1.使用一个PictureBox空间，使用一个按钮，以刷新验证码。
2.首先定义CheckCode()方法，以生成4为英文及数字组成的字符串序列：
private string CheckCode()
{
int number;
char code;
string checkCode = String.Empty;
Random random = new Random();
for (int i = 0; i < 4; i++)
{
number=random.Next();
if(number%2==0)
code=(char)('0'+(char)(number%10));
else
code=(char)('A'+(char)(number%26));
checkCode += " " + code.ToString();
}
return checkCode;
}
3.自定义CodeImage()方法，将CheckCode()方法生成的序列转化为图片并显示：
private void CodeImage(string checkCode)
{
if (checkCode == null || checkCode.Trim() == String.Empty)
{
return;
}
System.Drawing.Bitmap image=new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length*50.0)),50);
Graphics g=Graphics.FromImage(image);
try
{
Random random = new Random();
g.Clear(Color.White);
for (int i = 0; i < 3; 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.Black), x1, y1, x2, y2);
}
Font font = new System.Drawing.Font("Arial", 30, (System.Drawing.FontStyle.Bold));
g.DrawString(checkCode, font, new SolidBrush(Color.Red), 2, 2);
for (int i = 0; i < 200; 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);
this.pictureBox1.Width = image.Width;
this.pictureBox1.Height = image.Height;
this.pictureBox1.BackgroundImage = image;
}
catch
{
}
}
4.
private void Form1_Load(object sender, EventArgs e)
{
CodeImage(CheckCode());
}
private void button1_Click(object sender, EventArgs e)
{
CodeImage(CheckCode());
}