Using VB2008 to acccess the Betfair API: A tutorial

[Mumbles0]

Graphics (continued)

BigSprout,

I think you are getting a bit confused by the graphics.
Let’s look at some fundamentals...

This code draws a rectangle on a form:

Private Sub bDraw_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles bDraw.Click

  Dim Graph As Graphics = Me.CreateGraphics   'The graphics object
  Graph.DrawRectangle(Pens.Blue, 20, 10, 200, 300)  'Draw the rectangle

End Sub

Here Graph is a System.Drawing.Graphics object which incorporates all of the drawing methods we require. I like to think of this object as representing the drawing surface of the current form. We draw the desired rectangle using the DrawRectangle method.

There you have it. But ......

The drawing is very fragile. If you put something in front of it on the desktop, it will erase.

To overcome this problem, graphics are typically drawn from within a form’s Paint event. This event fires whenever the form is required to be redrawn. If you put a Beep() statement in the Paint event handler and rearrange your Desktop a bit you will see what I mean.

So alternatively we can draw the rectangle from within the Paint event like this:

Private Sub Form1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles Me.Paint

  e.Graphics.DrawRectangle(Pens.Blue, 20, 10, 200, 300)  'Draw the rectangle

End Sub

Now the rectangle persists. It is redrawn by the Paint event whenever the system deems that repainting is required. Note that here we do not have to create a Graphics object. One is given to us in the e.Graphics parameter.

So that’s what the Paint event is for. Personally I find this quite dumb, but there is a better way using buffered graphics. We might have a look at this in a future step.

[BigSprout]

Sports,
checking out how the treeview has been used in the tutorial, I assume you have done the same and you are using:

   Private Sub TreeView1_AfterSelect(ByVal sender As System.Object, ByVal e As System.Windows.Forms.TreeViewEventArgs) Handles TreeView1.AfterSelect

	My code is here

    End Sub

if that is the case then every time you click on a node it will fire, double click causing double readings, the computer(Treeview) is doing what you are telling it to do.

What you need to do is investigate using:

   Private Sub TreeView1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles TreeView1.Click

	Code for single click events

    End Sub



    Private Sub TreeView1_DoubleClick(ByVal sender As Object, ByVal e As System.EventArgs) Handles TreeView1.DoubleClick

 	Code for double click events

   End Sub

One problem is that the Treeview_click/doubleclick do not have the parameter "ByVal e As System.Windows.Forms.TreeViewEventArgs" and so you will not be able to use "e.node" without declaring "....TreeviewEventArgs"

I didn't need a treeview, so did not investigate further on its workings, but when I have a problem I click on "Help" in the VS2010 and use a few key words for a search.

Here is something that come up on "Treeview doubleclick" search:
http://social.msdn.microsoft.com/for...2-5543A60467A3


cheers Les

[Sports API + VB .Net]

Thanks for your reply bro. but the treeview is not working for me i am using service buk.getallmarkets and it displays main events correctly Cricket , Snooker , Horse Racing but when i double click on Cricket event it shows child markets in groups like Group C then other perticular market and sometime it double the same event and sometime more then 2 times double .. the treeview i want is as same as on betfair website how is it possible please help me out

[BigSprout]

Thanks for that Mumbles, your way is going to be much neater than how I resolved the problem (temporarily), I added this on Form2:

   [COLOR="Gray"]Sub wb_AddRectangle([COLOR="Black"]ByVal e As System.Windows.Forms.PaintEventArgs[/COLOR], ByVal Lt As Integer, ByVal Tp As Integer, ByVal Wd As Integer, ByVal Ht As Integer)

        ...the code...

    End Sub[/COLOR]

on the main Form did this:

    [COLOR="Gray"]Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        [COLOR="Black"]Dim f As System.Windows.Forms.PaintEventArgs[/COLOR]
        FmWebPage.Show()
        FmWebPage.Left = Me.Left + Me.Width
        FmWebPage.WindowState = FormWindowState.Maximized
        FmWebPage.wb_AddRectangle([COLOR="Black"]f[/COLOR], 20, 20, 500, 400)

    End Sub[/COLOR]

I got this warning, but the the rectangle displayed on FmWebPage okay:

Warning 1 Variable 'f' is used before it has been assigned a value. A null reference exception could result at runtime...

Away this weekend, so will have another play next week and report - this is a steep learning curve for me from Delphi-6 (which was outdated by the new millennia)

cheers Les



Edited:
Just re-read your post:

As you've got it, the sub will only draw a rectangle on Me - being the form on which the sub is located...

the sub "AddRectangle" was on Form2 but would not display the rectangle on Form2 until I added "ByVal e As System.Windows.Forms.PaintEventArgs" as a parameter, this then added the "f" warning.
Note. deleted using the "Paint" Sub method as it continually fired (which I didn't want happening

[Mumbles0]

BigSprout,

Graphics is indeed an interesting topic.

As you've got it, the sub will only draw a rectangle on Me - being the form on which the sub is located. If you want to draw a rectangle on another form then add an extra parameter to specify the target form:

[COLOR="Gray"]Sub AddRectangle([COLOR="Black"]ByVal TheForm As Form,[/COLOR] ByVal Lt As Integer, ByVal Tp As Integer, ByVal Wd As Integer, ByVal Ht As Integer)
    'Add rectangles to the Web Page Form for the Price/Volume charts

    Dim myBrush As New System.Drawing.SolidBrush(System.Drawing.Color.Red)
    Dim myPen As New System.Drawing.Pen(System.Drawing.Color.Black)
    Dim formGraphics As System.Drawing.Graphics

    formGraphics = [COLOR="Black"]TheForm[/COLOR].CreateGraphics()
    formGraphics.DrawRectangle(myPen, New Rectangle(Lt, Tp, Wd, Ht))
    formGraphics.FillRectangle(myBrush, New Rectangle(Lt, Tp, Wd, Ht))
    myPen.Dispose()
    myBrush.Dispose()
    formGraphics.Dispose()

  End Sub[/COLOR]

You can then call it from any form like this:

AddRectangle(Me, 20, 10, 200, 300)

or perhaps:

AddRectangle(Form2, 20, 10, 200, 300)

[BigSprout]

Persevered and came up with a solution:

   Private Sub Form2_Paint(ByVal sender As System.Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles MyBase.Paint
        AddRectangle(20, 10, 200, 300)
    End Sub

...now to get it all working


cheers Les

[BigSprout]

Graphics drawing

In keeping with this tutorial I have tried to extend it to include graphics and have come across a problem that I am unable to solve.

I have dual monitors, on one monitor I have Form1 which displays the markets, fields, Betting Panel etc,
on the 2nd monitor I have Form2 with 8 WebBrowsers showing the price/volume charts of selected runners.

a. it is slow in filling all web browsers
b. the charts are already delayed, so are of minimal use

My next stage in the project is to collect the data and display it graphically on Form2

I found this code and it works on Form1, but I can't seem to get it to work on form2 (only see a blank form2)

   Sub AddRectangle(ByVal Lt As Integer, ByVal Tp As Integer, ByVal Wd As Integer, ByVal Ht As Integer)
        'Add rectangles to the Web Page Form for the Price/Volume charts

        
        Dim myBrush As New System.Drawing.SolidBrush(System.Drawing.Color.Red)
        Dim myPen As New System.Drawing.Pen(System.Drawing.Color.Black)
        Dim formGraphics As System.Drawing.Graphics

        formGraphics = Me.CreateGraphics()
        formgraphics.DrawRectangle(myPen, New Rectangle(Lt, Tp, Wd, Ht))
        formgraphics.FillRectangle(myBrush, New Rectangle(Lt, Tp, Wd, Ht))
        myPen.Dispose()
        myBrush.Dispose()
        formGraphics.Dispose()

    End Sub

I have tried sending to form2 from Form1 and also activating the code on form2 to no success.

I can write the code to display several rectangles and show the nice squiggly lines representing change in last matched prices once I can work out how to display graphics on a separate form.

I would appreciate some help with this minor problem.

cheers Les

[BigSprout]

Hi Sports,
I am only interested in Aus horse racing and I have designed my API program with this in mind, I also enjoy betting and don't see the point in designing a bot to do all the enjoyable stuff for me.

That said, to have the treeview populated on Form_Load, there is a major step that is needed to be carried out beforehand:

"Login successfully"

This requires your "Username" and "Password" stored either in a file or in "My.Settings" - storing this type of data is NOT RECOMMENDED, so populating a treeview in Form_Load is something I am not even going to attempt to explain.

You could however, have your Login sub call the "Sub Call_PopulateTreview()" when the Login is successful

When reading the tutorials, where you see:
Print(.bestPricesToBack(0).price)

replace with:
dgvField("FdBk", .sortOrder).Value =.bestPricesToBack(0).price

where dgvField is the name of a "DataGridView",
and "FdBk" is the name of the column header

a "for..next" loop could be used to read all 3 back/lay prices into different dgvField columns

This post by Mumbles explains loading runners, just use the above code to display the odds:
https://forum.bdp.betfair.com/showpo...&postcount=475

hope this is of some use
cheers Les

[Sports API + VB .Net]

hi bigsproute....
brother i am reading this thread for last six months but i didnt get the idea that how can i make a bot which is look like betfair website like on form_load i populate treeview (provide by mumble) then display runners and three back and lay in grid and bet on appropreiate selection i am very confused if i didnt complete this task may be i fail in my life please if you can train me and send me some sort of help i will be very thankfull of yours

[Sports API + VB .Net]

Hi Mumble thanks for this great tuitorial can you point out me the page in which you have disscussed about how to display odds in grid (anygrid).......
what i am trying to do is on form load i populate treeview then get market id then how to display runners and odds in grid to bet please reply me as sooon as possbile with full detail i will be very thank full of yours bye tc have a nice day

[Timmyag]

thank you
missed that, your guide was a big help

[Mumbles0]

Timmyag,

Looks like you've added a Service Reference instead of a Web Reference. This is a common trap. See this post.

[Timmyag]

Logging in

Ok i got stuck at step 1, i've fixed it now, well maybe but either i'm doing something daft or the guide needs updating

i' tried to follow the guide and got

Public Class testform
    Dim oHeaderGL As New BFGlobal.APIRequestHeader
    Dim BetfairGL As BFGlobal.BFGlobalService

    Private Sub BLogin_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Blogin.Click
        Print("*** Login ***")

        Dim oLoginReq As New BFGlobal.LoginReq
        Dim oLoginResp As New BFGlobal.LoginResp
        With oLoginReq
            .username = "YourUsername"
            .password = "YourPassword"
            .productId = 82           'For free API
        End With
        'Dim oLoginIn As New BFGlobal.loginIn(oLoginReq)
        oLoginResp = BetfairGL.login(oLoginReq)     'Call the API
        With oLoginResp
            CheckHeader(.header)
            Print("ErrorCode = " & .errorCode.ToString)
        End With
    End Sub

i'm using VS2010
firstly the complier wont have

Dim BetfairGL As new BFGlobal.BFGlobalService

because new cant by used on an interface

so i skipped the new, and hey presto, suddenly the related call

oLoginResp = BetfairGL.login(oLoginReq)

is a problem, its not expecting to be passed a BFGlobal.LoginReq it wants a BFGlobal.LoginIn.

so i was looking in the object browser and BFGlobal.BFGlobalService doesn't have a new method / is a service/ sort of made sense why i couldn't do what i wanted. But BFGlobal.BFGlobalServiceClient did and looked like what i needed.

so i swapped

Dim BetfairGL As new BFGlobal.BFGlobalService
for
Dim BetfairGL As new BFGlobal.BFGlobalServiceClient

and it seemed to work. Is this me doing something wrong or have they changed it since the first page was written?

Thanks
Tim

[Grantay.]

Humble thanks to Mumbles

While we are doing backslaps and handshakes, I too must offer my most sincere thanks to Mumbles for this thread.

Like bigsprout I have "hastened slowly" and built a solid app that does what I want and need.

Not only is the information valuable, accurate and informative, Mumbles has shown infinite patience with a range of requests from users wanting a "quick answer" without going though the thread diligently, to the quite complex intricate detail of the often very confusing object structure that is the BF API. One huge advantage this tutorial provides is the confidence to launch in to the other functions and build on the overall template provided here.

One series of Mumbles functions alone - PricetoInc and the reverse saved me hours of thinking and programming - it was a simple plug in!

I come from an Access VBA environment so vb.net was a major leap foward; I hope one day to have the depth of understanding you have Mumbles that you have so generously provided here for all to devour and learn from.

grantay (Canberra Australia)

[calypsored]

Thanks guys

Mumbles, Grantay and Bigsprout - you can probably deduce that arrays frazzle my brain. I tried lots of different traps but not .length (associating that as I did with string length...).

Thanks for your help.

And I'd like to echo BigSprout's comments about the thread. I too now have an application doing exactly what I wanted it to do, and couldn't have done it without this thread. I look forward to fine tuning it now - and am sure I'll be back with other daft questions sooner or later!