Beginning Visual Basic 2005 (2006)

Appendix D

Public Class Server

Inherits MarshalByRefObject

Public ReadOnly Property ServerTime() As String

Get

Return Now().ToShortTimeString

End Get

End Property

Public ReadOnly Property ServerDate() As Date

Get

Return Now().Date

End Get

End Property

End Class

Here is an example of the server code used to register the channel and port for the Remoting engine:

Imports System.Runtime.Remoting

Imports System.Runtime.Remoting.Channels

Imports System.Runtime.Remoting.Channels.Tcp

Module Module1

Sub Main()

Dim channel As TcpChannel = New TcpChannel(8500)

ChannelServices.RegisterChannel(channel)

RemotingConfiguration.RegisterWellKnownServiceType( _

GetType(Chapter20Exercise2.Server), “Engine”, _

WellKnownObjectMode.SingleCall)

Console.Write(“Engine Registered.” + Environment.NewLine)

Console.Write(“Server Active . . .”)

Console.Read()

End Sub

End Module

Remember that for the server and client you also have to add a reference to System.Runtime.Remoting and to the server class you created. The final part of the exercise was to create the client. Your code will look similar to this:

Sub Main()

Dim client As Chapter20Exercise2.Server

Console.Write(“Trying to obtain Type from Server . . .” + Environment.NewLine) client = CType(Activator.GetObject(GetType(Chapter20Exercise2.Server), _

“tcp://Maincpu:8500/Engine”), Chapter20Exercise2.Server) Console.Write(“Type Created and returned” + Environment.NewLine) Console.Write(“Server date: “ + client.ServerDate + Environment.NewLine) Console.Write(“Server time: “ + client.ServerTime + Environment.NewLine) Console.Read()

End Sub

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Solutions

After creating the client, make sure that you start the project that registers and starts the server. If you used a console application to test your server, you saw a command window with the return values from the remoting object. Congratulations, you have just created a Remoting system.

Chapter 21 Exercise Solutions

Exercise 1

For this example, you created a setup project for Notepad. We created a new setup project named Chapter21Exercise1. Under the Application folder, we browsed for and added the notepad.exe file. After adding the file, we created a shortcut to the executable and moved the shortcut to User’s Program. Menu. Next, we selected the project in Solution Explorer and then found and changed the author and manufacturer properties in the Properties window. Finally, we built and then ran the setup.exe file.

You may be asking why we changed the author and manufacturer properties. The manufacturer is used to determine the default location for the installed application. When we installed the application, C:\Program Files\Wrox\Chapter21Exercise1\ was the default installation directory. Without updating the manufacturer, the default directory would have been C:\Program Files\Default Company Name\Chapter21Exercise1\. The second reason to change the manufacturer was the support info screen under Add/Remove Programs. When you look at your application’s support info screen, you’ll see that the publisher is Wrox.

Exercise 2

In the completed exercise, you would have added a bitmap image to the application. You should have added the image to the application folder or a subfolder of the application folder. Next, you would have added a splash screen via the user interface editor. The SplashBitmap property of the Splash dialog box was changed to the bitmap you added, and the dialog box was moved up to the first screen shown. When you ran the installation, you saw the splash screen as the first dialog box.

Chapter 22 Solution

This exercise has numerous correct answers. If you ask 10 programmers to complete it, you will get 10 different answers. So, if your changes work, you have a valid answer. The following is what we came up with to solve the problem.

You need to add a call to the new function, ComputerPlayToWin, from ComputerPlay. It should be the first call in the procedure. If you find a win here and make a move, you can exit the subroutine without allocating any of the local variables in ComputerPlay.

Sub ComputerPlay()

If ComputerPlayToWin() Then Exit Sub

Your solution will look different from ours. Compare your solution to ours and see which you think is better. The first function, CheckForWin, allows you to check an entire row or column of buttons for a

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Appendix D

chance to win. If two squares are marked and the third is empty, the computer will make this move by changing the text for all buttons. This is done by passing the buttons ByRef to the function.

ComputerPlayToWin calls this function for every row, column, or diagonal win possibility on the board.

Private Function CheckForWin(ByRef btnFirst As Windows.Forms.Button, _ ByRef btnSecond As Windows.Forms.Button, ByRef btnThird As _ Windows.Forms.Button, ByVal stringToFind As String, _

ByVal strOpponentsMark As String) As Boolean Dim intSum As Int16 = 0S

‘Check to see if we can win on this row

‘We can we if we have two marks and no opponent marks on the row ‘If there is an opponents mark we are blocked so return false

If btnFirst.Text = stringToFind Then intSum += 1S

ElseIf btnFirst.Text = strOpponentsMark Then Return False

End If

If btnSecond.Text = stringToFind Then intSum += 1S

ElseIf btnSecond.Text = strOpponentsMark Then Return False

End If

If btnThird.Text = stringToFind Then intSum += 1S

ElseIf btnThird.Text = strOpponentsMark Then Return False

End If

‘We will win on this turn

‘so just mark the entire row to save some resources

If intSum = 2 Then btnFirst.Text = stringToFind

btnSecond.Text = stringToFind btnThird.Text = stringToFind Return True

Else

Return False End If

End Function

All that the ComputerPlayToWin function does is pass the buttons and strings to check CheckForWin for each possible win. If a win is found, the game is over. The computer will not make a random play if it can win.

Private Function ComputerPlayToWin() As Boolean

If CheckForWin(btn00, btn01, btn02, “O”, “X”) Then

‘Winner on top Row Call Winner(“0”)

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Solutions

Return True End If

If CheckForWin(btn10, btn11, btn12, “O”, “X”) Then ‘Winner on middle Row

Call Winner(“O”) Return True

End If

If CheckForWin(btn20, btn21, btn22, “O”, “X”) Then ‘Winner on third Row

Call Winner(“O”) Return True

End If

If CheckForWin(btn00, btn10, btn20, “O”, “X”) Then ‘Winner on first column

Call Winner(“O”) Return True

End If

If CheckForWin(btn01, btn11, btn21, “O”, “X”) Then ‘Winner on second column

Call Winner(“O”) Return True

End If

If CheckForWin(btn02, btn12, btn22, “O”, “X”) Then ‘Winner on third column

Call Winner(“O”) Return True

End If

If CheckForWin(btn00, btn11, btn22, “O”, “X”) Then ‘Winner on diagonal top left to bottom right Call Winner(“O”)

Return True End If

If CheckForWin(btn20, btn11, btn02, “O”, “X”) Then ‘Winner on diagonal bottom left to top right Call Winner(“O”)

Return True End If

End Function

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Address List project example

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