在ASP.NET中上传图片并生成缩略图

privatevoidbtnUploadPicture_Click(objectsenderSystemEventArgse)

{

//检查上传文件的格式是否有效

if(thisUploadFilePostedFileContentTypeToLower()IndexOf(image)<)

{

ResponseWrite(上传图片格式无效！);

return;

}

//生成原图

Byte[]oFileByte=newbyte[thisUploadFilePostedFileContentLength];

SystemIOStreamoStream=thisUploadFilePostedFileInputStream;

SystemDrawingImageoImage=SystemDrawingImageFromStream(oStream);

intoWidth=oImageWidth;//原图宽度

intoHeight=oImageHeight;//原图高度

inttWidth=;//设置缩略图初始宽度

inttHeight=;//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)

{

tHeight=(int)MathFloor(ConvertToDouble(oHeight)*(ConvertToDouble(tWidth)/ConvertToDouble(oWidth)));

}

else

{

tWidth=(int)MathFloor(ConvertToDouble(oWidth)*(ConvertToDouble(tHeight)/ConvertToDouble(oHeight)));

}

//生成缩略原图

BitmaptImage=newBitmap(tWidthtHeight);

Graphicsg=GraphicsFromImage(tImage);

gInterpolationMode=SystemDrawingDrawingDInterpolationModeHigh;//设置高质量插值法

gSmoothingMode=SystemDrawingDrawingDSmoothingModeHighQuality;//设置高质量低速度呈现平滑程度

gClear(ColorTransparent);//清空画布并以透明背景色填充

gDrawImage(oImagenewRectangle(tWidthtHeight)newRectangle(oWidthoHeight)GraphicsUnitPixel);

stringoFullName=ServerMapPath()+/+o+DateTimeNowToShortDateString()Replace()+DateTimeNowHourToString()+DateTimeNowMinuteToString()+DateTimeNowSecondToString()+DateTimeNowMillisecondToString()+jpg;//保存原图的物理路径

stringtFullName=ServerMapPath()+/+t+DateTimeNowToShortDateString()Replace()+DateTimeNowHourToString()+DateTimeNowMinuteToString()+DateTimeNowSecondToString()+DateTimeNowMillisecondToString()+jpg;//保存缩略图的物理路径

try

{

//以JPG格式保存图片

oImageSave(oFullNameSystemDrawingImagingImageFormatJpeg);

tImageSave(tFullNameSystemDrawingImagingImageFormatJpeg);

}

catch(Exceptionex)

{

throwex;

}

finally

{

//释放资源

oImageDispose();

gDispose();

tImageDispose();

}

}