| asp.net生成缩略图代码实例(可按百分比和按大小两种方式) |
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发布时间:2007-12-25 发布人:
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缩略图代码: ImageThumbnail.cs using System; using System.IO; using System.Drawing; using System.Drawing.Imaging;public class ImageThumbnail { public Image ResourceImage; private int ImageWidth; private int ImageHeight; public string ErrorMessage;
public ImageThumbnail(string ImageFileName) { ResourceImage = Image.FromFile(ImageFileName); ErrorMessage = ""; }
public bool ThumbnailCallback() { return false; }
// 方法1,按大小 public bool ReducedImage(int Width, int Height, string targetFilePath) { try { Image ReducedImage; Image.GetThumbnailImageAbort callb = new Image.GetThumbnailImageAbort(ThumbnailCallback); ReducedImage = ResourceImage.GetThumbnailImage(Width, Height, callb, IntPtr.Zero); ReducedImage.Save(@targetFilePath, ImageFormat.Jpeg); ReducedImage.Dispose(); return true; } catch (Exception e) { ErrorMessage = e.Message; return false; } }
// 方法2,按百分比 缩小60% Percent为0.6 targetFilePath为目标路径 public bool ReducedImage(double Percent, string targetFilePath) { try { Image ReducedImage; Image.GetThumbnailImageAbort callb = new Image.GetThumbnailImageAbort(ThumbnailCallback); ImageWidth = Convert.ToInt32(ResourceImage.Width * Percent); ImageHeight = (ResourceImage.Height)*ImageWidth/ ResourceImage.Width;//等比例缩放 ReducedImage = ResourceImage.GetThumbnailImage(ImageWidth, ImageHeight, callb, IntPtr.Zero); ReducedImage.Save(@targetFilePath, ImageFormat.Jpeg); ReducedImage.Dispose(); return true; } catch (Exception e) { ErrorMessage = e.Message; return false; } }
}
后台代码: using System; using System.Data; using System.Configuration; using System.Collections; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Web.UI.HtmlControls; public partial class _Default : System.Web.UI.Page {
protected void Page_Load(object sender, EventArgs e) {
} protected void bt_upload_Click(object sender, EventArgs e) { try { if (FileUpload1.PostedFile.FileName == "") { this.lb_info.Text = "请选择文件!"; } else { string filepath = FileUpload1.PostedFile.FileName; string filename = filepath.Substring(filepath.LastIndexOf("\\") + 1); string serverpath1 = Server.MapPath("images/") + filename; string serverpath2 = Server.MapPath("images/") + System.DateTime.Now.ToString("yyy-MM-dd-hh-mm-ss") + Session.SessionID + filename; FileUpload1.PostedFile.SaveAs(serverpath1); ImageThumbnail img = new ImageThumbnail(filepath); img.ReducedImage(0.4, serverpath2);//0.4表示缩小40% this.lb_info.Text = "上传成功!"; } } catch (Exception error) { this.lb_info.Text = "上传发生错误!原因:" + error.ToString(); } } }
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