Introduction
Here I will explain how to generate thumbnails dynamically from uploaded images and how to bind thumbnails to datalist using asp.net.
Description:
Now I will explain how to generate thumbnails from uploaded images and how to bind those thumbnails to datalist using asp.net. In website development sometimes we get requirement like generating thumbnails from images without losing quality of image and it’s same like original image. For that first create one new website after that right click on that website select New Folder give name as Images because here I am using same name if you want to use another name you need to change the name in code also. After completion of adding Images folder to your website Design your aspx page like this
| <html xmlns="http://www.w3.org/1999/xhtml"> <head id="Head1" runat="server"> <title>Generate a Thumbnails from Uploaded Image</title> </head> <body> <form id="form1" runat="server"> <div> <asp:FileUpload ID="fileupload1" runat="server" /> <asp:Button ID="btnsave" runat="server" Text="Upload" onclick="btnsave_Click" /> </div> <div> <asp:DataList ID="dtlist" runat="server" RepeatColumns="3" CellPadding="5"> <ItemTemplate> <asp:Image ID="Image1" ImageUrl='<%# Bind("Name", "~/Images/{0}") %>' runat="server" /> <br /> <asp:HyperLink ID="HyperLink1" Text='<%# Bind("Name") %>' NavigateUrl='<%# Bind("Name", "~/Images/{0}") %>' runat="server"/> </ItemTemplate> <ItemStyle BorderColor="Brown" BorderStyle="dotted" BorderWidth="3px" HorizontalAlign="Center" VerticalAlign="Bottom" /> </asp:DataList> </div> </form> </body> </html> |
After that add following namespaces in code behind
| using System.Collections; using System.Drawing; using System.Drawing.Drawing2D; using System.IO; |
After completion of adding namespaces write the following code
| protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { BindDataList(); } } protected void BindDataList() { DirectoryInfo dir = new DirectoryInfo(MapPath("Images")); FileInfo[] files = dir.GetFiles(); ArrayList listItems = new ArrayList(); foreach (FileInfo info in files) { listItems.Add(info); } dtlist.DataSource = listItems; dtlist.DataBind(); } protected void btnsave_Click(object sender, EventArgs e) { string filename = Path.GetFileName(fileupload1.PostedFile.FileName); string targetPath = Server.MapPath("Images/" + filename); Stream strm = fileupload1.PostedFile.InputStream; var targetFile = targetPath; //Based on scalefactor image size will vary GenerateThumbnails(0.07, strm, targetFile); BindDataList(); } private void GenerateThumbnails(double scaleFactor, Stream sourcePath, string targetPath) { using (var image = Image.FromStream(sourcePath)) { var newWidth = (int)(image.Width * scaleFactor); var newHeight = (int)(image.Height * scaleFactor); var thumbnailImg = new Bitmap(newWidth, newHeight); var thumbGraph = Graphics.FromImage(thumbnailImg); thumbGraph.CompositingQuality = CompositingQuality.HighQuality; thumbGraph.SmoothingMode = SmoothingMode.HighQuality; thumbGraph.InterpolationMode = InterpolationMode.HighQualityBicubic; var imageRectangle = new Rectangle(0, 0, newWidth, newHeight); thumbGraph.DrawImage(image, imageRectangle); thumbnailImg.Save(targetPath, image.RawFormat); } } |
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