在ASP.NET裡輕鬆實現縮圖 (轉)[@more@]

在裡輕鬆實現縮圖

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以前，在頁面上實現縮圖必須藉助第三方。現在，有了.NET，就可以很輕鬆地實現縮圖。下面就是實現縮圖的例子。

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程式碼如下：Thumbnail.aspx

.Thumbnail" %> w3c//DTD HTML 4.0 Transitional//EN"> <title>在裡輕鬆實現縮圖</title> <meta content="a href=" tag-126-1.html="">microsoft .NET 7.0" name="GENERATOR"> <meta content="a href=" tag-50-1.html=""> 7.0" name="CODE_LANGUAGE"> <meta content="a href=" tag-133-1.html="">script" name="vs_defaultClientScript"> <meta content=" href=" tag-340-1.html="">intellisense/" name="vs_targetSchema"> id="Form1" method="post" runat="server" enctype="multipart/form-data"> <input type="file" name="file" width="600"><br><br> gerStepThrough()> Private Sub InitializeComponent() End Sub Private Sub Page_Init(ByVal sender As System., ByVal e As System.EventArgs) Handles MyBase.Init 'CODEGEN: This method call is required by the Web Form Designer 'Do not modify it using the code editor. InitializeComponent() End Sub #End Region Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load Label1.Text = "<h3>在ASP.NET裡輕鬆實現縮圖</h3>" Button1.Text = "上載並顯示縮圖" End Sub Private Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click Dim MyFileColl As HttpFileCollection = HttpContext.Current.Request.Files Dim MyPostedFile As HttpPostedFile = MyFileColl.Item(0) If LCase(MyPostedFile.ContentType.ToString()).IndexOf("image") <0 then exit sub end if end sub private function as href="tag-73-1.html">select Case (strContentType.ToString().ToLower()) Case "image/pjpeg" GetImageType = System.Drawing.Imaging.ImageFormat.Jpeg Case "image/gif" GetImageType = System.Drawing.Imaging.ImageFormat.Gif Case "image/bmp" GetImageType = System.Drawing.Imaging.ImageFormat.Bmp Case "image/tiff" GetImageType = System.Drawing.Imaging.ImageFormat.Tiff Case "image/x-icon" GetImageType = System.Drawing.Imaging.ImageFormat.Icon Case "image/x-png" GetImageType = System.Drawing.Imaging.ImageFormat.Png Case "image/x-emf" GetImageType = System.Drawing.Imaging.ImageFormat.Emf Case "image/x-exif" GetImageType = System.Drawing.Imaging.ImageFormat.Exif Case "image/x-wmf" GetImageType = System.Drawing.Imaging.ImageFormat.Wmf Case Else GetImageType = System.Drawing.Imaging.ImageFormat.MemoryBmp End Select End Function Private Sub GetThumbNail(ByVal strFileName, ByVal iWidth, ByVal iheight, ByVal strContentType, _ ByVal blnGetFromFile, ByVal ImgStream) Dim oImg As Image If blnGetFromFile Then oImg = oImg.FromFile(strFileName) Else oImg = oImg.FromStream(ImgStream) End If oImg = oImg.GetThumbnailImage(iWidth, iheight, Nothing, (New IntPtr()).Zero) Dim strGuid As String = (New Guid()).NewGuid().ToString().ToUpper() Dim strFileExt As String = strFileName.Substring(strFileName.LastIndexOf(".")) '儲存到本地 'oImg.Save(Server.MapPath("images") + "" + strGuid + strFileExt, GetImageType(strContentType)) '直接輸出url 'Response.Redirect("images/" + strGuid + strFileExt) '以下顯示在螢幕上 Response.ContentType = strContentType Dim MemStream As New MemoryStream() ' 注意：這裡如果直接用 oImg.Save(Response.OutputStream, GetImageType(strContentType)) ' 對不同的格式可能會出錯，比如Png格式。 oImg.Save(MemStream, GetImageType(strContentType)) MemStream.WriteTo(Response.OutputStream) End Sub End Class

在ASP.NET裡輕鬆實現縮圖 (轉)

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