生成图片验证码的代码(vb.net版)
Imports
System
Imports
System.Data
Imports
System.Configuration
Imports
System.Web
Imports
System.Web.Security
Imports
System.Web.UI
Imports
System.Web.UI.WebControls
Imports
System.Web.UI.WebControls.WebParts
Imports
System.Web.UI.HtmlControls
Imports
System.IO
Imports
System.Drawing
'
生成图片验证码类
Public
Class
CreateImage
Public
Sub
CreateImage()
End Sub
Public
Shared
Sub
DrawImage()
Dim
img
As
CreateImage
=
New
CreateImage() HttpContext.Current.Session(
"
CheckCode
"
)
=
Global.CreateImage.RndNum(
4
) Global.CreateImage.CreateImages(HttpContext.Current.Session(
"
CheckCode
"
).ToString())
End Sub
'
'' <summary>
'
'' 生成验证图片
'
''</summary>
'
''<param name="checkCode">验证字符</param>
Public
Shared
Sub
CreateImages(
ByVal
checkCode
As
String
)
Dim
iwidth
As
Integer
=
CType
(checkCode.Length
*
13
,
Integer
)
Dim
image
As
System.Drawing.Bitmap
=
New
System.Drawing.Bitmap(iwidth,
25
)
Dim
g
As
Graphics
=
Graphics.FromImage(image) g.Clear(Color.White)
'
定义颜色
Dim
c
As
Color()
=
{Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple}
'
定义字体
Dim
font
As
String
()
=
{
"
Verdana
"
,
"
Microsoft Sans Serif
"
,
"
Comic Sans MS
"
,
"
Arial
"
,
"
宋体
"
}
Dim
rand
As
Random
=
New
Random()
Dim
i
As
Integer
=
0
Do
While
i
<
50
Dim
x
As
Integer
=
rand.Next(image.Width)
Dim
y
As
Integer
=
rand.Next(image.Height) g.DrawRectangle(
New
Pen(Color.LightGray,
0
), x, y,
1
,
1
) i
+=
1
Loop
i
=
0
Do
While
i
<
checkCode.Length
Dim
cindex
As
Integer
=
rand.Next(
7
)
Dim
findex
As
Integer
=
rand.Next(
5
)
Dim
f
As
Font
=
New
System.Drawing.Font(font(findex),
10
, System.Drawing.FontStyle.Bold)
Dim
b
As
Brush
=
New
System.Drawing.SolidBrush(c(cindex))
Dim
ii
As
Integer
=
4
If
(i
+
1
)
Mod
2
=
0
Then
ii
=
2
End
If
g.DrawString(checkCode.Substring(i,
1
), f, b,
3
+
(i
*
12
), ii) i
+=
1
Loop
'
画一个边框
g.DrawRectangle(
New
Pen(Color.Black,
0
),
0
,
0
, image.Width
-
1
, image.Height
-
1
)
Dim
ms
As
System.IO.MemoryStream
=
New
System.IO.MemoryStream() image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg) HttpContext.Current.Response.ClearContent() HttpContext.Current.Response.ContentType
=
"
image/Jpeg
"
HttpContext.Current.Response.BinaryWrite(ms.ToArray()) g.Dispose() image.Dispose()
End Sub
'
'' <summary>
'
'' 生成随机的字母
'
'' </summary>
'
'' <param name="VcodeNum">生成字母的个数</param>
'
'' <returns>string</returns>
Public
Shared
Function
RndNum(
ByVal
VcodeNum
As
Integer
)
As
String
Dim
allChar
As
String
=
"
0,1,2,3,4,5,6,7,8,9
"
Dim
allCharArray()
As
String
=
allChar.Split(
"
,
"
)
Dim
randomCode
As
String
=
""
Dim
temp
As
Integer
=
-
1
Dim
rand
As
Random
=
New
Random
Dim
i
As
Integer
=
0
Do
While
(i
<
VcodeNum)
If
(temp
<>
-
1
)
Then
Dim
aa
As
Integer
=
CType
(DateTime.Now.Ticks
Mod
System.Int32.MaxValue,
Integer
)
'
根据时间生成随机数种子
rand
=
New
Random(aa)
End
If
Dim
t
As
Integer
=
rand.Next(
61
)
+
1
If
t
>
allCharArray.Length
-
1
Then
t
=
allCharArray.Length
-
1
If
temp
=
t
Then
'
抑制产生连续重复的验证码。
i
-=
1
randomCode
=
Microsoft.VisualBasic.Left(randomCode, i)
End
If
temp
=
t randomCode
=
randomCode
+
allCharArray(t) i
+=
1
Loop
Return
randomCode
End Function
End Class
生成图片验证码,请指教!
转载于:https://www.cnblogs.com/wangxiang/archive/2007/06/25/795522.html
相关资源：ASP.NET五种验证码(VB.NET)
