MVC3.0 上传图片并生成缩略图

转自：http://mikelai.blog.163.com/blog/static/18411126620118771732675/

Controller:

public ActionResult Upload()

{

return View();

}

[HttpPost]

public ActionResult Upload(HttpPostedFileBase file)

{

var ostream = file.InputStream;

var orimage = Image.FromStream(ostream);

int owidth = orimage.Width; //原图宽度

int oheight = orimage.Height; //原图高度

int objwidth = 100; //设置缩略图初始宽度

int objheight = 100; //设置缩略图初始高度

//按比例计算出缩略图的宽度和高度

if (owidth >= oheight)

{

objheight = (int)Math.Floor(Convert.ToDouble(oheight) * (Convert.ToDouble(objwidth) / Convert.ToDouble(owidth)));

}

else

{

objwidth = (int)Math.Floor(Convert.ToDouble(owidth) * (Convert.ToDouble(objheight) / Convert.ToDouble(oheight)));

}

Bitmap objimage = new Bitmap(objwidth, objheight);

Graphics graphics = Graphics.FromImage(objimage);

graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High; //设置高质量插值法

graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;//设置高质量,低速度呈现平滑程度

graphics.Clear(Color.Transparent); //清空画布并以透明背景色填充

graphics.DrawImage(orimage, new Rectangle(0, 0, objwidth, objheight), new Rectangle(0, 0, owidth, oheight), GraphicsUnit.Pixel);

 

//rewrite imagename

var extensionName = Path.GetExtension(file.FileName);

var oriname = "ori" + DateTime.Now.ToString("yyyyMMddHHmmss") + extensionName;

var objname = "obj" + DateTime.Now.ToString("yyyyMMddHHmmss") + ".png";

 

var orifilePath = Path.Combine(HttpContext.Server.MapPath("/content/videos"), Path.GetFileName(oriname));

var objfilePath= Path.Combine(HttpContext.Server.MapPath("/content/videos"), Path.GetFileName(objname));

try

{

file.SaveAs(orifilePath);

objimage.Save(objfilePath, System.Drawing.Imaging.ImageFormat.Png);

}

 

catch (Exception ex)

{

throw ex;

}

finally

{

//释放资源

orimage.Dispose();

graphics.Dispose();

objimage.Dispose();

}

 

return RedirectToAction("Index");

}

 

View:

@using (Html.BeginForm("Upload", "Admin", FormMethod.Post, new { enctype = "multipart/form-data" }))

{

<label>

Filename:</label>

<input type="file" name="file" />

<input type="submit" value="Submit" />

}