简单验证码的产生

来源：互联网发布：淘宝店哪些东西利润高编辑：程序博客网时间：2024/04/30 11:51

1.建立ValidateCode.aspx页面cs代码

public class ValidateCode : System.Web.UI.Page

{

private void Page_Load(object sender, System.EventArgs e)

{

//如果要在页面a.aspx生成验证码，则在该页面添加一个图片控件，假设命名为：Image1，然后在page_Load事件中写如下代码：

//ImageButton1.ImageUrl = "ValidateCode.aspx";

//这样就可以生成验证码了，ValidateCode.aspx页面可以随便放在哪里，不过要注意Image1.src 要写对，同级可以直接写ValidateCode.aspx，上一级写../ValidateCode.aspx，很方便吧。

if(!IsPostBack)

{

//RndNum是一个自定义函数

//这里的数字4代表显示的是4位的验证字符串！

//string VNum=RndNum(4);

string VNum=GenerateRandom(4);

Session["VNum"] = VNum;

Validate_Code(VNum);

}

Web Form Designer generated code

private void Validate_Code(string VNum)

{

int Gheight=(int)(VNum.Length * 11.5);

//gheight为图片宽度,根据字符长度自动更改图片宽度

System.Drawing.Bitmap Img = new System.Drawing.Bitmap(Gheight,20);

Graphics g = Graphics.FromImage(Img);

g.DrawString(VNum,new System.Drawing.Font("Arial",10),new System.Drawing.SolidBrush(Color.Red),3,3);

//在矩形内绘制字串（字串，字体，画笔颜色，左上x.左上y）

System.IO.MemoryStream ms=new System.IO.MemoryStream();

Img.Save(ms,System.Drawing.Imaging.ImageFormat.Png);

Response.ClearContent(); //需要输出图象信息要修改HTTP头

Response.ContentType="image/Png";

Response.BinaryWrite(ms.ToArray());

g.Dispose();

Img.Dispose();

Response.End();

}

private static char[] constant=

{

'0','1','2','3','4','5','6','7','8','9',

'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'

};

public static string GenerateRandom(int Length)

{

System.Text.StringBuilder newRandom = new System.Text.StringBuilder(62);

Random rd= new Random();

for(int i=0;i<Length;i++)

{

newRandom.Append(constant[rd.Next(62)]);

}

return newRandom.ToString();

}

2.建立演示页面Login.aspx,html代码

<HTML>

<HEAD>

<title>Login</title>

</HEAD>

<body>

</col>

</col>

</col>

</colgroup>

<tr>

</col>

</col>

</col>

</col>

</colgroup>

<TR>

<TD align="right">LoginName</TD>

<TD>

<asp:TextBox id="txtLoginName" runat="server" Width="100%"></asp:TextBox></TD>

</TR>

<TR>

<TD align="right">Password</TD>

<TD>

<asp:TextBox id="txtPassword" runat="server" Width="100%"></asp:TextBox></TD>

</TR>

<TR>

<TD align="right">ValidateCode</TD>

<TD>

<asp:TextBox id="txtValidateCode" runat="server" Width="100%"></asp:TextBox></TD>

</TR>

<TR>

<TD>

<asp:Button id="Login" runat="server" Text="Login"></asp:Button>

<asp:Button id="Reset" runat="server" Text="Reset"></asp:Button></TD>

</TR>

</TABLE>

</td>

</tr>

</table>

</form>

</body>

</HTML>

3.Login页面的cs代码

public class Login : System.Web.UI.Page

{

protected System.Web.UI.WebControls.TextBox txtLoginName;

protected System.Web.UI.WebControls.TextBox txtPassword;

protected System.Web.UI.WebControls.TextBox txtValidateCode;

protected System.Web.UI.WebControls.Button Login;

protected System.Web.UI.WebControls.Button Reset;

protected System.Web.UI.WebControls.TextBox TextBox1;

private void Page_Load(object sender, System.EventArgs e)

{

if(Session["VNum"]!=null && Session["VNum"].ToString()==txtValidateCode.Text)

{

//验证码正确

}

Web Form Designer generated code

}