现有如下三个页面1.aspx 2.aspx 3.aspx1.aspx 以get方式传递变量a=123给2.aspx,在2.aspx中可以获得Request.QueryString["a"]
2.aspx中 以用了3.aspx <img alt="" src="3.aspx" />问题:当点击1.aspx的链接时候,3.aspx如何获得变量a?
2.aspx中 以用了3.aspx <img alt="" src="3.aspx" />问题:当点击1.aspx的链接时候,3.aspx如何获得变量a?
<img alt="" src="3.aspx" />
这两个什么意思?
2.aspx前台:
<img alt="" src="3.aspx?a=<%=a%>" /> 后台:
protected string a="";
a = Request.QueryString["a"];
我试了 <img alt="" src="3.aspx?a= <%=a%>" /> 这样变量传不到 3.aspx页啊简单一点:就是说3.aspx通过变量a生成图片格式,3.aspx怎样得到传来的便利?
{
Response.Redirect("2.aspx?a=4");
}
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2.aspx<img alt="" src="3.aspx?a=<%=a%>" /> 2.aspx.cs protected string a = "";
protected void Page_Load(object sender, EventArgs e)
{
a = Request.QueryString["a"];
}
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3.aspx.csusing System.Drawing.Imaging;
using System.IO;
using System.Drawing;
//引用上面3个命名空间 protected void Page_Load(object sender, EventArgs e)
{
int aa = 0;
if(string.IsNullOrEmpty(Request["a"]))
aa = 4;
else
aa = int.Parse(Request.QueryString["a"]); string tmp = RndNum(aa);
HttpCookie a = new HttpCookie("ImageV", tmp);
Response.Cookies.Add(a);
this.ValidateCode(tmp);
}
private void ValidateCode(string VNum)
{
Bitmap Img = null;
Graphics g = null;
MemoryStream ms = null; int gheight = VNum.Length * 12;
Img = new Bitmap(gheight, 25);
g = Graphics.FromImage(Img);
//背景颜色
g.Clear(Color.White);
//文字字体
Font f = new Font("Arial Black", 10);
//文字颜色
SolidBrush s = new SolidBrush(Color.Black);
g.DrawString(VNum, f, s, 3, 3);
ms = new MemoryStream();
Img.Save(ms, ImageFormat.Jpeg);
Response.ClearContent();
Response.ContentType = "image/Jpeg";
Response.BinaryWrite(ms.ToArray()); g.Dispose();
Img.Dispose();
Response.End();
} private string RndNum(int VcodeNum)
{
string Vchar = "0,1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p" +
",q,r,s,t,u,v,w,x,y,z";
string[] VcArray = Vchar.Split(new Char[] { ',' });
string VNum = "";
int temp = -1; Random rand = new Random(); for (int i = 1; i < VcodeNum + 1; i++)
{
if (temp != -1)
{
rand = new Random(i * temp * unchecked((int)DateTime.Now.Ticks));
} int t = rand.Next(35);
if (temp != -1 && temp == t)
{
return RndNum(VcodeNum);
}
temp = t;
VNum += VcArray[t];
}
return VNum;
}
我一直在3.aspx里 检查变量输出//Response.Write(a);去掉这一句就好了 图片就显示出来 but why?
<img>变成服务器控件:
<img id='img1' runat='server'>C# code:img1.Src="3.aspx";
if (!string.IsNullOrEmpty(Request.QueryString["a"]))
{
img1.Src="3.aspx?a=" + Request.QueryString["a"].ToString();
}3.aspx对Request.QueryString["a"]内部处理