产生验证码(图片)
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#region Web Form Designer generated code
override protected void OnInit(EventArgs e)
{
//
// CODEGEN: This call is required by the ASP.NET Web Form Designer.
//
InitializeComponent();
base.OnInit(e);
}
/**//// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
this.Load += new System.EventHandler(this.Page_Load);
}
#endregion
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>
<meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
<meta name="CODE_LANGUAGE" Content="C#">
<meta name="vs_defaultClientScript" content="JavaScript">
<meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
</HEAD>
<body>
<form id="Form1" method="post" runat="server">
<table align="center" cellSpacing="0" cellPadding="0" width="100%" border="0" height="100%">
<colgroup>
<col width="30%">
</col>
<col width="40%">
</col>
<col width="30%">
</col>
</colgroup>
<tr>
<td></td>
<td valign="middle">
<TABLE id="Table1" align="center" cellSpacing="0" cellPadding="0" width="100%" border="0">
<colgroup>
<col width="20%">
</col>
<col width="35%">
</col>
<col width="25%">
</col>
<col width="20%">
</col>
</colgroup>
<TR>
<TD align="right">LoginName</TD>
<TD>
<asp:TextBox id="txtLoginName" runat="server" Width="100%"></asp:TextBox></TD>
<td></td>
<td></td>
</TR>
<TR>
<TD align="right">Password</TD>
<TD>
<asp:TextBox id="txtPassword" runat="server" Width="100%"></asp:TextBox></TD>
<td></td>
<td></td>
</TR>
<TR>
<TD align="right">ValidateCode</TD>
<TD>
<asp:TextBox id="txtValidateCode" runat="server" Width="100%"></asp:TextBox></TD>
<td><IMG alt="" src="Pages/Wonderful/Form/ValidateCode.aspx"></td>
<td></td>
</TR>
<TR>
<TD></TD>
<TD>
<asp:Button id="Login" runat="server" Text="Login"></asp:Button>
<asp:Button id="Reset" runat="server" Text="Reset"></asp:Button></TD>
<td></td>
<td></td>
</TR>
</TABLE>
</td>
<td></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#region Web Form Designer generated code
override protected void OnInit(EventArgs e)
{
//
// CODEGEN: This call is required by the ASP.NET Web Form Designer.
//
InitializeComponent();
base.OnInit(e);
}
/**//// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
this.Load += new System.EventHandler(this.Page_Load);
}
#endregion
}
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