上传图片生成虽略图
上传(upload)文件的codebehind代码
功能：
1。把图片文件(JPG GIF PNG)上传，
2。保存到指定的路径（在web.config中设置路径，以文件的原有格式保存），
3。并自动生成指定宽度的（在web.config中设置宽度）
4。和指定格式的（在web.config中指定缩略图的格式）
5。和原图比例相同的缩略图(根据宽度和原图的宽和高计算所略图的高度)
6。可以判断是否已经存在文件
7。如果不覆盖，则给出错误
8。如果选中 "覆盖原图 "checkbox，则覆盖原图。
9。可以根据要求，在webform上设置1个以上的file input和相应的checkbox
10。并在文件上传完毕后，显示原图的文件名，尺寸，字节，和
11。缩略图的文件名尺寸。
12。缩略图的文件名格式：原图+ "_thumb. "+指定格式，如：test.jpg_thumb.gif,以便于管理。
--------------------
public void UploadFile(object sender, System.EventArgs e)
{
string imgNameOnly, imgNameNoExt, imgExt;
string imgThumbnail;
int erroNumber = 0;
System.Drawing.Image oriImg, newImg;
StringBuilder picInfo = new StringBuilder();
if(Page.IsValid)
{
for(int i = 0;i < Request.Files.Count; i++)
{
HttpPostedFile PostedFile = Request.Files[i];
string fileExt = (System.IO.Path.GetExtension(PostedFile.FileName)).ToString().ToLower();
imgNameOnly = System.IO.Path.GetFileName(PostedFile.FileName);
if(fileExt == ".jpg " || fileExt == ".gif " || fileExt == ".png ")
{
if(System.IO.File.Exists(ConfigurationSettings.AppSettings[ "FePicSavePath "]+ imgNameOnly) && (checkboxlistRewrite.Items[i].Selected == false))
{
erroNumber = erroNumber + 1;
picInfo.Append( " 错误： 文件( "+ (i+1) + ") " + imgNameOnly + " 已经存在，请修改文件名
" );
}
}
else
{
erroNumber = erroNumber + 1;
picInfo.Append( " 错误： 文件( "+ (i+1) + ") " + imgNameOnly + " 扩展名 " + fileExt + " 不被许可
" );
}
}
if(erroNumber > 0)
{
picInfo.Append( " 全部*作均未完成，请修改错误，再进行*作
");
}
else
{
for(int i = 0;i < Request.Files.Count
; i++)
{
HttpPostedFile PostedFile = Request.Files[i];
imgNameOnly = System.IO.Path.GetFileName(PostedFile.FileName);
imgNameNoExt = System.IO.Path.GetFileNameWithoutExtension(PostedFile.FileName);
imgExt = System.IO.Path.GetExtension(PostedFile.FileName).ToString().ToLower();
oriImg = System.Drawing.Image.FromStream(PostedFile.InputStream);
newImg = oriImg.GetThumbnailImage(Int32.Parse(ConfigurationSettings.AppSettings[ "FePicThumbWidth "]),Int32.Parse(ConfigurationSettings.AppSettings[ "FePicThumbWidth "])*oriImg.Height/oriImg.Width,null,new System.IntPtr(0));
switch(imgExt)
{
//case ".jpeg ":
case ".jpg ":
oriImg.Save(ConfigurationSettings.AppSettings[ "FePicSavePath "] + imgNameOnly , System.Drawing.Imaging.ImageFormat.Jpeg);
break;
case ".gif ":
oriImg.Save(ConfigurationSettings.AppSettings[ "FePicSavePath "] + imgNameOnly , System.Drawing.Imaging.ImageFormat.Gif);
break;
case ".png ":
oriImg.Save(ConfigurationSettings.AppSettings[ "FePicSavePath "] + imgNameOnly , System.Drawing.Imaging.ImageFormat.Png);
break;
}
//oriImg.Save(ConfigurationSettings.AppSettings[ "FePicSavePath "] + imgNameNoExt + ".jpg ", System.Drawing.Imaging.ImageFormat.Jpeg);
switch(ConfigurationSettings.AppSettings[ "FePicThumbFormat "].ToString().ToLower())
{
//jpeg format can get the smallest file size, and the png is the largest size
//case "jpeg ":
case "jpg ":
newImg.Save(ConfigurationSettings.AppSettings[ "FePicSavePath "] + imgNameOnly + "_thumb.jpg ",System.Drawing.Imaging.ImageFormat.Jpeg);
imgThumbnail = imgNameOnly + "_thumb.jpg ";
break;
case "gif ":
newImg.Save(ConfigurationSettings.AppSettings[ "FePicSavePath "] + imgNameOnly + "_thumb.gif ",System.Drawing.Imaging.ImageFormat.Gif);
imgThumbnail = imgNameOnly + "_thumb.gif ";
break;
case "png ":
newImg.Save(ConfigurationSettings.AppSettings[ "FePicSavePath "] + imgNameOnly + "_thumb.png ",System.Drawing.Imaging.ImageFormat.Png);
imgThumbnail = imgNameOnly + "_thumb.png ";
break;
default:
newImg.Save(ConfigurationSettings.AppSettings[ "FePicSavePath "] + imgNameOnly + "_thumb.jpg ",System.Drawing.Imaging.ImageFormat.Jpeg);
imgThumbnail = imgNameOnly + "_thumb.jpg ";
break;
}//switch
picInfo.Append( " 文件 名： " + imgNameOnly +
" ( " + oriImg.Width + " x " + oriImg.Height + " ) " + PostedFile.ContentLength/1024 + "KB
");
picInfo.Append( " 缩略图名： " + imgThumbnail + " ( " + newImg.Width + " x " + newImg.Height + " )
");
oriImg.Dispose();
newImg.Dispose();
}//for
picInfo.Append( " 所有*作成功
");
}// if erronumber = 0
}
else
{
picInfo.Append( " 有错误，请检查。*作未成功
");
}
lblPicInfo.Text = picInfo.ToString();
}