Using VB2008 to acccess the Betfair API: A tutorial

**Mumbles0** · 30-09-2010, 03:48 AM

Reply to ribogio7 (re: Profit & Loss)

The values shown near each runner name are the profit & loss values. These are the amount you would win (or lose) if that particular runner were to win the event.

The API call getMarketProfitAndLoss returns a set of values, but it only takes into account your matched bets. The website shows the IfWin values for proposed (unsubmitted) bets. Neither of these sets are particularly useful if you want to assess your current situation if you have several bets (matched, unmatched and proposed) on a market, so it�s probably best to calculate your own values. At least that way you know what you're getting.

For each runner:

IfWin = Total profits from back bets on this runner - Total losses from lay bets on this runner
- Total amount of back bets on other runners + Total amount of lay bets on other runners

Here is an idea to calculate the IfWin values:

Define a class (say, BetInfo) to hold details of each bet on the market:

Code:

Class BetInfo   'A class for bet details
  Property price As Decimal
  Property amount As Decimal  'Use + for back, - for lay
  
  'Other bet properties
  
  End Class

Use this class for both back and lay bets, but use +ve amounts for Back, and -ve amounts for Lay. This will simplify the calculations. For example:

Bet1.amount = 5 for a Back bet
Bet1.amount = -5 for a Lay bet

When you place a bet add an instance of this class to a separate bet List for each runner to model the bets on the market. Hold the Lists for all the runners in an array (say, Bets()).

An algorithm the calculate the IfWin values for each runner is this:

Code:

Dim Bets() As List(Of BetInfo), IfWin() As Decimal, i, j, k, m As Integer

  'Build the array of bet lists
  '.....
  
  m = Bets.Count - 1   'The number of runners - 1
  ReDim IfWin(m)       'An array to hold the profit(or loss) values for each runner
  
  For i = 0 To m   'For each runner
    For j = 0 To m    'Look at all runners
      For k = 0 To Bets(j).Count - 1  'For each bet on this runner
        With Bets(j)(k)
          If j = i Then 'Runner is winner
            IfWin(i) += .amount * (.price - 1)  'Accumulate totals
          Else  'Other runners
            IfWin(i) += -.amount
          End If
        End With
      Next
    Next
  Next

It�s up to you what bets are added to the bet lists - matched, unmatched or proposed. Bear in mind that unmatched bets may not, of course, be matched at the desired price.

**granted** · 30-09-2010, 12:27 PM

keydown problem...anyone know about keydown stuff?

i have 2 checkboxes

all i want to do is:

if i press the letter Z it selects checkbox 2 otherwise checkbox 1 is selected

it tried this, but nothing happens

Code:

Private Sub Form1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown
        Me.KeyPreview = True
        If e.KeyCode = Keys.Z Then
            Me.RadioButton1.Checked = True
            Me.RadioButton2.Checked = False

        Else
            Me.RadioButton1.Checked = False
            Me.RadioButton2.Checked = True
        End If
    End Sub

**Mumbles0** · 30-09-2010, 01:49 PM

granted,

Set the KeyPreview property to True in the properties window for Form1 before you run the project.

**bingobuddha** · 30-09-2010, 08:03 PM

I've had a reasonable scan throughout this post to see if it was going to be any use to me and have to say that Mumbles0 must be approaching sainthood by now. Firstly many thanks just for imparting your knowledge but what impresses me most is your patience with mere mortals trying to understand. You seem to have answered any question posed and in such an understanding way with no hint patronising, hats off to you.

BTW this was exactly what I was hoping to find .... only trouble now is I have to start writing some code aaarrrggghhh!!!!!! World beware ( or should I rephrase with ' Mumbles0 Prepare ').

**granted** · 01-10-2010, 06:23 AM

keydown problem...#2

what happens if the form doesn't exist..like when we made the buttons(i) form for the buttons....

i.e. i cant see this form in the properties box...

can i set in the code somehow so when i load up the form it always has keypreview = true?

**iraklis35** · 01-10-2010, 12:31 PM

Originally posted by Mumbles0 View Post

The values shown near each runner name are the profit & loss values. These are the amount you would win (or lose) if that particular runner were to win the event.

The API call getMarketProfitAndLoss returns a set of values, but it only takes into account your matched bets. The website shows the IfWin values for proposed (unsubmitted) bets. Neither of these sets are particularly useful if you want to assess your current situation if you have several bets (matched, unmatched and proposed) on a market, so it�s probably best to calculate your own values. At least that way you know what you're getting.

For each runner:

IfWin = Total profits from back bets on this runner - Total losses from lay bets on this runner
- Total amount of back bets on other runners + Total amount of lay bets on other runners

Here is an idea to calculate the IfWin values:

Define a class (say, BetInfo) to hold details of each bet on the market:

Code:

Class BetInfo   'A class for bet details
  Property price As Decimal
  Property amount As Decimal  'Use + for back, - for lay
  
  'Other bet properties
  
  End Class

Use this class for both back and lay bets, but use +ve amounts for Back, and -ve amounts for Lay. This will simplify the calculations. For example:

Bet1.amount = 5 for a Back bet
Bet1.amount = -5 for a Lay bet

When you place a bet add an instance of this class to a separate bet List for each runner to model the bets on the market. Hold the Lists for all the runners in an array (say, Bets()).

An algorithm the calculate the IfWin values for each runner is this:

Code:

Dim Bets() As List(Of BetInfo), IfWin() As Decimal, i, j, k, m As Integer

  'Build the array of bet lists
  '.....
  
  m = Bets.Count - 1   'The number of runners - 1
  ReDim IfWin(m)       'An array to hold the profit(or loss) values for each runner
  
  For i = 0 To m   'For each runner
    For j = 0 To m    'Look at all runners
      For k = 0 To Bets(j).Count - 1  'For each bet on this runner
        With Bets(j)(k)
          If j = i Then 'Runner is winner
            IfWin(i) += .amount * (.price - 1)  'Accumulate totals
          Else  'Other runners
            IfWin(i) += -.amount
          End If
        End With
      Next
    Next
  Next

It�s up to you what bets are added to the bet lists - matched, unmatched or proposed. Bear in mind that unmatched bets may not, of course, be matched at the desired price.

Can you give me an example of creating 'Build the array of bet lists'

**Mumbles0** · 01-10-2010, 01:10 PM

Form1_KeyDown

granted,

In Step 29 we put the buttons on a new instance of the MarketForm form.

Sounds like you need to become more familiar with the IDE. In the Solution Explorer select "Form1.vb", then click the "View Designer" icon to show the "Form1.vb [Design]" tab. Look for the "Properties" window. If it's not there, open the "View" menu and select "Properies Window". Now if you click on Form1, its properties will appear in this window. What more can I say?

Alternatively, you can set the KeyPreview property at run time. A good place to do this in the Form1_Load event. This event fires the first time the form is shown.

Code:

Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
  Me.KeyPreview = True
End Sub

Private Sub Form1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown
  If e.KeyCode = Keys.Z Then
    Me.RadioButton1.Checked = True
    Me.RadioButton2.Checked = False
  Else
    Me.RadioButton1.Checked = False
    Me.RadioButton2.Checked = True
  End If
End Sub

**Mumbles0** · 05-10-2010, 10:16 AM

Reply to iraklis35 (re: Bet Lists)

Building an array of bet lists is very application-specific and I can�t post a simple example for the case where many bets are placed on a single market. Perhaps the profit/loss example I�ve shown oversimplifies the situation.

You could hold runner data in a class (or some other data structure, even a DataGridView), which included the Bets list, for example:

Code:

Class RunnerData
  Property RunnerName As String
  Property SelectonId As Integer
  'other properties (prices, etc.)
  Property Bets() As List(Of BetInfo)  'The bet list 
End Class

For the market you would set up an array of RunnerData after calling getMarket.

You call getMUBets to monitor your bets. You then consider each bet in turn, building the bet lists for each runner as you go. Do something like this:

For each bet in the .bets array returned by getMUbets:

1. Determine the index in the element in the array of RunnerData matching the selectionId.

2. Add a new bet object containing the bet price and amount to the Bets list for this runner using the .add method

This is a simple view of what is required. You might want code to select matched and/or unmatched bets. Also you may want to somehow include a proposed bet to provide a �what if you placed this new bet� scenario. This would have to link into you bet placement UI.

**Krandall** · 06-10-2010, 11:11 AM

Get Lay & Back Prices with Section Name

Hi,

I am using betfair api, I read market data with getAllMarket function which returns whole market data per sport as I select (Calico - 1) for Soccer and using UnpackMarket , Now I want to read Lay & Back Prices with Secion for each market.

Please help me out. How to do it.

Many Thanks

**Mumbles0** · 07-10-2010, 09:40 AM

Krandall,

From the getAllMarkets call you obtain the marketId for the market you are interested in. With this marketId you can call getMarket to get the runners and their selectionIds, then call getMarketPricesCompressed to get back and lay prices. See Step 12 and Step 14.

**iraklis35** · 07-10-2010, 10:19 AM

Example from my code

Originally posted by iraklis35 View Post

Can you give me an example of creating 'Build the array of bet lists'

I get this error when set Betinfo class

'ERROR Warning
'Bets' is used before it has been assigned a value. A null reference exception could result at runtime. My purpose is to calculate profit and loss before assign any bet. In my bet tab before assign, i can have multiple bets for a lot of runners scenario. How can i do that.

This is my code

Public Class BetInfo 'A class for bet details

Private mPrice As Decimal
Private mAmount As Decimal
Private mId As String
Private mType As BFUK.BetTypeEnum
Public Property type() As BFUK.BetTypeEnum
Get
Return mType
End Get
Set(ByVal value As BFUK.BetTypeEnum)
mType = value

End Set
End Property
Public Property price() As Decimal
Get
Return mPrice
End Get
Set(ByVal value As Decimal)
mPrice = value

End Set
End Property
Public Property amount() As Decimal 'Use + for back, - for lay
Get
Return mAmount
End Get
Set(ByVal value As Decimal)
mAmount = value

End Set
End Property
Public Property Id() As String 'Use + for back, - for lay
Get
Return mId
End Get
Set(ByVal value As String)
mId = value

End Set
End Property

'Other bet properties

End Class

Sub calc_profitAndLossBeforePlace()

Dim Bets() As List(Of BetInfo)

Dim IfWin() As Decimal

Dim i, j, k, m As Integer

Dim d As New BetInfo
'Build the array of bet lists

Dim Req As New BFUK.GetMUBetsReq
Dim Resp As New BFUK.GetMUBetsResp
With Req
.header = oHeaderUK() 'The standard header
.marketId = Val(txt_marketid.Text) 'The market of interest
.betStatus = BFUK.BetStatusEnum.MU 'Return status of matched and unmatched bets
.recordCount = 100 'Max 100 bets
End With

Resp = BetFairUK.getMUBets(Req)
k = 0

'Fill Bets() with the Matched Bets

Try
With Resp
CheckHeader(.header)
'Print("ErrorCode = " & .errorCode.ToString)
If .errorCode = BFUK.GetMUBetsErrorEnum.OK Then

'ctr.lbl_selection_name.Text
'ctr.lbl_profit.Text
'MsgBox(.bets(k).selectionId.ToString)
'.bets(k).selectionId
For i = 0 To .bets.Length - 1 'For all bets on the market
With .bets(i)
d.Id = .selectionId.ToString
If .betStatus = BFUK.BetStatusEnum.M Then
If .betType = BFUK.BetTypeEnum.B Then
d.price = .price
d.amount = .size
Else
d.price = .price
d.amount = -.size
End If
End If

End With

Next
Bets(i).Add(d)

'ERROR Warning
'Bets' is used before it has been assigned a value. A null reference exception could result at runtime. C:\betfair\BetApis\BetApis\MainForm.vb 4240 21 BetApis

End If

End With

Catch ex As Exception
Print(ex.Message)
End Try

'FIll the BETS() from going to bet Panel
For Each ctr As AddBet In Panel_bet_tab1.Controls

If ctr.GroupBox1.Text = "ΥΠΕΡ" Then
d.price = ctr.Nud_apodosi.Value
d.amount = ctr.nud_axia.Value
d.Id = ctr.lbl_selectioname.Tag
Else
d.price = ctr.Nud_apodosi.Value
d.amount = -ctr.nud_axia.Value
d.Id = ctr.lbl_selectioname.Tag
End If
Bets(i).Add(d)
i += 1

Next

For i = 0 To Bets.Count - 1
MsgBox(Bets(i).ToString)
Next

m = Bets.Count - 1 'The number of runners - 1
ReDim IfWin(m) 'An array to hold the profit(or loss) values for each runner

For i = 0 To m 'For each runner
For j = 0 To m 'Look at all runners
For k = 0 To Bets(j).Count - 1 'For each bet on this runner
With Bets(j)(k)
MsgBox("Bets(" + j.ToString + ")(" + k.ToString + ") Id:" + .Id.ToString + " Apodosi:" + .price.ToString + " Poso:" + .amount.ToString)
If j = i Then 'Runner is winner
IfWin(i) += .amount * (.price - 1) 'Accumulate totals
Else 'Other runners
IfWin(i) += -.amount
End If
End With
Next
Next
Next
End Sub

**Mr.Anderson** · 09-10-2010, 04:46 PM

Application security

Thank you Mumbles0 for a very nice tutorial! Easy to follow even for a novice like myself. But since I am a novice and Visual Studio does so much coding for us I really do not understand much of what is going on behind the scenes. Specifically is there anything to be concerned about from a security standpoint?
Is it reasonably safe (as safe as it is to use a standard web browser) to use applications based on this test application to communicate with Betfair? For example is my username and password encrypted/sent over a secure channel from my computer to Betfair? One thing I know I would change is that I would not store my username and password locally in plain text. Would appreciate input on this matter from Mumbles0 or any other experienced programmer.

**Monairda** · 09-10-2010, 11:18 PM

Handling async calls for multiple markets

Hello everyone

Mumbles long ago gave me a solution calls for multiple async Handling Markets

http://forum.bdp.betfair.com/showthr...?t=112&page=33

Now I would like to find another way to handling async calls for multiples markets without using a form for each market. It could be done using a tab for each market in one form? How?

Any help, please?

**monkeymagix** · 11-10-2010, 01:15 AM

Cannot get getMUBets working.

First off I would just like to thank the author of this series for such a great explaination of the Betfair API. It has proved to be invaluable and I have used it as the guide to creating my own C# console bot.

Now my own system requires that each bet is stored in a table in my database with any corresponding relationship to a parent bet (so that I can
do accumulators). Once the bet is placed I store the BetID in this table so that I can update it later once I know the outcome. However along
with many people it seems I am having problems with the concept of partially matched bets as this could theoretically lead me to have multiple
rows in my table with the same BetID but different bet amounts and prices etc.

I do have a unique BetPK primary key on the table so I could do a SUM on all matched parts of the bet but I am stuck on how to collect all these parts
to store them. From what I have read I should be using getMUBets and not getBet to ensure I get all parts of a bet however I am having problems getting the code to work.

As a test I have just placed a back bet at stupidly high odds which remains unmatched and whilst I can run the following code with the relevant
betID to find out it's unmatched:

Code:

public void GetBetStatus(long betId)
{
    
    BFUK.GetBetReq Req = new BetfairBOT.BFUK.GetBetReq();

    Req.header = oHeaderUK();
    Req.betId = betId;

    BFUK.GetBetResp Resp = BetfairUK.getBet(Req);
    
    CheckHeader(Resp.header);
    
    if (Resp.errorCode == BFUK.GetBetErrorEnum.OK)
    {

	if (Resp.bet.betStatus == BetfairBOT.BFUK.BetStatusEnum.S)
	{

	    // settled - did we win
	    if (Resp.bet.profitAndLoss > 0)
	    {
		Program.ShowMsg("The bet: " + betId.ToString() + " has been settled and resulted in a profit of " + Resp.bet.profitAndLoss.ToString());
	    }
	    else
	    {
		Program.ShowMsg("The bet: " + betId.ToString() + " has been settled and resulted in a loss of " + Resp.bet.profitAndLoss.ToString());
	    }
	}
	else if (Resp.bet.betStatus == BetfairBOT.BFUK.BetStatusEnum.M)
	{
	    Program.ShowMsg("The bet: " + betId.ToString() + " has been matched at price " + Resp.bet.matchedSize.ToString());
	}
	else if (Resp.bet.betStatus == BetfairBOT.BFUK.BetStatusEnum.U)
	{
	    Program.ShowMsg("The bet: " + betId.ToString() + " has not been matched");
	}
	else if (Resp.bet.betStatus == BetfairBOT.BFUK.BetStatusEnum.C)
	{
	    Program.ShowMsg("The bet: " + betId.ToString() + " was cancelled");
	} 
    } 

}

when I try to use getMUBets (as its suggested to do) I cannot get the same info back and I just recieve the NO_RESULTS error code which is obviously
wrong as the bet definitely exists. I have tried this method by supplying only a market ID and just a bet ID but they both return the same error.

Code:

public void GetMUBetStatus(long betId)
{
    BFUK.GetMUBetsReq Req = new BFUK.GetMUBetsReq();
    Req.header = oHeaderUK();

    // tried with a market ID but no luck - comment out when using the betId
    Req.marketId = 101826566;
    Req.recordCount = 10;

   /*  OR	*/
    Req.betIds = new long[1];
    Req.betIds[0] = betId;     
    Req.betStatus = BFUK.BetStatusEnum.MU;

    BFUK.GetMUBetsResp Resp = BetfairUK.getMUBets(Req);

    CheckHeader(Resp.header);

    Program.ShowMsg("ErrorCode: " + Resp.errorCode.ToString());

    if (Resp.errorCode == BFUK.GetMUBetsErrorEnum.OK)
    {
	for(int i = 0; i < Resp.bets.Length - 1; i++)
	{
	    Program.ShowMsg("BetID: " + Resp.bets[i].betId.ToString() + " - Status: " + Resp.bets[i].betStatus + " - Price: " + Resp.bets[i].price);
	}                
       
    }

}

Can anyone see what I am doing wrong in terms of the getMUBets function?

Also is there a testmode within the Betfair API so that I can simulate the placing of partially matched bets as I cannot think of any other
way to simulate this situation to test for it correctly? How have other people solved this problem?

Also am I right in the following assumptions regarding this scenario

-I place a �100 back bet at 20/1
-�50 is matched at that price creating 2 bets with the same ID. One part has the status of U the other M.
-If the remaining �50 is matched later on does this become two separate bets with different Bet IDs? Or does it remain as one bet with one Bet ID
but two parts each with a status of M?
-Also do I get two transaction IDs for each part of the bet or is this shared as well
-If both parts are successful and pay off does this become one settled bet or remain as multiple parts with the same Bet ID

The main problem is that I need to know the best way of identifying individual bets and storing them in my database so that I can check
a) the whole bet amount I wanted to place on a selection has been matched (one way or another)
b) I can easily check whether the bet on the selection was successful once settled.

When I check to see if the bet has paid out once it has been settled I am guessing that my first GetBetStatus function isn't good enough unless the individual matched parts are joined back up again to hold the total profit for a bet. Otherwise I would need to loop through all the sections using another method.

Apart from this one problem my own bot is 99% ready so it is something I really need to get my head round.

The bot is a console application and doesn't need to make async calls as the number of transactions it will make a day will be pretty minimal as its not a high frequency trader bot. Any good example code would be much appreciated.

Thanks

**Mumbles0** · 14-10-2010, 01:15 PM

Reply to Iraklis35 (Build Bet Lists)

Let�s take one thing at a time, the statement:

Bets(i).Add(d)

will cause the error because Bets is nothing. It must first be initialized with some code like this:

Code:

    ReDim Bets(n - 1)
    For i = 0 To n - 1
      Bets(i) = New List(Of BetInfo)
    Next

where n is the number of runners in the market.

The profit & loss code must integrate closely with your application. For the market of interest you will have some type of data structure (perhaps a DataGridView control) which holds runner data (names, selectionIds, etc.) obtained from a getMarket call. The bet lists should be incorporated within this structure, with each runner having its own bet list.

You must have the runner data set up properly before you look at profit & loss calculation. I don�t know what you have...

Using VB2008 to acccess the Betfair API: A tutorial

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