null;
try
{
Stream sMarket = bmp.StreamSource;
if (sMarket != null && sMarket.Length > 0)
{
//很重要,因为Position经常位于Stream的末尾,导致下面读取到的长度为0。
sMarket.Position = 0;
using (BinaryReader br = new BinaryReader(sMarket))
{
byteArray = br.ReadBytes((int)sMarket.Length);
}
}
}
catch
{
//other exception handling
}
return byteArray;
}
string fileXmlPath = @"C:\Documents and Settings\Administrator\My Documents\bytetest.xml";
/// <summary>
/// 压缩保存为XML
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnWrite_Click(object sender, RoutedEventArgs e)
{
BitmapImage imgSource = image1.Source as BitmapImage;
byte[] imageByte = BitmapImageToByteArray(imgSource);
byte[] sourceData2 = Compress(imageByte);
string recString = Convert.ToBase64String(sourceData2);
WriteXML(fileXmlPath, recString);
}
public static string ToHexString(byte[] bytes) // 0xae00cf => "AE00CF "
{
string hexString = string.Empty;
if (bytes != null)
{
StringBuilder strB = new StringBuilder();
for (int i = 0; i < bytes.Length; i++)
{
strB.Append(bytes[i].ToString("X2"));
}
hexString = strB.ToString();
}
return hexString;
}
//反过来,16进制格式的string 转成byte[],例如, "ae00cf"转换成0xae00cf,长度缩减一半;"3031" 转成new byte[]{ 0x30, 0x31}:
public static byte[] GetBytes(string hexString, out int discarded)
{
discarded = 0;
string newString = "";
char c;
// remove all none A-F, 0-9, characters
for (int i=0; i<hexString.Length; i++)
{
c = hexString[i];
if (Uri.IsHexDigit(c))
newString += c;
else
discarded++;
}
// if odd number of characters, discard last character
if (newString.Length % 2 != 0)
{
discarded++;
newString = newString.Substring(0, newString.Length-1);
}
int byteLength = newString.Length / 2;
byte[] bytes = new byte[byteLength];
string hex;
int j = 0;
for (int i=0; i<bytes.Length; i++)
{
hex = new String(new Char[] {newString[j], newString[j+1]});
bytes[i] = HexToByte(hex);
j = j+2;
}
return bytes;
}
private static byte HexToByte(string hex)
{
byte tt = byte.Parse(hex, System.Globalization.NumberStyles.HexNumber);
return tt;
}
public void WriteXML(string FileName, string imageData)
{
XmlDocument doc = new XmlDocument();
XmlElement Root = doc.CreateElement("Root");//主内容
doc.AppendChild(Root);
XmlElement Child1 = doc.CreateElement("attr1");
XmlAttribute attr1 = doc.CreateAttribute("attr1");
attr1.Value = imageData;
Child1.Attributes.Append(attr1);
Root.AppendChild(Child1);
doc.Save(FileName);//保存这个xml 网页或exe 都可以
}
private void btnRead_Click(object sender, RoutedEventArgs e)
{
XmlDocument doc = new XmlDocument();
doc.Load(fileXmlPath);
XmlNode root = doc.SelectSingleNode("Root");
if (root == null)
return;
XmlNode Child1 = root.SelectSingleNode("attr1");
if (Child1 == null)
return;
if (Child1.Attributes["attr1"] != null)
{
string hexValue = Child1.Attributes["attr1"].Value;
byte[] imageByte = Convert.FromBase64String(hexValue);
imageByte = Decompress(imageByte);
BitmapImage imgSource = ByteArrayToBitmapImage(imageByte);
image2.Source = imgSource;
}
}
}
}
<Window x:Class="WpfAppByteZipTest.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="346" Width="531">
<Grid >
<Button Content="压缩保存为XML字符串" Height="23" HorizontalAlignment="Left" Margin="54,272,0,0" Name="button1" VerticalAlignment="Top" Width="151" Click="btnWrite_Click" />
<Button Content="从XML读并解压图像数据" Height="23" HorizontalAlignment="Left" Margin="270,272,0,0" Name="button2" VerticalAlignment="Top" Width="162" Click="btnRead_Click" />
<Image Height="239" HorizontalAlignment="Left" Margin="270,12,0,0" Name="image2" Stretch="Fill" VerticalAlignment="Top" Width="227" />
<Image Height="239" HorizontalAlignment="Left" Margin="12,12,0,0" Name="image1" Stretch="Fill" VerticalAlignment="Top" Width="243" />
</Grid>
</Window>
本文介绍了如何将WPF Image对象压缩成字符串,并存储在XML文件中,以及如何从XML文件中读取字符串解压缩回WPF Image的过程。
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