asp.net生成缩略图

asp.net生成缩略图

当我们要上传图片的时候，往往需要生成缩略图，以往我们要使用第三方控件才能完成。在asp.net中用下面方法轻松搞定 
<script language="VB" runat="server"> 
Sub Page_Load(sender As Object, e As EventArgs)

Dim image,aNewImage As System.Drawing.Image 
dim width,height,newwidth,newheight as integer 
Dim callb As System.Drawing.Image.GetThumbnailImageAbort

'生成缩略图 
image=System.Drawing.Image.FromFile(Server.MapPath("classpic/"+"rs1.jpg")) 
width=image.Width 
height=image.height 
if width>height then 
newwidth=110 
newheight=image.height/image.Width*newwidth 
else 
newheight=110 
newwidth=image.Width/image.height*newheight 
end if

aNewImage=image.GetThumbnailImage(newwidth,newheight,callb,new System.IntPtr()) 
aNewImage.Save(Server.MapPath("smallpic/"+"rs1.gif")) 
image.Dispose()

End Sub 
</script>