C#上传图片 并按尺寸新生成一张略缩图

上传图片并生成略缩图

参数说明
FileBox:上传表单中的表单名
SavePath:保存路径
ThumbnailWidth:略缩图宽
ThumbnailHeight:略缩图高
FilePath:文件保存路径（输出参数）
FileName:文件名称（输出参数）
LastError:（输出错误）
public static bool UploadImages(System.Web.UI.HtmlControls.HtmlInputFile FileBox,string SavePath,Int32 ThumbnailWidth,Int32 ThumbnailHeight,out String FilePath,out String FileName,out string LastError)
{
DateTime datTime=System.DateTime.Now;
String strTemp;
string strFileName = FileBox.PostedFile.FileName;
bool blnResult;
LastError="";
System.Drawing.Image xImage;
System.Drawing.Bitmap xBitmap;
int PhotoHeight,PhotoWidth;
string BasePath=System.Web.HttpContext.Current.Server.MapPath("../");
Rectangle NewPhoto;
System.Drawing.Imaging.ImageFormat xObject;
string Extension="";
FileName="";
FilePath="";

try
{
if(strFileName=="")
{
LastError="请点击浏览选择要上传的文件!";
return false;
}
if(Convert.ToDecimal(FileBox.PostedFile.ContentLength)<= 2000000 &&Convert.ToDecimal(FileBox.PostedFile.ContentLength)>1500)
{
//查看扩展名是否合法
Extension=Path.GetExtension(strFileName);
Extension=Extension.ToLower();
if(Extension==".gif" || Extension==".jpg" || Extension==".jpeg" || Extension==".bmp")
{
switch(Extension)
{
case ".gif":
xObject=System.Drawing.Imaging.ImageFormat.Gif;
break;
case ".bmp":
xObject=System.Drawing.Imaging.ImageFormat.Bmp;
break;
default:
xObject=System.Drawing.Imaging.ImageFormat.Jpeg;

break;
}
}
else
{
LastError="上传的文件不是有效的图片文件，请上传格式为：.gif.jpg.bmp的文件！";
return false;
}
//-----------------------------
//生成保存的文件路径及文件名
//-----------------------------
strTemp = datTime.ToShortDateString().Replace( "-", "");
FileName = datTime.ToLongTimeString().Replace(":","")+ Extension;
FilePath = SavePath + strTemp + "/";
Friendlib.Function.CreateDirectory(BasePath + FilePath);
//保存大图
xImage=System.Drawing.Bitmap.FromStream(FileBox.PostedFile.InputStream);

xImage.Save(BasePath+FilePath+FileName);
xImage.Dispose();
//-----------------------------
//开始生成缩略图
//-----------------------------
xBitmap=new Bitmap(BasePath+FilePath+FileName);//------------------

PhotoHeight=xBitmap.Height;
PhotoWidth=xBitmap.Width;
// //判断图片的形状
if(Convert.ToDecimal(PhotoHeight)/Convert.ToDecimal(PhotoWidth)>Convert.ToDecimal(ThumbnailHeight)/Convert.ToDecimal(ThumbnailWidth))//高有余
{
PhotoHeight=Convert.ToInt16((Convert.ToDecimal(ThumbnailHeight)/Convert.ToDecimal(ThumbnailWidth))*Convert.ToDecimal(PhotoWidth));
NewPhoto=new Rectangle(0,0,PhotoWidth,PhotoHeight);
}
else if(Convert.ToDecimal(PhotoHeight)/Convert.ToDecimal(PhotoWidth)<Convert.ToDecimal(ThumbnailHeight)/Convert.ToDecimal(ThumbnailWidth))
{
PhotoWidth=Convert.ToInt16((Convert.ToDecimal(ThumbnailWidth)/Convert.ToDecimal(ThumbnailHeight))*Convert.ToDecimal(PhotoHeight));
NewPhoto=new
Rectangle(Convert.ToInt16((Convert.ToDecimal(xBitmap.Width)-Convert.ToDecimal(PhotoWidth))/2),0,PhotoWidth,PhotoHeight);
}
else
{
NewPhoto= newRectangle(0,0,PhotoWidth,PhotoHeight); < BR> }
System.Drawing.Image myBitmap;
myBitmap=xBitmap.Clone(NewPhoto,System.Drawing.Imaging.PixelFormat.DontCare);
System.Drawing.Image.GetThumbnailImageAbort myCallback = new
System.Drawing.Image.GetThumbnailImageAbort(ThumbnailCallback);
System.Drawing.Image myThumbnail =
myBitmap.GetThumbnailImage(ThumbnailWidth,ThumbnailHeight, myCallback,
IntPtr.Zero); myThumbnail.Save(BasePath + FilePath +"s"+FileName,xObject);
myThumbnail.Dispose(); myBitmap.Dispose(); xBitmap.Dispose(); return true; }
else
{
blnResult=false; LastError="不能上传大于2M及小于1.5K的图片!";
}
}< BR> catch (Exception ex) {
throw new System.Exception((ex.Message + ("/r/n" + ex.StackTrace)));
}
return blnResult;
}
private static bool ThumbnailCallback() { return false; }