在MVC中進行留言，評論等功能時，不可避免會用到表單提交時的驗證碼問題，有時，我們的作法是，當表單被提交後，在controller裡去判斷驗證碼的正確與否，但我認為這種使用者體驗是很差的，今天正好有後時間，把這方法的東西總結一下：
首先，在公用專案中建立一個生成圖片驗證碼的型別ValidateCode，程式碼如下：
/// <summary>
/// 生成驗證碼物件
/// </summary>
public class ValidateCode
{
public ValidateCode()
{
}
///<summary>
/// 驗證碼的最大長度
///</summary>
public int MaxLength
{
get { return 10; }
}
///<summary>
/// 驗證碼的最小長度
///</summary>
public int MinLength
{
get { return 1; }
}
///<summary>
/// 生成驗證碼
///</summary>
///<param name="length">指定驗證碼的長度</param>
///<returns></returns>
public string CreateValidateCode(int length)
{
int[] randMembers = new int[length];
int[] validateNums = new int[length];
string validateNumberStr = "";
//生成起始序列值
int seekSeek = unchecked((int)DateTime.Now.Ticks);
Random seekRand = new Random(seekSeek);
int beginSeek = (int)seekRand.Next(0, Int32.MaxValue - length * 10000);
int[] seeks = new int[length];
for (int i = 0; i < length; i++)
{
beginSeek += 10000;
seeks[i] = beginSeek;
}
//生成隨機數字
for (int i = 0; i < length; i++)
{
Random rand = new Random(seeks[i]);
int pownum = 1 * (int)Math.Pow(10, length);
randMembers[i] = rand.Next(pownum, Int32.MaxValue);
}
//抽取隨機數字
for (int i = 0; i < length; i++)
{
string numStr = randMembers[i].ToString();
int numLength = numStr.Length;
Random rand = new Random();
int numPosition = rand.Next(0, numLength - 1);
validateNums[i] = Int32.Parse(numStr.Substring(numPosition, 1));
}
//生成驗證碼
for (int i = 0; i < length; i++)
{
validateNumberStr += validateNums[i].ToString();
}
return validateNumberStr;
}
///<summary>
/// 建立驗證碼的圖片
///</summary>
///<param name="containsPage">要輸出到的page物件</param>
///<param name="validateNum">驗證碼</param>
public byte[] CreateValidateGraphic(string validateCode)
{
Bitmap image = new Bitmap((int)Math.Ceiling(validateCode.Length * 14.0), 22);
Graphics g = Graphics.FromImage(image);
try
{
//生成隨機生成器
Random random = new Random();
//清空圖片背景色
g.Clear(Color.White);
//畫圖片的干擾線
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 Font("Arial", 14, (FontStyle.Bold | FontStyle.Italic));
LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height),
Color.Blue, Color.DarkRed, 1.5f, true);
g.DrawString(validateCode, font, brush, 3, 2);
//畫圖片的前景干擾點
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()));
}
//畫圖片的邊框線
g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
//儲存圖片資料
MemoryStream stream = new MemoryStream();
image.Save(stream, ImageFormat.Jpeg);
//輸出圖片流
return stream.ToArray();
}
finally
{
g.Dispose();
image.Dispose();
}
}
}
/// 生成驗證碼物件
/// </summary>
public class ValidateCode
{
public ValidateCode()
{
}
///<summary>
/// 驗證碼的最大長度
///</summary>
public int MaxLength
{
get { return 10; }
}
///<summary>
/// 驗證碼的最小長度
///</summary>
public int MinLength
{
get { return 1; }
}
///<summary>
/// 生成驗證碼
///</summary>
///<param name="length">指定驗證碼的長度</param>
///<returns></returns>
public string CreateValidateCode(int length)
{
int[] randMembers = new int[length];
int[] validateNums = new int[length];
string validateNumberStr = "";
//生成起始序列值
int seekSeek = unchecked((int)DateTime.Now.Ticks);
Random seekRand = new Random(seekSeek);
int beginSeek = (int)seekRand.Next(0, Int32.MaxValue - length * 10000);
int[] seeks = new int[length];
for (int i = 0; i < length; i++)
{
beginSeek += 10000;
seeks[i] = beginSeek;
}
//生成隨機數字
for (int i = 0; i < length; i++)
{
Random rand = new Random(seeks[i]);
int pownum = 1 * (int)Math.Pow(10, length);
randMembers[i] = rand.Next(pownum, Int32.MaxValue);
}
//抽取隨機數字
for (int i = 0; i < length; i++)
{
string numStr = randMembers[i].ToString();
int numLength = numStr.Length;
Random rand = new Random();
int numPosition = rand.Next(0, numLength - 1);
validateNums[i] = Int32.Parse(numStr.Substring(numPosition, 1));
}
//生成驗證碼
for (int i = 0; i < length; i++)
{
validateNumberStr += validateNums[i].ToString();
}
return validateNumberStr;
}
///<summary>
/// 建立驗證碼的圖片
///</summary>
///<param name="containsPage">要輸出到的page物件</param>
///<param name="validateNum">驗證碼</param>
public byte[] CreateValidateGraphic(string validateCode)
{
Bitmap image = new Bitmap((int)Math.Ceiling(validateCode.Length * 14.0), 22);
Graphics g = Graphics.FromImage(image);
try
{
//生成隨機生成器
Random random = new Random();
//清空圖片背景色
g.Clear(Color.White);
//畫圖片的干擾線
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 Font("Arial", 14, (FontStyle.Bold | FontStyle.Italic));
LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height),
Color.Blue, Color.DarkRed, 1.5f, true);
g.DrawString(validateCode, font, brush, 3, 2);
//畫圖片的前景干擾點
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()));
}
//畫圖片的邊框線
g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
//儲存圖片資料
MemoryStream stream = new MemoryStream();
image.Save(stream, ImageFormat.Jpeg);
//輸出圖片流
return stream.ToArray();
}
finally
{
g.Dispose();
image.Dispose();
}
}
}
然後，在當前公用的controller中新增一個返回檔案型別的action,當然也可以是所有返回型別的基類ActionResult，這個方法用來返回一個影象物件：
/// <summary>
/// 生成驗證碼影象物件
/// </summary>
/// <returns></returns>
public ActionResult GetValidateCode()
{
ValidateCode vCode = new ValidateCode();
string code = vCode.CreateValidateCode(4);
Session["ValidateCode"] = code;
byte[] bytes = vCode.CreateValidateGraphic(code);
return File(bytes, @"image/jpeg");
}
/// 生成驗證碼影象物件
/// </summary>
/// <returns></returns>
public ActionResult GetValidateCode()
{
ValidateCode vCode = new ValidateCode();
string code = vCode.CreateValidateCode(4);
Session["ValidateCode"] = code;
byte[] bytes = vCode.CreateValidateGraphic(code);
return File(bytes, @"image/jpeg");
}
再次，需要我們寫一個返回當前驗證嗎的方法，這是作無重新整理驗證碼的關鍵：
/// <summary>
/// 得到當前驗證碼
/// </summary>
/// <returns></returns>
public ActionResult GetCurrentValidateCode()
{
return Content(Session["ValidateCode"].ToString());
}
/// 得到當前驗證碼
/// </summary>
/// <returns></returns>
public ActionResult GetCurrentValidateCode()
{
return Content(Session["ValidateCode"].ToString());
}
最後，就是頁面上的事了，看程式碼：
<div id="ValidateCodeSpan">
請輸入驗證碼：@Html.TextBox("VCode")
<img id="valiCode" style="cursor: pointer;" src="/Common/GetValidateCode" alt="看不清？請點我" />
@Html.Hidden("ValidateCode")
<script type="text/javascript">
$(function () {
//首次載入
$("#valiCode").attr("src","/Common/GetValidateCode?time=" + (new Date()).getTime());
$.get("/Common/GetCurrentValidateCode", function (data) {
$("#ValidateCode").val(data);
});
//單擊驗證碼事件
$("#valiCode").bind("click", function () {
this.src = "/Common/GetValidateCode?time=" + (new Date()).getTime();
$.get("/Common/GetCurrentValidateCode", function (data) {
$("#ValidateCode").val(data);
});
});
});
</script>
</div>
請輸入驗證碼：@Html.TextBox("VCode")
<img id="valiCode" style="cursor: pointer;" src="/Common/GetValidateCode" alt="看不清？請點我" />
@Html.Hidden("ValidateCode")
<script type="text/javascript">
$(function () {
//首次載入
$("#valiCode").attr("src","/Common/GetValidateCode?time=" + (new Date()).getTime());
$.get("/Common/GetCurrentValidateCode", function (data) {
$("#ValidateCode").val(data);
});
//單擊驗證碼事件
$("#valiCode").bind("click", function () {
this.src = "/Common/GetValidateCode?time=" + (new Date()).getTime();
$.get("/Common/GetCurrentValidateCode", function (data) {
$("#ValidateCode").val(data);
});
});
});
</script>
</div>