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用asp.net实现上传图片生成缩略图(代码)

献给大家一段用connection
dim mycomm as sqlcommand
dim sql as string
dim id as integer
Dim image,anewimage As System.Drawing.Image
dim width,height,newwidth,newheight as integer
Dim callb As System.Drawing.Image.GetThumbnailImageAbort
myConn=New sqlconnection(ConfigurationSettings.AppSettings("数据库"))
myconn.open()
sql="insert into picture (姓名,班级,介绍,属性) values ('"&request.cookies("dgxyl").values("dgxylname")&"','"&request.cookies("dgxyl").values("dgxylbj")&"','"&trim(request("TextBox1"))&"','"&request("r1")&"')"
Mycomm=New sqlcommand(sql,myconn)
mycomm.executenonquery()
myconn.close()

Dim myCommand As New SqlCommand("select top 1 id from picture order by id desc", myConn)
myCommand.Connection.Open()
Dim myReader As SqlDataReader=mycommand.executereader()
if myReader.Read() then
id=myReader("id")
end if
myconn.close()
'保存图片
FileUp.PostedFile.SaveAs( Server.MapPath("\classpic\")&cstr(id)&".jpg" )
'生成缩略图
image=System.Drawing.Image.FromFile(Server.MapPath("/classpic/"+cstr(id)+".jpg"))
width=image.Width
height=image.height
if width>height then
newwidth=250
newheight=image.height/image.Width*newwidth
else
newheight=250
newwidth=image.Width/image.height*newheight
end if
response.write("id="+cstr(id)+"width="+cstr(Width)+";height="+cstr(height)+"  ")
response.write("newwidth="+cstr(newwidth)+";newheight="+cstr(newheight)+"<br>")

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


Dim FileSplit() As String = Split( FileUp.PostedFile.FileName, "\" )
Dim FileName As String = FileSplit(FileSplit.Length-1)
Dim Exts() As String = Split( FileName, "." )
Dim Ext As String = LCase(Exts(Exts.Length-1))

FDisplay.Text = "<A Target='_blank' HREF='http://www.jzxue.com/classpic/"&cstr(id)&".jpg"& "'>查看上传文件</A>"
FDisplay1.text="<a href='/picture/default.asp?bj="&cstr(request.cookies("dgxyl").values("dgxylbj"))&"'>返回</a>"
End Sub
</script>
<SCRIPT language=>
<!--
var requestsubmitted=false;
function guestbook_Validator(theForm)
{
//检查是否从新提交
if (requestsubmitted==true){
  alert("你已经提交了留言,请等待服务器应答!");
  return(false);
}
requestsubmitted=true;

return (true);
}
//-->
</SCRIPT>
<Html>
<Body BgColor=White>
<H3 align="center">请正确填写下面各项</h3>
<Hr></H3>
<Div id="FileInfo" Visible="False" runat="server">
<Asp:Label id="FSize" runat="server"/><br>
<Asp:Label id="FName" runat="server"/><br>
<Asp:Label id="FDisplay" runat="server"/>
<Asp:Label id="FDisplay1" runat="server"/>
</Div>
<Form Enctype="multipart/form-data" onsubmit="return guestbook_Validator(this)" runat="server">
上传文件
<Input Type="File" id="FileUp" runat="server" size="20"><br>
图片属性:<input type="radio" value="<%=request.cookies("dgxyl").values("dgxylbj")%>" name="R1" checked>本班<input type="radio" value="全校" name="R1">全校(本班则只在本班显示,全校则在全校显示)<P>
图片说明:<br>
<asp:TextBox id="TextBox1" runat="server" Width="233px" Height="141px">
</asp:TextBox>
        <asp:RequiredFieldValidator id="RequiredFieldValidator1" runat="server" ControlToValidate="TextBox1" ErrorMessage="请输入图片说明">
</asp:RequiredFieldValidator><br>
<Asp:button id="Upload" OnClick="UploadFile" Text="上传图片" runat="server"/>
</form>
</Body>
</Html>