.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 /// 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); */ }