实例介绍
【实例简介】
【实例截图】
【核心代码】
Imports System.IO
Imports System.Collections
Public Class ImageViewer
' private member variables
Private mFolder As String
Private mImageList As ArrayList
Private mImagePosition As Integer
Private mPreviousImage As Image
Private mCurrentImage As Image
Private mNextImage As Image
''' <summary>
''' Default Constructor
''' </summary>
''' <remarks></remarks>
Public Sub New()
' This call is required by the Windows Form Designer.
InitializeComponent()
' Add any initialization after the InitializeComponent() call.
End Sub
''' <summary>
''' Default load event handler
''' </summary>
''' <param name="sender"></param>
''' <param name="e"></param>
''' <remarks></remarks>
Private Sub ImageViewer_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
' do nothing
End Sub
''' <summary>
''' Open the folder browse dialog and load
''' the initial images
''' </summary>
''' <param name="sender"></param>
''' <param name="e"></param>
''' <remarks></remarks>
Private Sub btnBrowse_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnBrowse.Click
' Label the folder browser dialog
Me.folderBrowserDialog1.Description = "Select the image directory."
' disable create folder feature of folder browser
Me.folderBrowserDialog1.ShowNewFolderButton = False
' display the folder browser
Dim result As DialogResult = folderBrowserDialog1.ShowDialog()
If result = DialogResult.OK Then
' on okay, set the image folder to the
' folder browser's selected path
mFolder = folderBrowserDialog1.SelectedPath
If (Not String.IsNullOrEmpty(mFolder)) Then
txtImageDirectory.Text = mFolder
Else
' exit if the user cancels
Return
End If
' initialize the image arraylist
mImageList = New ArrayList()
' loop through the image directory
' and find all of the image files
' add the found files to the image
' list - add other image types if
' necessary
Dim Dir As New DirectoryInfo(mFolder)
Dim f As FileInfo
For Each f In Dir.GetFiles("*.*")
Select Case (f.Extension.ToUpper())
Case ".JPG"
mImageList.Add(f.FullName)
Case ".BMP"
mImageList.Add(f.FullName)
Case ".GIF"
mImageList.Add(f.FullName)
Case Else
' skip file
End Select
Next
' set the starting position to 0
' and call the set images method
' to load the pictures
mImagePosition = 0
SetImages()
End If
End Sub
''' <summary>
''' This function is used to set the previous,
''' current, and next images into the
''' correct picture boxes
''' </summary>
''' <remarks></remarks>
Private Sub SetImages()
' clear any existing images
' memory will be an issue if
' cycling through a large
' number of images
mPreviousImage = Nothing
mNextImage = Nothing
mCurrentImage = Nothing
' set the previous image
If mImagePosition > 0 Then
Try
' set delegate
Dim prevCallback As Image.GetThumbnailImageAbort = _
New Image.GetThumbnailImageAbort(AddressOf ThumbnailCallback)
' get the previous image
Dim prevBmp As _
New Bitmap(mImageList(mImagePosition - 1).ToString())
' thumbnail the image to the size
' of the picture box
mPreviousImage = _
prevBmp.GetThumbnailImage(160, 100, _
prevCallback, IntPtr.Zero)
' set the picture box image
picPreviousImage.Image = mPreviousImage
' clear everything out
prevBmp = Nothing
prevCallback = Nothing
mPreviousImage = Nothing
Catch
'stall if it hangs, the user can retry
End Try
Else
' at the limit clear the
' image
picPreviousImage.Image = Nothing
End If
' set current image
If mImagePosition < mImageList.Count Then
Try
' set delegate
Dim currentCallback = _
New Image.GetThumbnailImageAbort(AddressOf ThumbnailCallback)
' get the current image
Dim currentBmp As _
New Bitmap(mImageList(mImagePosition).ToString())
' thumbnail the image to the size
' of the picture box
mCurrentImage = _
currentBmp.GetThumbnailImage(320, 200, currentCallback, IntPtr.Zero)
' set the picture box image
picCurrentImage.Image = mCurrentImage
' clear everything out
currentBmp = Nothing
mCurrentImage = Nothing
currentCallback = Nothing
Catch
'stall if it hangs, the user can retry
End Try
End If
' set next image
If mImagePosition < mImageList.Count - 1 Then
Try
' set delegate
Dim nextCallback As _
New Image.GetThumbnailImageAbort(AddressOf ThumbnailCallback)
' get the next image
Dim nextBmp As _
New Bitmap(mImageList(mImagePosition 1).ToString())
' thumbnail the image to the size
' of the picture box
mNextImage = _
nextBmp.GetThumbnailImage(160, 100, nextCallback, IntPtr.Zero)
' set the picture box image
picNextImage.Image = mNextImage
' clear everything out
nextBmp = Nothing
nextCallback = Nothing
mNextImage = Nothing
Catch
'stall if it hangs, the user can retry
End Try
Else
' at the limit clear the
' image
picNextImage.Image = Nothing
End If
' call for garbage collection
GC.Collect()
End Sub
''' <summary>
''' Thumbnail image abort target
''' </summary>
''' <returns></returns>
''' <remarks></remarks>
Public Function ThumbnailCallback() As Boolean
Return False
End Function
''' <summary>
''' Set the image position and reset all
''' of the images when the previous image
''' button is clicked
''' </summary>
''' <param name="sender"></param>
''' <param name="e"></param>
''' <remarks></remarks>
Private Sub btnPreviousImage_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnPreviousImage.Click
If (mImagePosition >= 0 And Not picPreviousImage.Image Is Nothing) Then
mImagePosition -= 1
SetImages()
End If
End Sub
''' <summary>
''' Set the image position and reset all
''' of the images when the next image
''' button is clicked
''' </summary>
''' <param name="sender"></param>
''' <param name="e"></param>
''' <remarks></remarks>
Private Sub btnNextImage_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnNextImage.Click
If (mImagePosition <= (mImageList.Count - 2)) Then
mImagePosition = 1
SetImages()
End If
End Sub
''' <summary>
''' Open the current image using the default
''' program per the user's file associations
''' </summary>
''' <param name="sender"></param>
''' <param name="e"></param>
''' <remarks></remarks>
Private Sub btnOpenImage_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnOpenImage.Click
System.Diagnostics.Process.Start(mImageList(mImagePosition).ToString())
End Sub
End Class
好例子网口号：伸出你的我的手 — 分享！
小贴士
感谢您为本站写下的评论，您的评论对其它用户来说具有重要的参考价值，所以请认真填写。
- 类似“顶”、“沙发”之类没有营养的文字，对勤劳贡献的楼主来说是令人沮丧的反馈信息。
- 相信您也不想看到一排文字/表情墙，所以请不要反馈意义不大的重复字符，也请尽量不要纯表情的回复。
- 提问之前请再仔细看一遍楼主的说明，或许是您遗漏了。
- 请勿到处挖坑绊人、招贴广告。既占空间让人厌烦，又没人会搭理，于人于己都无利。
关于好例子网
本站旨在为广大IT学习爱好者提供一个非营利性互相学习交流分享平台。本站所有资源都可以被免费获取学习研究。本站资源来自网友分享，对搜索内容的合法性不具有预见性、识别性、控制性，仅供学习研究，请务必在下载后24小时内给予删除，不得用于其他任何用途，否则后果自负。基于互联网的特殊性，平台无法对用户传输的作品、信息、内容的权属或合法性、安全性、合规性、真实性、科学性、完整权、有效性等进行实质审查；无论平台是否已进行审查，用户均应自行承担因其传输的作品、信息、内容而可能或已经产生的侵权或权属纠纷等法律责任。本站所有资源不代表本站的观点或立场，基于网友分享，根据中国法律《信息网络传播权保护条例》第二十二与二十三条之规定，若资源存在侵权或相关问题请联系本站客服人员，点此联系我们。关于更多版权及免责申明参见 版权及免责申明
网友评论
我要评论