.net上传图片生成大小缩略图

public string GetSqlFile(FileUpload fp, int width, int height)

{

string sqlfile = "";

string tempSqlPath = "";

string path = HttpContext.Current.Request.PhysicalApplicationPath.ToString() + "upload/";

path += "UploadFile/" + DateTime.Now.ToString("yyyyMM");

tempSqlPath = "\\upload\\UploadFile\\" + DateTime.Now.ToString("yyyyMM");

if (Directory.Exists(path))

{

}

else

{

Directory.CreateDirectory(path);

}

if (Directory.Exists(path + "/small"))

{

}

else

{

Directory.CreateDirectory(path + "/small");

}

if (Directory.Exists(path + "/temp"))

{

}

else

{

Directory.CreateDirectory(path + "/temp");

}

//HttpFileCollection files = HttpContext.Current.Request.Files;

if (fp.FileName.ToString().Length > 0)

{

string filename = fp.FileName.ToString();

string datestr = DateTime.Now.ToString("yyyyMMddHmmssfff");

string ext = filename.Substring(filename.LastIndexOf(".")).ToLower();

if (ext != ".bmp" && ext != ".jpg" && ext != ".gif" && ext != ".jpeg")

{

HttpContext.Current.Response.Write("<script>alert('上传的文件不是.gif,jpg,jpeg,bmp格式')</script>");

return "";

}

string tempFilePath = path + "/" + "temp/" + datestr + ext;

fp.SaveAs(tempFilePath);

#region 生成小图

string originalFilename = path + "/" + datestr + ext;

//fp.FileBytes

//缩小的倍数

int iScale = 1;

//从文件取得图片对象

System.Drawing.Image image = null;

try

{

image = System.Drawing.Image.FromFile(tempFilePath);

}

catch

{

//

try

{

File.Delete(tempFilePath);

image.Dispose();

}

catch

{

}

HttpContext.Current.Response.Write("<script>alert('上传的文件不是.gif,jpg,jpeg,bmp图片的标准格式格式')</script>");

return "";

}

int hi = 0;

int wi = 0;

wi = width;

hi = height;

Size size = new Size(wi, hi);

//新建一个bmp图片

System.Drawing.Image bitmap = new Bitmap(size.Width, size.Height);

//新建一个画板

Graphics g = Graphics.FromImage(bitmap);

//设置高质量插值法

g.InterpolationMode = InterpolationMode.High;

//设置高质量,低速度呈现平滑程度

g.SmoothingMode = SmoothingMode.HighQuality;

//清空一下画布

g.Clear(Color.Blue);

//在指定位置画图

g.DrawImage(image, new Rectangle(0, 0, bitmap.Width, bitmap.Height), new Rectangle(0, 0, image.Width, image.Height), GraphicsUnit.Pixel);

if (ext == ".jpg" || ext == ".jpeg")

bitmap.Save(path + "/small/" + datestr + ext, ImageFormat.Jpeg);

if (ext == ".gif")

bitmap.Save(path + "/small/" + datestr + ext, ImageFormat.Gif);

if (ext == ".bmp")

bitmap.Save(path + "/small/" + datestr + ext, ImageFormat.Bmp);

///大图片

if (fp.FileBytes.Length > 300000){

//image.Width

// image.Height

wi = 800;

hi = Convert.ToInt32(image.Height * (Convert.ToDouble(wi) / Convert.ToDouble(image.Width)));

size = new Size(wi, hi);

//新建一个bmp图片

bitmap = new Bitmap(size.Width, size.Height);

//新建一个画板

g = Graphics.FromImage(bitmap);

//设置高质量插值法

g.InterpolationMode = InterpolationMode.High;

//设置高质量,低速度呈现平滑程度

g.SmoothingMode = SmoothingMode.HighQuality;

//清空一下画布

g.Clear(Color.Blue);

//在指定位置画图

g.DrawImage(image, new Rectangle(0, 0, bitmap.Width, bitmap.Height), new Rectangle(0, 0, image.Width, image.Height), GraphicsUnit.Pixel);

if (ext == ".jpg" || ext == ".jpeg")

bitmap.Save(originalFilename, ImageFormat.Jpeg);

if (ext == ".gif")

bitmap.Save(originalFilename, ImageFormat.Gif);

if (ext == ".bmp")

bitmap.Save(originalFilename, ImageFormat.Bmp);

}

else {

fp.SaveAs(originalFilename);

}

image.Dispose();

bitmap.Dispose();

g.Dispose();

#endregion

sqlfile = datestr + ext;

try

{

image.Dispose();

bitmap.Dispose();

g.Dispose();

File.Delete(tempFilePath);

}

catch (Exception ex)

{

string exc = ex.Message.ToString();

HttpContext.Current.Response.Write("<script>alert('" + exc + "');</script>");

}

}

else

{

sqlfile = "";

}

sqlfile = sqlfile.Length>0?(tempSqlPath + "\\" + sqlfile):("");

return sqlfile;

}