文章來自：https://blog.csdn.net/IT_xiao_guang_guang/article/details/104250015
一、功能界面
|
|
二、創建一個產生驗證碼的類Class1
（1）生成隨機驗證碼字符串，用的是Random隨機函數
（2）創建驗證碼圖片，將該字符串畫在PictureBox控件中
Class1.cs：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Drawing;//圖片
using System.Windows.Forms;
namespace ValidCodeTest
{
public class Class1
{
#region 驗證碼功能
/// <summary>
/// 生成隨機驗證碼字符串
/// </summary>
public static string CreateRandomCode(int CodeLength)
{
int rand;
char code;
string randomCode = String.Empty;//隨機驗證碼
//生成一定長度的隨機驗證碼
Random random = new Random();
for (int i = 0; i < CodeLength; i++)
{
rand = random.Next();
if (rand % 3 == 1)
{
code = (char)('A' + (char)(rand % 26));
}
else if (rand % 3 == 2)
{
code = (char)('a' + (char)(rand % 26));
}
else
{
code = (char)('0' + (char)(rand % 10));
}
randomCode += code.ToString();
}
return randomCode;
}
/// <summary>
/// 創建驗證碼圖片
/// </summary>
public static void CreateImage(string strValidCode, PictureBox pbox)
{
try
{
int RandAngle = 45;//隨機轉動角度
int MapWidth = (int)(strValidCode.Length * 21);
Bitmap map = new Bitmap(MapWidth, 28);//創建圖片背景
Graphics graph = Graphics.FromImage(map);
graph.Clear(Color.AliceBlue);//清除繪畫面,填充背景色
graph.DrawRectangle(new Pen(Color.Black, 0), 0, 0, map.Width - 1, map.Height - 1);//畫一個邊框
graph.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;//模式
Random rand = new Random();
//背景噪點生成
Pen blackPen = new Pen(Color.LightGray, 0);
for (int i = 0; i < 50; i++)
{
int x = rand.Next(0, map.Width);
int y = rand.Next(0, map.Height);
graph.DrawRectangle(blackPen, x, y, 1, 1);
}
//驗證碼旋轉，防止機器識別
char[] chars = strValidCode.ToCharArray();//拆散字符串成單字符數組
//文字居中
StringFormat format = new StringFormat(StringFormatFlags.NoClip);
format.Alignment = StringAlignment.Center;
format.LineAlignment = StringAlignment.Center;
//定義顏色
Color[] c = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };
//定義字體
string[] font = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial", "宋體" };
for (int i = 0; i < chars.Length; i++)
{
int cindex = rand.Next(7);
int findex = rand.Next(5);
Font f = new System.Drawing.Font(font[findex], 13, System.Drawing.FontStyle.Bold);//字體樣式(參數2為字體大小)
Brush b = new System.Drawing.SolidBrush(c[cindex]);
Point dot = new Point(16, 16);
float angle = rand.Next(-RandAngle, RandAngle);//轉動的度數
graph.TranslateTransform(dot.X, dot.Y);//移動光標到指定位置
graph.RotateTransform(angle);
graph.DrawString(chars[i].ToString(), f, b, 1, 1, format);
graph.RotateTransform(-angle);//轉回去
graph.TranslateTransform(2, -dot.Y);//移動光標到指定位置
}
pbox.Image = map;
}
catch (ArgumentException)
{
MessageBox.Show("驗證碼圖片創建錯誤");
}
}
#endregion
}
}
三、調用
（1）更新驗證碼
（2）驗證（區分大小寫）
（3）驗證（不區分大小寫）
Form1.cs：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using ValidCodeTest;
namespace ValidCode
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
#region 驗證碼
private const int ValidCodeLength = 4;//驗證碼長度
private String strValidCode = "";//驗證碼
//調用自定義函數,更新驗證碼
private void UpdateValidCode()
{
strValidCode = Class1.CreateRandomCode(ValidCodeLength);//生成隨機驗證碼
if (strValidCode == "") return;
Class1.CreateImage(strValidCode, pbox1);//創建驗證碼圖片
}
#endregion
private void pbox1_Click(object sender, EventArgs e)
{
UpdateValidCode();//點擊更新驗證碼
}
private void Form1_Load(object sender, EventArgs e)
{
UpdateValidCode();//加載更新驗證碼
}
/// <summary>
/// 驗證（區分大小寫）
/// </summary>
private void btn1_Click(object sender, EventArgs e)
{
string validcode = txtValidCode.Text.Trim();
char[] ch1 = validcode.ToCharArray();
char[] ch2 = strValidCode.ToCharArray();
int Count1 = 0;//字母個數
int Count2 = 0;//數字個數
if (String.IsNullOrEmpty(validcode) != true)//驗證碼不為空
{
for (int i = 0; i < strValidCode.Length; i++)
{
if ((ch1[i] >= 'a' && ch1[i] <= 'z') || (ch1[i] >= 'A' && ch1[i] <= 'Z'))//字母
{
if (ch1[i] == ch2[i])
{
Count1++;
}
}
else//數字
{
if (ch1[i] == ch2[i])
{
Count2++;
}
}
}
int CountSum = Count1 + Count2;
if (CountSum == strValidCode.Length)
{
MessageBox.Show("驗證通過", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
UpdateValidCode();
txtValidCode.Text = "";
txtValidCode.Focus();
}
else
{
MessageBox.Show("驗證失敗", "警告", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
UpdateValidCode();//更新驗證碼
txtValidCode.Text = "";
txtValidCode.Focus();
}
}
else//驗證碼為空
{
MessageBox.Show("請輸入驗證碼", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
UpdateValidCode();//更新驗證碼
txtValidCode.Text = "";
txtValidCode.Focus();
}
}
/// <summary>
/// 驗證（不區分大小寫）
/// </summary>
private void btn2_Click(object sender, EventArgs e)
{
string validcode = txtValidCode.Text.Trim();
if (String.IsNullOrEmpty(validcode) != true)//驗證碼不為空
{
if (validcode.ToLower() == strValidCode.ToLower())
{
MessageBox.Show("驗證通過", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
UpdateValidCode();
txtValidCode.Text = "";
txtValidCode.Focus();
}
else
{
MessageBox.Show("驗證失敗", "警告", MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
UpdateValidCode();//更新驗證碼
txtValidCode.Text = "";
txtValidCode.Focus();
}
}
else//驗證碼為空
{
MessageBox.Show("請輸入驗證碼", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
UpdateValidCode();//更新驗證碼
txtValidCode.Text = "";
txtValidCode.Focus();
}
}
}
}
.exe測試文件下載地址: https://www.lanzous.com/i984xva
密碼：test