方法一：
public string CreateRandomCode(int codeCount)
{
string allChar = "0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,a,b,c,d,e,f,g,h,i,g,k,l,m,n,o,p,q,r,F,G,H,I,G,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z,s,t,u,v,w,x,y,z";
string[] allCharArray = allChar.Split(',');
string randomCode = ""; //声明随机字符串变量
int temp = -1;
Random rand = new Random(); //声明随机数对象
for (int i = 0; i < codeCount; i++)
{
if (temp != -1)
{
rand = new Random(i * temp * ((int)DateTime.Now.Ticks));
}
int t = rand.Next(35);
if (temp == t)
{
return CreateRandomCode(codeCount);
}
temp = t;
randomCode += allCharArray[t];
}
return randomCode;
}
方法二：
private static string GetRandomString(int length)
{
return Guid.NewGuid().ToString("N").Substring((32 - length), length);
}
二、创建验证码图片
实现方法一：
public byte[] CreateValidateGraphic(string validateCode)
{
//声明用于处理由像素数据定义的图像的对象（宽，高）
Bitmap image = new Bitmap((int)Math.Ceiling(validateCode.Length * 16.0), 27);
Graphics g = Graphics.FromImage(image);
try
{
Random random = new Random();
g.Clear(Color.White); //清空图片背景色
//画图片的干扰线
for (int i = 0; i < 25; i++)
{
int x1 = random.Next(image.Width);
int x2 = random.Next(image.Width);
int y1 = random.Next(image.Height);
int y2 = random.Next(image.Height);
g.DrawLine(new Pen(Color.Silver), x1, x2, y1, y2);
}
Font font = new Font("Arial", 14, (FontStyle.Bold | FontStyle.Italic)); //设置字体样式和大小
LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);
g.DrawString(validateCode, font, brush, 3, 2); //绘制指定的字符串
//画图片的前景干扰线
for (int i = 0; i < 100; i++)
{
int x = random.Next(image.Width);
int y = random.Next(image.Height);
image.SetPixel(x, y, Color.FromArgb(random.Next()));
}
g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1); //画图片的边框线
//保存图片数据
MemoryStream stream = new MemoryStream();
image.Save(stream, ImageFormat.Jpeg);
//输出图片流
return stream.ToArray();
}
finally
{
g.Dispose();
image.Dispose();
}
}
实现方法二：
![]()
/// <summary>
/// 由随机字符串，随即颜色背景，和随机线条产生的Image
/// </summary>
/// <returns>Image</returns>
public static byte[] GetVcodeImg(string text, int width = 200, int height = 45, int fontSize = 20)
//返回 Image
{
int charNum = text.Length;
//声明一个位图对象
Bitmap bitMap = null;
//声明一个绘图画面
Graphics gph = null;
//创建内存流
MemoryStream memStream = new MemoryStream();
Random random = new Random();
//由给定的需要生成字符串中字符个数 CharNum， 图片宽度 Width 和高度 Height 确定字号 FontSize，
//确保不因字号过大而不能全部显示在图片上
int fontWidth = (int)Math.Round(width / (charNum + 2) / 1.3);
int fontHeight = (int)Math.Round(height / 1.5);
//字号取二者中小者，以确保所有字符能够显示，并且字符的下半部分也能显示
fontSize = fontWidth <= fontHeight ? fontWidth : fontHeight;
//创建位图对象
bitMap = new Bitmap(width + fontSize, height);
//根据上面创建的位图对象创建绘图图面
gph = Graphics.FromImage(bitMap);
//设定验证码图片背景色
gph.Clear(GetControllableColor(200));
//产生随机干扰线条
for (int i = 0; i < 10; i++)
{
Pen backPen = new Pen(GetControllableColor(100), 2);
//线条起点
int x = random.Next(width);
int y = random.Next(height);
//线条终点
int x2 = random.Next(width);
int y2 = random.Next(height);
//划线
gph.DrawLine(backPen, x, y, x2, y2);
}
//定义一个含10种字体的数组
String[] fontFamily =
{
"Arial", "Verdana", "Comic Sans MS", "Impact", "Haettenschweiler",
"Lucida Sans Unicode", "Garamond", "Courier New", "Book Antiqua", "Arial Narrow"
};
SolidBrush sb = new SolidBrush(GetControllableColor(0));
//通过循环,绘制每个字符,
for (int i = 0; i < text.Length; i++)
{
Font textFont = new Font(fontFamily[random.Next(10)], fontSize, FontStyle.Bold); //字体随机,字号大小30,加粗
//每次循环绘制一个字符,设置字体格式,画笔颜色,字符相对画布的X坐标,字符相对画布的Y坐标
int space = (int)Math.Round((double)((width - fontSize * (charNum + 2)) / charNum));
//纵坐标
int y = (int)Math.Round((double)((height - fontSize) / 3));
gph.DrawString(text.Substring(i, 1), textFont, sb, fontSize + i * (fontSize + space), y);
}
//扭曲图片
bitMap = TwistImage(bitMap, true, random.Next(3, 5), random.Next(3));
bitMap.Save(memStream, ImageFormat.Gif);
bitMap.Dispose();
return memStream.ToArray();
}
/// <summary>
/// 产生一种 R,G,B 均大于 colorBase 随机颜色，以确保颜色不会过深
/// </summary>
/// <returns>背景色</returns>
private static Color GetControllableColor(int colorBase)
{
Color color = Color.Black;
Random random = new Random();
//确保 R,G,B 均大于 colorBase，这样才能保证背景色较浅
color = Color.FromArgb(random.Next(56) + colorBase, random.Next(56) + colorBase, random.Next(56) + colorBase);
return color;
}
/// <summary>
/// 扭曲图片
/// </summary>
/// <param name="srcBmp"></param>
/// <param name="bXDir"></param>
/// <param name="dMultValue"></param>
/// <param name="dPhase"></param>
/// <returns></returns>
private static Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase)
{
int leftMargin = 0;
int rightMargin = 0;
int topMargin = 0;
int bottomMargin = 0;
float PI2 = 6.28318530717959f;
Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height);
double dBaseAxisLen = bXDir ? Convert.ToDouble(destBmp.Height) : Convert.ToDouble(destBmp.Width);
for (int i = 0; i < destBmp.Width; i++)
{
for (int j = 0; j < destBmp.Height; j++)
{
double dx = 0;
dx = bXDir ? PI2 * Convert.ToDouble(j) / dBaseAxisLen : PI2 * Convert.ToDouble(i) / dBaseAxisLen;
dx += dPhase;
double dy = Math.Sin(dx);
//取得当前点的颜色
int nOldX = 0;
int nOldY = 0;
nOldX = bXDir ? i + Convert.ToInt32(dy * dMultValue) : i;
nOldY = bXDir ? j : j + Convert.ToInt32(dy * dMultValue);
var color = srcBmp.GetPixel(i, j);
if (nOldX >= leftMargin && nOldX < destBmp.Width - rightMargin && nOldY >= bottomMargin &&
nOldY < destBmp.Height - topMargin)
{
destBmp.SetPixel(nOldX, nOldY, color);
}
}
}
return destBmp;
}
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