asp.net 验证码生成和刷新及验证
1 新建VerifyCode.aspx
cs文件代码如下:
using System; using System.Collections; using System.ComponentModel; using System.Data; using System.Web; using System.Web.SessionState; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.HtmlControls; using System.Drawing; using System.Drawing.Imaging; using System.Drawing.Text; /**///// <summary> /// 页面验证码程序 /// 使用:在页面中加入HTML代码 <img src="VerifyCode.aspx"> /// </summary> public partial class VerifyCode : System.Web.UI.Page ...{ static string[] FontItems = new string[] ...{ "Arial", "Helvetica", "Geneva", "sans-serif", "Verdana" }; static Brush[] BrushItems = new Brush[] ...{ Brushes.OliveDrab, Brushes.ForestGreen, Brushes.DarkCyan, Brushes.LightSlateGray, Brushes.RoyalBlue, Brushes.SlateBlue, Brushes.DarkViolet, Brushes.MediumVioletRed, Brushes.IndianRed, Brushes.Firebrick, Brushes.Chocolate, Brushes.Peru, Brushes.Goldenrod }; static string[] BrushName = new string[] ...{ "OliveDrab", "ForestGreen", "DarkCyan", "LightSlateGray", "RoyalBlue", "SlateBlue", "DarkViolet", "MediumVioletRed", "IndianRed", "Firebrick", "Chocolate", "Peru", "Goldenrod" }; private static Color BackColor = Color.White; private static Pen BorderColor = Pens.DarkGray; private static int Width = 52; private static int Height = 21; private Random _random; private string _code; private int _brushNameIndex; 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); } /**//// <summary> /// /// </summary> /// <param name="sender"></param> /// <param name="e"></param> public void Page_Load(object sender, System.EventArgs e) ...{ if (!IsPostBack) ...{ // // TODO : initialize // this._random = new Random(); this._code = GetRandomCode(); // // TODO : use Session["code"] save the VerifyCode // Session["code"] = this._code; // // TODO : output Image // this.SetPageNoCache(); this.OnPaint(); } } /**//**//**//// <summary> /// 设置页面不被缓存 /// </summary> private void SetPageNoCache() ...{ Response.Buffer = true; Response.ExpiresAbsolute = System.DateTime.Now.AddSeconds(-1); Response.Expires = 0; Response.CacheControl = "no-cache"; Response.AppendHeader("Pragma","No-Cache"); } /**//**//**//// <summary> /// 取得一个 4 位的随机码 /// </summary> /// <returns></returns> private string GetRandomCode() ...{ return Guid.NewGuid().ToString().Substring(0, 4); } /**//**//**//// <summary> /// 随机取一个字体 /// </summary> /// <returns></returns> private Font GetFont() ...{ int fontIndex = _random.Next(0, FontItems.Length); FontStyle fontStyle = GetFontStyle(_random.Next(0, 2)); return new Font(FontItems[fontIndex], 12, fontStyle); } /**//**//**//// <summary> /// 取一个字体的样式 /// </summary> /// <param name="index"></param> /// <returns></returns> private FontStyle GetFontStyle(int index) ...{ switch (index) ...{ case 0: return FontStyle.Bold; case 1: return FontStyle.Italic; default: return FontStyle.Regular; } } /**//**//**//// <summary> /// 随机取一个笔刷 /// </summary> /// <returns></returns> private Brush GetBrush() ...{ int brushIndex = _random.Next(0, BrushItems.Length); _brushNameIndex = brushIndex; return BrushItems[brushIndex]; } /**//**//**//// <summary> /// 绘画事件 /// </summary> private void OnPaint() ...{ Bitmap objBitmap = null; Graphics g = null; try ...{ objBitmap = new Bitmap(Width, Height); g = Graphics.FromImage(objBitmap); Paint_Background(g); Paint_Text(g); Paint_TextStain(objBitmap); Paint_Border(g); objBitmap.Save(Response.OutputStream, ImageFormat.Gif); Response.ContentType = "image/gif"; } catch ...{} finally ...{ if (null != objBitmap) objBitmap.Dispose(); if (null != g) g.Dispose(); } } /**//**//**//// <summary> /// 绘画背景颜色 /// </summary> /// <param name="g"></param> private void Paint_Background(Graphics g) ...{ g.Clear(BackColor); } /**//**//**//// <summary> /// 绘画边框 /// </summary> /// <param name="g"></param> private void Paint_Border(Graphics g) ...{ g.DrawRectangle(BorderColor, 0, 0, Width - 1, Height - 1); } /**//**//**//// <summary> /// 绘画文字 /// </summary> /// <param name="g"></param> private void Paint_Text(Graphics g) ...{ g.DrawString(_code, GetFont(), GetBrush(), 3, 1); } /**//**//**//// <summary> /// 绘画文字噪音点 /// </summary> /// <param name="g"></param> private void Paint_TextStain(Bitmap b) ...{ for (int n=0; n<30; n++) ...{ int x = _random.Next(Width); int y = _random.Next(Height); b.SetPixel(x, y, Color.FromName(BrushName[_brushNameIndex])); } } }
2 页面引用:
<asp:Image ID="getcode" src="VerifyCode.aspx" runat="server" />
一般需要同时提供刷新功能(看不清楚换一张),代码如下
<asp:Image ID="getcode" src="VerifyCode.aspx" runat="server" /> <A href="javascript:getimgcode()">刷新验证码</A>
如使用了母版页,则用如下代码:
<img ID="getcode" alt="" src="VerifyCode.aspx" /> <%--<asp:Image ID="getcode" src="VerifyCode.aspx" runat="server" />--%>
<A href="javascript:getimgcode()">刷新验证码</A>
超链接对应的javascript如下:
<script language="javascript" type="text/javascript">
function getimgcode()
{
var getimagecode = document.getElementById("getcode");
getimagecode.src = "VerifyCode.aspx";
}
</script>
3 判断验证
上述代码是将验证码存贮在Session中,用code来标志。读取代码Session["code"].ToString();
使用中,我们只需要比较Session["code"].ToString()和文本框输入的串(TextBoxCode.Text)是否相同即可进行判断。
if(Session["code"].ToString().Trim().Equals(TextBoxCode.Text.Trim()))
...{
Response.Write("Success");
}
测试通过!
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