.net core 生成验证码

using Microsoft.AspNetCore.Http;

using Microsoft.AspNetCore.Mvc;

using System;

using System.Collections.Generic;

using System.DrawingCore;

using System.DrawingCore.Imaging;

using System.IO;

using System.Text;

namespace Common

{

public class VcodeCommon : Controller

{

private static string RndNum(int VcodeNum)

{

//验证码可以显示的字符集合

string Vchar = "0,1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,g,h,i,j,k,l,m,n,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,P,P,Q" +

",R,S,T,U,V,W,X,Y,Z";

string[] VcArray = Vchar.Split(new Char[] { ',' });//拆分成数组

string code = "";//产生的随机数

int temp = -1;//记录上次随机数值,尽量避避免生产几个一样的随机数

Random rand = new Random();

//采用一个简单的算法以保证生成随机数的不同

for (int i = 1; i

{

if (temp != -1)

{

rand = new Random(i* temp * unchecked((int) DateTime.Now.Ticks));//初始化随机类

}

int t = rand.Next(61);//获取随机数

if (temp != -1 && temp == t)

{

return RndNum(VcodeNum);//如果获取的随机数重复,则递归调用

}

temp = t;//把本次产生的随机数记录起来

code += VcArray[t];//随机数的位数加一

}

return code.ToLower();

}

 

///

/// 该方法是将生成的随机数写入图像文件

///

/// code是一个随机数

/// 生成位数(默认4位)

private static MemoryStream Create(out string code, int numbers = 4)

{

code = RndNum(numbers);

Bitmap Img = null;

Graphics g = null;

MemoryStream ms = null;

Random random = new Random();

//验证码颜色集合

Color[] c = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };

//验证码字体集合

string[] fonts = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial", "宋体" };

//定义图像的大小,生成图像的实例

Img = new Bitmap((int) code.Length* 18, 32);

g = Graphics.FromImage(Img);//从Img对象生成新的Graphics对象

g.Clear(Color.White);//背景设为白色

//在随机位置画背景点

for (int i = 0; i< 100; i++)

{

int x = random.Next(Img.Width);

int y = random.Next(Img.Height);

g.DrawRectangle(new Pen(Color.LightGray, 0), x, y, 1, 1);

}

//验证码绘制在g中

for (int i = 0; i

{

int cindex = random.Next(7);//随机颜色索引值

int findex = random.Next(5);//随机字体索引值

Font f = new Font(fonts[findex], 15, FontStyle.Bold);//字体

Brush b = new SolidBrush(c[cindex]);//颜色

int ii = 4;

if ((i + 1) % 2 == 0)//控制验证码不在同一高度

{

ii = 2;

}

g.DrawString(code.Substring(i, 1), f, b, 3 + (i* 12), ii);//绘制一个验证字符

}

ms = new MemoryStream();//生成内存流对象

Img.Save(ms, ImageFormat.Jpeg);//将此图像以Png图像文件的格式保存到流中

//回收资源

g.Dispose();

Img.Dispose();

return ms;

}


 

///

/// 获取验证码

///

/// 验证码存的Session的键

/// 返回一个验证码图片

public IActionResult Vcode(String sessionKey)

{

string code = "";

System.IO.MemoryStream ms =Create(out code);

//HttpContextCommon.Current.Session.Set(sessionKey, ConvertCommon.StringToByteArry(code));

HttpContextCommon.Current.Session.SetString(sessionKey, code);

HttpContextCommon.Current.Response.Body.Dispose();

return File(ms.ToArray(), @"image/png");

}


 

}

 

/* 使用说明

* 在Startup类 ConfigureServices(IServiceCollection services) 方法中

* 注册 session服务 (services.AddSession();) 在Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)

* 中添加 session 配置 app.UseSession();

*

* 获取验证码

* byte[] arryByte = null;

* HttpContext.Session.TryGetValue("loginVcode", out arryByte);

* string v = Common.ConvertCommon.ByteArryToString(arryByte);

* string v=HttpContextCommon.Current.Session.GetString(sessionKey);

*/

 

}

 

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