asp.net 在ashx文件中读写session
asp.net 在ashx文件中读写session
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终于搞定在ashx中输出验证码，在保存验证码时竟然读不到session
错误提示：未将对象引用设置到对象的实例。
查找资料终于搞定....
首先要继承 System.Web.SessionState.IReadOnlySessionState 的接口
其中：System.Web.SessionState.IReadOnlySessionState为只读会话的接口
而：System.Web.SessionState.IRequiresSessionState 为可读可写会话的接口，这个看情况而继承吧～～～
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1
using
System;
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3
using
System.Collections.Generic;
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using
System.Linq;
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using
System.Web;
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using
System.Drawing;
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using
System.Web.UI.WebControls;
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using
System.Web.SessionState;
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namespace
CanYou.FinancePlat.Web
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{
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///
<summary>
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///
GeneraLoginCode 的摘要说明
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///
</summary>
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public
class
GeneraLoginCode : IHttpHandler, IRequiresSessionState
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{
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public
void
ProcessRequest(HttpContext context)
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{
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string
checkCode
=
CreateCode(
4
);
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context.Response.Cache.SetCacheability(HttpCacheability.NoCache);
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context.Session[
"
_Login_ValidateCode
"
]
=
checkCode;
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CreateImage(checkCode, context);
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}
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private
string
CreateCode(
int
codeLength)
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{
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string
so
=
"
1,2,3,4,5,6,7,8,9,0,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z
"
;
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string
[] strArr
=
so.Split(
'
,
'
);
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string
code
=
""
;
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Random rand
=
new
Random();
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for
(
int
i
=
0
; i
<
codeLength; i
++
)
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{
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code
+=
strArr[rand.Next(
0
, strArr.Length)];
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}
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return
code;
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}
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private
void
CreateImage(
string
code, HttpContext context)
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{
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Bitmap image
=
new
Bitmap(
60
,
20
);
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Graphics g
=
Graphics.FromImage(image);
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WebColorConverter ww
=
new
WebColorConverter();
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g.Clear((Color)ww.ConvertFromString(
"
#FAE264
"
));
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Random random
=
new
Random();
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//
画图片的背景噪音线
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for
(
int
i
=
0
; i
<
12
; i
++
)
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{
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int
x1
=
random.Next(image.Width);
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int
x2
=
random.Next(image.Width);
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int
y1
=
random.Next(image.Height);
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int
y2
=
random.Next(image.Height);
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g.DrawLine(
new
Pen(Color.LightGray), x1, y1, x2, y2);
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}
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Font font
=
new
Font(
"
Arial
"
,
15
, FontStyle.Bold
|
FontStyle.Italic);
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System.Drawing.Drawing2D.LinearGradientBrush brush
=
new
System.Drawing.Drawing2D.LinearGradientBrush(
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new
Rectangle(
0
,
0
, image.Width, image.Height), Color.Blue, Color.Gray,
1.2f
,
true
);
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g.DrawString(code, font, brush,
0
,
0
);
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//
画图片的前景噪音点
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for
(
int
i
=
0
; i
<
10
; i
++
)
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{
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int
x
=
random.Next(image.Width);
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int
y
=
random.Next(image.Height);
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image.SetPixel(x, y, Color.White);
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}
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//
画图片的边框线
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g.DrawRectangle(
new
Pen(Color.Silver),
0
,
0
, image.Width
-
1
, image.Height
-
1
);
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System.IO.MemoryStream ms
=
new
System.IO.MemoryStream();
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image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
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context.Response.ClearContent();
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context.Response.ContentType
=
"
image/Gif
"
;
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context.Response.BinaryWrite(ms.ToArray());
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g.Dispose();
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image.Dispose();
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}
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public
bool
IsReusable
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{
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get
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{
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return
false
;
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}
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}
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}
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}