C#實現(xiàn)的上傳圖片、保存圖片、加水印、生成縮略圖功能示例

來源：本站原創(chuàng)|時間：2020-01-10|欄目：C#教程|點擊：次

本文實例講述了C#實現(xiàn)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(shè)備地普及，處理圖片、視頻等需求也變得越來越基礎(chǔ)，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(fù)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?。?lt;/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(shù)據(jù)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??！";
  }
}
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 + "\\" + DateTime.Now.Year + "\\" + DateTime.Now.Month + "\\" + DateTime.Now.Day + "\\");
    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 + "\\" + DateTime.Now.Year + "\\" + DateTime.Now.Month + "\\" + DateTime.Now.Day + "\\");
    string imageUrl = "/" + folderName + "/" + DateTime.Now.Year + "/" + DateTime.Now.Month + "/" + DateTime.Now.Day + "/";
    System.Drawing.Image.GetThumbnailImageAbort myCallback = new System.Drawing.Image.GetThumbnailImageAbort(GetFalse);
    //數(shù)據(jù)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 + "\\" + DateTime.Now.Year + "\\" + DateTime.Now.Month + "\\" + DateTime.Now.Day + "\\");
    string imageUrl = "/" + folderName + "/" + DateTime.Now.Year + "/" + DateTime.Now.Month + "/" + DateTime.Now.Day + "/";
    System.Drawing.Image.GetThumbnailImageAbort myCallback = new System.Drawing.Image.GetThumbnailImageAbort(GetFalse);
    //數(shù)據(jù)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(dāng)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(guān)于C#相關(guān)內(nèi)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(jié)》、《C#數(shù)據(jù)結(jié)構(gòu)與算法教程》、《C#面向?qū)ο蟪绦蛟O(shè)計入門教程》及《C#程序設(shè)計之線程使用技巧總結(jié)》

希望本文所述對大家C#程序設(shè)計有所幫助。

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