c# 返回图片

关注:206 答案:2 手机版

解决时间 2021-01-17 02:09

提问者网友：妳螚鬧俄螚笑
2021-01-16 03:05

返回字符串
public static string str()
{
return "Hello";
}
比如说上面的可以返回Hello字符串吗？如果我想返回一个照片的话怎么弄！

比如说：这个代码怎么写
public static Image imge()
{
我这里通过代码形成了一个照片img1;
retun img1;
}

类此的功能怎么实现！

最佳答案

二级知识专家网友：没仙气的仙女
2021-01-16 04:15

/// <summary>
/// 验证码生成类
/// </summary>
public class verify_code : IHttpHandler, IRequiresSessionState
{

public void ProcessRequest(HttpContext context)
{
int codeW = 80;
int codeH = 22;
int fontSize = 16;
string chkCode = string.Empty;
//颜色列表，用于验证码、噪线、噪点
Color[] color = { Color.Black, Color.Red, Color.Blue, Color.Green, Color.Orange, Color.Brown, Color.Brown, Color.DarkBlue };
//字体列表，用于验证码
string[] font = { "Times New Roman", "Verdana", "Arial", "Gungsuh", "Impact" };
//验证码的字符集，去掉了一些容易混淆的字符
char[] character = { '2', '3', '4', '5', '6', '8', '9', 'a', 'b', 'd', 'e', 'f', 'h', 'k', 'm', 'n', 'r', 'x', 'y', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'R', 'S', 'T', 'W', 'X', 'Y' };
Random rnd = new Random();
//生成验证码字符串
for (int i = 0; i < 4; i++)
{
chkCode += character[rnd.Next(character.Length)];
}
//写入Session
context.Session[DTKeys.SESSION_CODE] = chkCode;
//创建画布
Bitmap bmp = new Bitmap(codeW, codeH);
Graphics g = Graphics.FromImage(bmp);
g.Clear(Color.White);
//画噪线
for (int i = 0; i < 1; i++)
{
int x1 = rnd.Next(codeW);
int y1 = rnd.Next(codeH);
int x2 = rnd.Next(codeW);
int y2 = rnd.Next(codeH);
Color clr = color[rnd.Next(color.Length)];
g.DrawLine(new Pen(clr), x1, y1, x2, y2);
}
//画验证码字符串
for (int i = 0; i < chkCode.Length; i++)
{
string fnt = font[rnd.Next(font.Length)];
Font ft = new Font(fnt, fontSize);
Color clr = color[rnd.Next(color.Length)];
g.DrawString(chkCode[i].ToString(), ft, new SolidBrush(clr), (float)i * 18 + 2, (float)0);
}
//画噪点
for (int i = 0; i < 100; i++)
{
int x = rnd.Next(bmp.Width);
int y = rnd.Next(bmp.Height);
Color clr = color[rnd.Next(color.Length)];
bmp.SetPixel(x, y, clr);
}
//清除该页输出缓存，设置该页无缓存
context.Response.Buffer = true;
context.Response.ExpiresAbsolute = System.DateTime.Now.AddMilliseconds(0);
context.Response.Expires = 0;
context.Response.CacheControl = "no-cache";
context.Response.AppendHeader("Pragma", "No-Cache");
//将验证码图片写入内存流，并将其以 "image/Png" 格式输出
MemoryStream ms = new MemoryStream();
try
{
bmp.Save(ms, ImageFormat.Png);
context.Response.ClearContent();
context.Response.ContentType = "image/Png";
context.Response.BinaryWrite(ms.ToArray());
}
finally
{
//显式释放资源
bmp.Dispose();
g.Dispose();
}
}

public bool IsReusable
{
get
{
return false;
}
}

全部回答

1楼网友：等待、埖开
2021-01-16 04:23

/// <summary> /// 验证码生成类 /// </summary> public class verify_code : ihttphandler, irequiressessionstate { public void processrequest(httpcontext context) { int codew = 80; int codeh = 22; int fontsize = 16; string chkcode = string.empty; //颜色列表，用于验证码、噪线、噪点 color[] color = { color.black, color.red, color.blue, color.green, color.orange, color.brown, color.brown, color.darkblue }; //字体列表，用于验证码 string[] font = { "times new roman", "verdana", "arial", "gungsuh", "impact" }; //验证码的字符集，去掉了一些容易混淆的字符 char[] character = { '2', '3', '4', '5', '6', '8', '9', 'a', 'b', 'd', 'e', 'f', 'h', 'k', 'm', 'n', 'r', 'x', 'y', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'j', 'k', 'l', 'm', 'n', 'p', 'r', 's', 't', 'w', 'x', 'y' }; random rnd = new random(); //生成验证码字符串 for (int i = 0; i < 4; i++) { chkcode += character[rnd.next(character.length)]; } //写入session context.session[dtkeys.session_code] = chkcode; //创建画布 bitmap bmp = new bitmap(codew, codeh); graphics g = graphics.fromimage(bmp); g.clear(color.white); //画噪线 for (int i = 0; i < 1; i++) { int x1 = rnd.next(codew); int y1 = rnd.next(codeh); int x2 = rnd.next(codew); int y2 = rnd.next(codeh); color clr = color[rnd.next(color.length)]; g.drawline(new pen(clr), x1, y1, x2, y2); } //画验证码字符串 for (int i = 0; i < chkcode.length; i++) { string fnt = font[rnd.next(font.length)]; font ft = new font(fnt, fontsize); color clr = color[rnd.next(color.length)]; g.drawstring(chkcode[i].tostring(), ft, new solidbrush(clr), (float)i * 18 + 2, (float)0); } //画噪点 for (int i = 0; i < 100; i++) { int x = rnd.next(bmp.width); int y = rnd.next(bmp.height); color clr = color[rnd.next(color.length)]; bmp.setpixel(x, y, clr); } //清除该页输出缓存，设置该页无缓存 context.response.buffer = true; context.response.expiresabsolute = system.datetime.now.addmilliseconds(0); context.response.expires = 0; context.response.cachecontrol = "no-cache"; context.response.appendheader("pragma", "no-cache"); //将验证码图片写入内存流，并将其以 "image/png" 格式输出 memorystream ms = new memorystream(); try { bmp.save(ms, imageformat.png); context.response.clearcontent(); context.response.contenttype = "image/png"; context.response.binarywrite(ms.toarray()); } finally { //显式释放资源 bmp.dispose(); g.dispose(); } } public bool isreusable { get { return false; } }

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