asp.net之生成驗證碼的辦法集錦（一）。本站提示廣大學習愛好者：（asp.net之生成驗證碼的辦法集錦（一））文章只能為提供參考，不一定能成為您想要的結果。以下是asp.net之生成驗證碼的辦法集錦（一）正文
如今許多網站都有注冊登錄的頁面，為了更好的知足用戶體驗和網站的平安性，許多網站都采取靜態生成的圖形碼或許是附加碼停止驗證,上面把生成驗證碼的辦法給年夜家整頓以下.
完成驗證技巧就是在辦事器端生成一個隨機數，並將其保留在內存中，發送給閱讀器，並以圖片的情勢提交給用戶。之前在做項目進程中，完成了一個應用script停止用戶注冊及登錄的驗證碼時，發明有各類生成驗證碼的方法，上面重要是幾種分歧的生成驗證碼的方法：
1、繪制純數字的網站驗證碼
本實例完成的是數字驗證碼技巧，即隨機生成4位數字作為驗證碼。在開辟繪制會員登錄驗證模塊時可使用數字驗證碼技巧。
■設計進程
在一個新建的窗體CheckCode.aspx中編寫生成數字驗證碼的辦法：
private string RndNum()
{
int number;
char code;
string checkCode = String.Empty;
System.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();
}
Response.Cookies.Add(new HttpCookie("yzmcode", checkCode));
return checkCode;
}
private void CreateCheckCodeImage(string checkCode)
{
if (checkCode == null || checkCode.Trim() == String.Empty)
return;
System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 12.5)), 22);
Graphics g = Graphics.FromImage(image);
try
{
//生成隨機生成器
Random random = new Random();
//清空圖片配景色
g.Clear(Color.White);
//繪圖片的配景樂音線
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, y1, x2, y2);
}
Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));
System.Drawing.Drawing2D.LinearGradientBrush brush = new
System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height),
Color.Blue, Color.DarkRed, 1.2f, true);
g.DrawString(checkCode, font, brush, 2, 2);
//繪圖片的遠景樂音點
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()));
}
//繪圖片的邊框線
g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
System.IO.MemoryStream ms = new System.IO.MemoryStream();
image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
Response.ClearContent();
Response.ContentType = "image/Gif";
Response.BinaryWrite(ms.ToArray());
}
finally
{
g.Dispose();
image.Dispose();
}
}
然後在Page_Load中挪用CreateCheckCodeImage（）：
protected void Page_Load(object sender, EventArgs e)
{
this.CreateCheckCodeImage(RndNum());
}
那末在我們登錄的窗口中便可以經由過程簡略的控件：
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
<asp:ImageButton ID="ImageButton2" runat="server" ImageUrl="~/CheckCode.aspx" Width="50" Height="30"/><asp:Label
ID="Label1" runat="server" Text="看不清晰？點擊圖片換一個" Height="16px"
Font-Size="Small" ForeColor="Red"></asp:Label>
<br />
<asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Button" />
在Button1_Click中對驗證碼輸出的准確性停止斷定：
protected void Button1_Click(object sender, EventArgs e)
{
if (String.Compare(Request.Cookies["yzmcode"].Value, TextBox1.Text, true) != 0)
{
Response.Write("<script>alert('驗證碼毛病！')</script>");
}
else
Response.Write("<script>alert('驗證碼准確！')</script>");
}
2、繪制數字與字母組合的網站驗證碼
和純數字的很類似，詳細差別在隨機生成字符串的辦法中
private string GenerateCheckCode()
{
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();
}
Response.Cookies.Add(new HttpCookie("CheckCode", checkCode));
return checkCode;
}
字符串生成後，接上去就是將該字符串繪制成圖片顯示出來。代碼以下：
private void CreateCheckCodeImage(string checkCode)
{
if (checkCode == null || checkCode.Trim() == String.Empty)
return;
System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 12.5)), 22); Graphics g = Graphics.FromImage(image);
try
{
//生成隨機生成器
Random random = new Random();
//清空圖片配景色
g.Clear(Color.White);
//繪圖片的配景樂音線
for (int i = 0; i < 2; 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", 12, (System.Drawing.FontStyle.Bold));
System.Drawing.Drawing2D.LinearGradientBrush brush = new
System.Drawing.Drawing2D.LinearGradientBrush(
new Rectangle(0, 0, image.Width, image.Height),
Color.Blue, Color.DarkRed, 1.2f, true);
g.DrawString(checkCode, font, brush, 2, 2);
//繪圖片的遠景樂音點
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()));
}
//繪圖片的邊框線
g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
System.IO.MemoryStream ms = new System.IO.MemoryStream();
image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
Response.ClearContent();
Response.ContentType = "image/Gif";
Response.BinaryWrite(ms.ToArray());
}
finally
{
g.Dispose();
image.Dispose();
}
}
在登錄的窗口停止驗證碼輸出能否准確的斷定：
protected void Button1_Click(object sender, EventArgs e)
{
HttpCookie cookie = Request.Cookies["CheckCode"];
if (cookie.Value == this.TextBox1.Text.Trim())
{
Response.Write("<script>alert('驗證碼准確！')</script>");
}
else
{
Response.Write("<script>alert('驗證碼毛病！')</script>");
}
}
那末有關於數字與字母組合的網站驗證碼就生成了。
3、四則運算式的驗證碼
其他的和數字和字母混雜生成的驗證碼類似，我就不寫了，詳細差別在隨機生成四則運算式的辦法中，以下：
private string GenerateCheckCode()
{
Random rd = new Random();
int Results = 0;
int Num1 = rd.Next(10);
int Num2 = rd.Next(10);
string Expressions = "";
int F = (rd.Next(4) + 1);
switch (F)
{
case 1:
Results = Num1 + Num2;
Expressions = Num1 + "+" + Num2;
break;
case 2:
Results = Num1 - Num2;
Expressions = Num1 + "-" + Num2;
break;
case 3:
Results = Num1 * Num2;
Expressions = Num1 + "*" + Num2;
break;
case 4:
if (Num2 > 0)
{
Results = Convert.ToInt16(Num1 / Num2);
Expressions = Num1 + "/" + Num2;
}
else
{
Results = Num1;
Expressions = Num1 + "/1";
}
break;
}
Session["Code"] = Results.ToString();
return Expressions;
}
此篇文章重要引見了三種辦法生成驗證碼，願望年夜家愛好。
