Help with generic handlers

Question

User108409295 posted

I've made robot script of addition two numbers. My user should addition these two numbers for confirmation. i added generic handler ASHX file to my web address with folloving code:

Public Class Robot : Implements IHttpHandler
   
    Public Sub ProcessRequest(ByVal context As HttpContext) Implements IHttpHandler.ProcessRequest
        Dim rnd1 As New Random
        Dim rnd2 As New Random
        Dim i As Integer = rnd1.Next(1, 5)
        Dim j As Integer = rnd2.Next(5, 10)
        Dim prikaz As String = i & "+" & j & "= ?"
        Dim Rezultat As Integer = i + j
       
        Dim font As New Font("Tahoma", 25, FontStyle.Bold, GraphicsUnit.Pixel)
        Dim bitmapa As New Bitmap(100, 30)
        Dim grafika As Graphics = Graphics.FromImage(bitmapa)
        Dim podrucje As New Rectangle(0, 0, 100, 30)
        grafika.FillRectangle(Brushes.Red, podrucje)
        grafika.DrawRectangle(Pens.Black, podrucje)
        grafika.DrawString(prikaz, font, Brushes.Green, 0, 0)

        context.Response.ContentType = "Image/jpeg"
        bitmapa.Save(context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg)
       
        bitmapa.Dispose()
        grafika.Dispose()
    End Sub
 
    Public ReadOnly Property IsReusable() As Boolean Implements IHttpHandler.IsReusable
        Get
            Return False
        End Get
    End Property

End Class

In my .aspx file i have next code on button click:

imgSlika.ImageUrl = "~/Robot.ashx"

I want pass variable with name Razultat from ashx with picture to asp.page. So that i could compare result with value od textBox.

Please help.

Answer 1

User108409295 posted

I reorganized my question.

Answer 2

User-627724879 posted

 i think you are trying to do CAPTCHA:

http://www.codeproject.com/KB/custom-controls/CaptchaControl.aspx

http://www.codeplex.com/Captcha

Answer 3

User108409295 posted

Addition, but i want my own. I have a picture from handler, but i want addition two generated numbers in generic hanler and return result in aspx page so that i can compare result with user input.

Answer 4

User-1363023537 posted

Hi,

but i want my own.

you can create your own
 
simple CAPTCHA techniqe http://www.revenmerchantservices.com/page/C-Simple-Captcha.aspx 

like this, I have explained.

Satalaj

Answer 5

User108409295 posted

I've respolved everthing, this is my own captcha wit addition numbers and confirmation.

Thx to all

ASPX

<form id="form1" runat="server">
    <div>
        <asp:TextBox ID="txtCap" runat="server"></asp:TextBox>
        <br />
        <br />
        <asp:Button ID="btnProvjeri" runat="server" Text="Provjeri" />
        <asp:Label ID="Label1" runat="server"></asp:Label>
        <br />
        <br />
        <asp:Image ID="Image1" runat="server" ImageUrl="~/Robot.ashx" />
    </div>
 </form>

BUTTON CHECK

Protected Sub btnProvjeri_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnProvjeri.Click
        Dim odgovor As Integer = Convert.ToInt32(Context.Session("Rezultat"))

        If odgovor = Convert.ToInt32(txtCap.Text) Then
            Label1.Text = "OK"
        Else
            Label1.Text = "NO"
        End If

End Sub

GENERIC HANDLER

<%@ WebHandler Language="VB" %>

Imports System
Imports System.Web
Imports System.Drawing
Imports System.Web.SessionState

Public Class Robot : Implements IHttpHandler, IRequiresSessionState
    
    
    Public Sub ProcessRequest(ByVal context As HttpContext) Implements IHttpHandler.ProcessRequest
        Dim rnd1 As New Random
        Dim rnd2 As New Random
        Dim i As Integer = rnd1.Next(1, 5)
        Dim j As Integer = rnd2.Next(5, 10)
        Dim prikaz As String = i & "+" & j & "= ?"
        Dim Rezultat As Integer = i + j

        context.Session("Rezultat") = Rezultat

        Dim font As New Font("Tahoma", 25, FontStyle.Bold, GraphicsUnit.Pixel)
        Dim bitmapa As New Bitmap(100, 30)
        Dim grafika As Graphics = Graphics.FromImage(bitmapa)
        Dim podrucje As New Rectangle(0, 0, 100, 30)
        grafika.FillRectangle(Brushes.Red, podrucje)
        grafika.DrawRectangle(Pens.Black, podrucje)
        grafika.DrawString(prikaz, font, Brushes.Green, 0, 0)

        context.Response.ContentType = "Image/jpeg"
        bitmapa.Save(context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg)

        bitmapa.Dispose()
        grafika.Dispose()
    End Sub
 
    Public ReadOnly Property IsReusable() As Boolean Implements IHttpHandler.IsReusable
        Get
            Return False
        End Get
    End Property

End Class

Answer 6

User-1363023537 posted

Yes, when we are working with HttpHandler and Session variables
we need that handler to inherit IRequiresSessionState.