本文實例講述了C#實現的上傳圖片、保存圖片、加水印、生成縮略圖功能。分享給大家供大家參考，具體如下：
伴隨移動設備地普及，處理圖片、視頻等需求也變得越來越基礎，這里介紹的是圖片的存儲。
上傳圖片必須使用form表單提交的方式，我只知道這一種方法，如果大家知道其他方法的話請留言。
保存圖片、加水印和生成縮略圖這三種功能最好各自放在單獨的方法中，盡量降低耦合度，提高代碼復用程度，除此之外我們平常寫代碼是也要盡量做到方法功能的唯一性。
前臺代碼：
<form method="POST" enctype="multipart/form-data" action="UploadImg.ashx"> <table> <tr> <td>func：</td> <td><input type="text" name="func"/></td> </tr> <tr> <td>用戶Id：</td> <td><input type="text" name="userId"/></td> </tr> <tr> <td>頭像：</td> <td><input type="file" name="icon"/></td> </tr> <tr> <td>水印：</td> <td><input type="text" name="waterMark"/></td> </tr> </table> <input type="submit" value="提交"/></form>
后臺代碼：
private string UploadImage(HttpContext context){ try { System.IO.Stream stream = context.Request.Files["icon"].InputStream; //返回的圖片路徑可以存儲在數據庫中 string imageUrl = SaveImage(stream, "Icon", "蟈蟈"); string thumbnailImageUrl = SaveThumbnailImage(stream, "Icon"); string thumbnailImageUrlWithWatermark = SaveThumbnailImage(ConfigurationManager.AppSettings["AttachmentsDirectory"] + imageUrl, "Icon"); return "上傳成功！"; } catch (Exception ex) { return "上傳失敗！"; }}private string SaveImage(Stream stream, string folderName, string waterMark){ try { string fileName = Guid.NewGuid() + ".jpg"; string path = ConfigurationManager.AppSettings["AttachmentsDirectory"]; path = Path.Combine(path, folderName + "http://" + DateTime.Now.Year + "http://" + DateTime.Now.Month + "http://" + DateTime.Now.Day + "http://"); string imageUrl = "/" + folderName + "/" + DateTime.Now.Year + "/" + DateTime.Now.Month + "/" + DateTime.Now.Day + "/"; if (!string.IsNullOrEmpty(waterMark)) { Image imgSource = Image.FromStream(stream); AddWatermarkAndSave(path, fileName, waterMark, imgSource, imgSource.Height - 300, 10, Color.Red, new Font("宋體", 40)); } else { byte[] buffer = new byte[stream.Length]; stream.Read(buffer, 0, buffer.Length); if (!Directory.Exists(path)) { Directory.CreateDirectory(path); } System.IO.FileStream fs = new System.IO.FileStream(path + fileName, System.IO.FileMode.OpenOrCreate, System.IO.FileAccess.Write); fs.Write(buffer, 0, buffer.Length); fs.Flush(); fs.Close(); } return imageUrl + fileName; } catch (Exception ex) { return ""; }}private string SaveThumbnailImage(Stream stream, string folderName){ try { string fileName = Guid.NewGuid() + ".jpg"; string path = ConfigurationManager.AppSettings["AttachmentsDirectory"]; path = Path.Combine(path, folderName + "http://" + DateTime.Now.Year + "http://" + DateTime.Now.Month + "http://" + DateTime.Now.Day + "http://"); string imageUrl = "/" + folderName + "/" + DateTime.Now.Year + "/" + DateTime.Now.Month + "/" + DateTime.Now.Day + "/"; System.Drawing.Image.GetThumbnailImageAbort myCallback = new System.Drawing.Image.GetThumbnailImageAbort(GetFalse); //數據源來自Stream Image image = System.Drawing.Bitmap.FromStream(stream); System.Drawing.Image thumbnailImage = image.GetThumbnailImage(64, 64, myCallback, IntPtr.Zero); thumbnailImage.Save(path + fileName); thumbnailImage.Dispose(); return imageUrl + fileName; } catch (Exception ex) { return ""; }}private string SaveThumbnailImage(string originalFileName, string folderName){ try { string fileName = Guid.NewGuid() + ".jpg"; string path = ConfigurationManager.AppSettings["AttachmentsDirectory"]; path = Path.Combine(path, folderName + "http://" + DateTime.Now.Year + "http://" + DateTime.Now.Month + "http://" + DateTime.Now.Day + "http://"); string imageUrl = "/" + folderName + "/" + DateTime.Now.Year + "/" + DateTime.Now.Month + "/" + DateTime.Now.Day + "/"; System.Drawing.Image.GetThumbnailImageAbort myCallback = new System.Drawing.Image.GetThumbnailImageAbort(GetFalse); //數據源來自File Image image = System.Drawing.Bitmap.FromFile(originalFileName); System.Drawing.Image thumbnailImage = image.GetThumbnailImage(64, 64, myCallback, IntPtr.Zero); thumbnailImage.Save(path + fileName); thumbnailImage.Dispose(); return imageUrl + fileName; } catch (Exception ex) { return ""; }}private bool GetFalse(){ return false;}/// <summary>/// 圖片加文字水印/// </summary>/// <param name="fileName"> </param>/// <param name="text">水印文字，如果是多行用分號隔開</param>/// <param name="img">圖片</param>/// <param name="paddingTop">上邊距</param>/// <param name="paddingLeft">左邊距</param>/// <param name="textColor">文字顏色</param>/// <param name="textFont">字體</param>/// <param name="path">保存地址</param>/// <returns></returns>private bool AddWatermarkAndSave(string path, string fileName, string text, Image img, int paddingTop, int paddingLeft, Color textColor, Font textFont){ text = text + ";" + "當前時間：" + DateTime.Now.ToString("yyyy-MM-dd HH:mm"); if (!Directory.Exists(path)) { Directory.CreateDirectory(path); } textFont = new Font("宋體", 19); Bitmap bm = new Bitmap(img); System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bm); System.Drawing.Brush b = new SolidBrush(textColor); string[] str = text.Split(';'); for (int i = 0; i < str.Length; i++) g.DrawString(str[i], textFont, b, paddingLeft, paddingTop + 33 * i); g.Dispose(); bm.Save(path + fileName, ImageFormat.Jpeg); bm.Dispose(); return true;}更多關于C#相關內容感興趣的讀者可查看本站專題：《C#圖片操作技巧匯總》、《C#常見控件用法教程》、《WinForm控件用法總結》、《C#數據結構與算法教程》、《C#面向對象程序設計入門教程》及《C#程序設計之線程使用技巧總結》
希望本文所述對大家C#程序設計有所幫助。
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