利用.NET 框架下的FromBase64String和ToBase64String方法可以很容易地实现图象文件和XML文件的互换。这样可以轻易解决以XML格式保存图片的问题。代码如下：
Public Class Form1
Inherits System.Windows.Forms.Form
#Region " Windows 窗体设计器生成的代码 "
Public Sub New()
MyBase.New()
InitializeComponent()
'在 InitializeComponent() 调用之后添加任何初始化
End Sub
'窗体重写处置以清理组件列表。
Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
If disposing Then
If Not (components Is Nothing) Then
components.Dispose()
End If
End If
MyBase.Dispose(disposing)
End Sub
'Windows 窗体设计器所必需的
Private components As System.ComponentModel.IContainer
'注意：以下过程是 Windows 窗体设计器所必需的
'可以使用 Windows 窗体设计器修改此过程。
'不要使用代码编辑器修改它。
Friend WithEvents Button1 As System.Windows.Forms.Button
Friend WithEvents Button2 As System.Windows.Forms.Button
Friend WithEvents PictureBox1 As System.Windows.Forms.PictureBox
Friend WithEvents Button3 As System.Windows.Forms.Button
Friend WithEvents Label1 As System.Windows.Forms.Label
Friend WithEvents Label2 As System.Windows.Forms.Label
1<system.diagnostics.debuggerstepthrough()> Private Sub InitializeComponent()
2Me.Button1 = New System.Windows.Forms.Button()
3Me.Button2 = New System.Windows.Forms.Button()
4Me.PictureBox1 = New System.Windows.Forms.PictureBox()
5Me.Button3 = New System.Windows.Forms.Button()
6Me.Label1 = New System.Windows.Forms.Label()
7Me.Label2 = New System.Windows.Forms.Label()
8Me.SuspendLayout()
9'
10'Button1
11'
12Me.Button1.Location = New System.Drawing.Point(365, 63)
13Me.Button1.Name = "Button1"
14Me.Button1.Size = New System.Drawing.Size(115, 23)
15Me.Button1.TabIndex = 0
16Me.Button1.Text = "将图象保存成XML"
17'
18'Button2
19'
20Me.Button2.Location = New System.Drawing.Point(365, 98)
21Me.Button2.Name = "Button2"
22Me.Button2.Size = New System.Drawing.Size(115, 23)
23Me.Button2.TabIndex = 1
24Me.Button2.Text = "从XML中得到图象"
25'
26'PictureBox1
27'
28Me.PictureBox1.Location = New System.Drawing.Point(18, 6)
29Me.PictureBox1.Name = "PictureBox1"
30Me.PictureBox1.Size = New System.Drawing.Size(320, 460)
31Me.PictureBox1.TabIndex = 2
32Me.PictureBox1.TabStop = False
33'
34'Button3
35'
36Me.Button3.Location = New System.Drawing.Point(365, 28)
37Me.Button3.Name = "Button3"
38Me.Button3.Size = New System.Drawing.Size(115, 23)
39Me.Button3.TabIndex = 3
40Me.Button3.Text = "浏览图片…"
41'
42'Label1
43'
44Me.Label1.Location = New System.Drawing.Point(369, 135)
45Me.Label1.Name = "Label1"
46Me.Label1.Size = New System.Drawing.Size(105, 95)
47Me.Label1.TabIndex = 4
48'
49'Label2
50'
51Me.Label2.Location = New System.Drawing.Point(367, 437)
52Me.Label2.Name = "Label2"
53Me.Label2.Size = New System.Drawing.Size(130, 16)
54Me.Label2.TabIndex = 5
55Me.Label2.Text = "【孟宪会之精彩世界】"
56'
57'Form1
58'
59Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
60Me.ClientSize = New System.Drawing.Size(500, 480)
61Me.Controls.AddRange(New System.Windows.Forms.Control() {Me.Label2, Me.Label1, _
62Me.Button3, Me.PictureBox1, Me.Button2, Me.Button1})
63Me.Name = "Form1"
64Me.Text = "图象文件和XML格式文件互换例子"
65Me.ResumeLayout(False)
66
67End Sub
68
69#End Region
70
71Private MyFile As String = ""
72Private MyFileExt As String = ""
73Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) _
74Handles Button2.Click
75Dim pic As String
76Dim MyXml As System.Xml.XmlDocument = New System.Xml.XmlDocument()
77MyXml.Load("c:\MyPhoto.xml")
78Dim picNode As System.Xml.XmlNode
79picNode = MyXml.SelectSingleNode("/pic/photo")
80pic = picNode.InnerText
81Dim memoryStream As System.IO.MemoryStream
82memoryStream = New System.IO.MemoryStream(Convert.FromBase64String(pic))
83Me.PictureBox1.Image = New System.Drawing.Bitmap(memoryStream)
84memoryStream.Close()
85End Sub
86
87Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) _
88Handles Button1.Click
89If MyFile = "" Then
90MessageBox.Show("请选择一个图片！", "错误", MessageBoxButtons.OK, MessageBoxIcon.Warning)
91Exit Sub
92End If
93Dim MyImg As System.Drawing.Image = MyImg.FromFile(MyFile)
94Dim memoryStream As System.IO.MemoryStream = New System.IO.MemoryStream()
95MyImg.Save(memoryStream, GetImageType(MyFileExt))
96Dim b() As Byte
97b = memoryStream.GetBuffer()
98Dim pic As String = Convert.ToBase64String(b)
99memoryStream.Close()
100Dim MyXml As System.Xml.XmlDocument = New System.Xml.XmlDocument()
101MyXml.LoadXml("<pic><name>孟宪会</name><photo>" + pic + "</photo></pic>")
102MyXml.Save("c:\MyPhoto.xml")
103Label1.Text = "文件被保存到了：" + Microsoft.VisualBasic.ChrW(13) + "c:\MyPhoto.xml"
104End Sub
105
106Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) _
107Handles Button3.Click
108Dim openFileDialog1 As New OpenFileDialog()
109openFileDialog1.InitialDirectory = "c:\"
110openFileDialog1.Filter = "PNG(*.png)|*.png|Gif(*.gif)|*.gif|Jpg(*.jpg)|*.jpg|所有图象文件(*.*)|*.*"
111openFileDialog1.FilterIndex = 2
112openFileDialog1.RestoreDirectory = True
113If openFileDialog1.ShowDialog() = DialogResult.OK Then
114MyFile = openFileDialog1.FileName()
115MyFileExt = MyFile.Substring(MyFile.LastIndexOf(".") + 1)
116End If
117End Sub
118
119Public Function GetImageType(ByVal str As String) As System.Drawing.Imaging.ImageFormat
120Select Case str.ToLower()
121Case "jpg"
122Return System.Drawing.Imaging.ImageFormat.Jpeg
123Case "gif"
124Return System.Drawing.Imaging.ImageFormat.Gif
125Case "tiff"
126Return System.Drawing.Imaging.ImageFormat.Tiff()
127Case "icon"
128Return System.Drawing.Imaging.ImageFormat.Icon
129Case "image/png"
130Return System.Drawing.Imaging.ImageFormat.Png
131Case Else
132Return System.Drawing.Imaging.ImageFormat.MemoryBmp
133End Select
134End Function
135
136Private Sub Form1_Closing(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) _
137Handles MyBase.Closing
138System.Diagnostics.Process.Start("IExplore.exe", "http://xml.sz.luohuedu.net/")
139End Sub
140End Class</system.diagnostics.debuggerstepthrough()>