.net core 生成驗證碼
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)
{
//驗證碼可以顯示的字元集合
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[] { ',' });//拆分成陣列
string code = "";//產生的隨機數
int temp = -1;//記錄上次隨機數值，儘量避避免生產幾個一樣的隨機數
Random rand = new Random();
//採用一個簡單的演算法以保證生成隨機數的不同
for (int i = 1; i<VcodeNum + 1; i++)
{
if (temp != -1)
{
rand = new Random(i* temp * unchecked((int) DateTime.Now.Ticks));//初始化隨機類
}
int t = rand.Next(61);//獲取隨機數
if (temp != -1 && temp == t)
{
return RndNum(VcodeNum);//如果獲取的隨機數重複，則遞迴呼叫
}
temp = t;//把本次產生的隨機數記錄起來
code += VcArray[t];//隨機數的位數加一
}
return code.ToLower();
}
/// <summary>
/// 該方法是將生成的隨機數寫入影象檔案
/// </summary>
/// <param name="code">code是一個隨機數</param>
/// <param name="numbers">生成位數（預設4位）</param>
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();
//驗證碼顏色集合
Color[] c = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };
//驗證碼字型集合
string[] fonts = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial", "宋體" };
//定義影象的大小，生成影象的例項
Img = new Bitmap((int) code.Length* 18, 32);
g = Graphics.FromImage(Img);//從Img物件生成新的Graphics物件
g.Clear(Color.White);//背景設為白色
//在隨機位置畫背景點
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);
}
//驗證碼繪製在g中
for (int i = 0; i<code.Length; i++)
{
int cindex = random.Next(7);//隨機顏色索引值
int findex = random.Next(5);//隨機字型索引值
Font f = new Font(fonts[findex], 15, FontStyle.Bold);//字型
Brush b = new SolidBrush(c[cindex]);//顏色
int ii = 4;
if ((i + 1) % 2 == 0)//控制驗證碼不在同一高度
{
ii = 2;
}
g.DrawString(code.Substring(i, 1), f, b, 3 + (i* 12), ii);//繪製一個驗證字元
}
ms = new MemoryStream();//生成記憶體流物件
Img.Save(ms, ImageFormat.Jpeg);//將此影象以Png影象檔案的格式儲存到流中
//回收資源
g.Dispose();
Img.Dispose();
return ms;
}
/// <summary>
/// 獲取驗證碼
/// </summary>
/// <param name="sessionKey">驗證碼存的Session的鍵</param>
/// <returns>返回一個驗證碼圖片</returns>
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");
}
}
/* 使用說明
* 在Startup類 ConfigureServices(IServiceCollection services) 方法中
* 註冊 session服務 (services.AddSession();) 在Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
* 中新增 session 配置 app.UseSession();
*
* 獲取驗證碼
* byte[] arryByte = null;
* HttpContext.Session.TryGetValue("loginVcode", out arryByte);
* string v = Common.ConvertCommon.ByteArryToString(arryByte);
* string v=HttpContextCommon.Current.Session.GetString(sessionKey);
*/
}