По второму варианту, в панели Solution Explorer выполняем правый щелчок по имени проекта и в контекстном меню выбираем Add, New Item, в панели Add New Item выделяем шаблон Code File, в окне Name записываем имя Block.vb и щёлкаем кнопку Add. В проект (и в панель Solution Explorer) добавляется этот файл, открывается пустое окно редактирования кода, в которое записываем код со следующего листинга.
Листинг 20.16. Новый файл.
Imports System.Drawing.Drawing2D
'''
''' This class represents one of the balls in the game grid.
'''
'''
Public Class Block
Public Const BlockSize As Integer = 25
Private colorValue As Color
Private deletionValue As Boolean = False
Private Shared rand As New Random
Public Property Color() As Color
Get
Return colorValue
End Get
Set(ByVal Value As Color)
colorValue = Value
End Set
End Property
Public Property MarkedForDeletion() As Boolean
Get
Return deletionValue
End Get
Set(ByVal Value As Boolean)
deletionValue = Value
End Set
End Property
Public Sub New(ByVal newColor As Color)
colorValue = newColor
End Sub
Public Sub New(ByVal colors() As Color)
Dim ncolors As Integer = colors.Length
Dim pickedColor As Integer
pickedColor = rand.Next(0, ncolors)
colorValue = colors(pickedColor)
End Sub
Public Sub Draw(ByVal graphics As Graphics, ByVal point As Point)
Dim brush As System.Drawing.Drawing2D.LinearGradientBrush = _
CreateTheBrush(point)
DrawTheCircle(graphics, brush, point)
End Sub
Private Sub DrawTheCircle(ByVal graphics As Graphics, _
ByVal brush As LinearGradientBrush, ByVal location As Point)
Dim topleft As Point = location
Dim bottomright As Point = New Point(location.X + _
BlockSize, location.Y + BlockSize)
Dim transTopLeft As Point = PointTranslator.TranslateToBL( _
topleft)
Dim transBottomRight As Point = _
PointTranslator.TranslateToBL(bottomright)
Dim transwidth As Integer = transBottomRight.X transTopLeft.X
Dim transheight As Integer = _
transBottomRight.Y transTopLeft.Y
graphics.FillEllipse(brush, New Rectangle(transTopLeft, _
New Size(transwidth, transheight)))
End Sub
Private Function CreateTheBrush(ByVal location As Point) As _
LinearGradientBrush
Dim transLocation As Point = _
PointTranslator.TranslateToBL(location)
Dim brushpt1 As Point = transLocation
Dim brushpt2 As New Point(transLocation.X + Block.BlockSize _
+ 4, transLocation.Y BlockSize 4)
Dim brush As New LinearGradientBrush(brushpt1, _
brushpt2, Me.Color, System.Drawing.Color.White)
Return brush
End Function
End Class
По второму варианту, в панели Solution Explorer выполняем правый щелчок по имени проекта и в контекстном меню выбираем Add, New Item, в панели Add New Item выделяем шаблон Code File, в окне Name записываем имя Grid.vb и щёлкаем кнопку Add. В проект (и в панель Solution Explorer) добавляется этот файл, открывается пустое окно редактирования кода, в которое записываем код со следующего листинга.
Листинг 20.17. Новый файл.
'''
''' This class represents the grid of blocks. It handles most of
''' the game play.
'''
'''
Public Class Grid
' The grids is 12 columns and 15 rows of Block objects.
Dim matrix(11, 14) As Block
'''
''' Creates a few rows of blocks to start the game.
''' Game starts with Red, Blue, and Green blocks.
'''
''' Number of rows of blocks to create
''' to start the game.
'''
Public Sub New(ByVal nrows As Integer)
If nrows > matrix.GetLength(0) Then
Throw New Exception("Must start with " & _
matrix.GetLength(0) & " or fewer rows.")
End If
Dim row As Integer
Dim column As Integer
For row = 0 To nrows 1
For column = 0 To matrix.GetLength(1) 1
matrix(row, column) = New Block( _
New Color() {Color.Red, Color.Blue, Color.Green})
Next
Next
For row = nrows To matrix.GetLength(0) 1
For column = 0 To matrix.GetLength(1) 1
matrix(row, column) = Nothing
Next
Next
End Sub
'''
''' A new row may be added at any time. New rows have Gray
''' blocks in addition
''' to Red, Blue, and Green. This makes the game more difficult.
'''
'''
Public Sub AddRow()
Dim column As Integer
' Add a new block to each column.
For column = 0 To matrix.GetLength(1) 1
Dim newBlock As New Block(New Color() _
{Color.Red, Color.Blue, Color.Green, Color.Gray})
' Add the new block at the botttom of the column,
' and push the rest of the
' blocks up one column.
For row As Integer = matrix.GetLength(0) 1 To 1 Step -1
matrix(row, column) = matrix(row 1, column)
Next
matrix(0, column) = newBlock
Next
End Sub
'''
''' Draw the grid of blocks
'''
'''
'''
'''
Public Sub Draw(ByVal graphics As Graphics, _
ByVal backColor As Color)
graphics.Clear(backColor)
Dim row As Integer
Dim column As Integer
Dim theBlock As Block
For row = 0 To matrix.GetLength(0) 1
For column = 0 To matrix.GetLength(1) 1
theBlock = matrix(row, column)
If Not theBlock Is Nothing Then
Dim pointA As New Point( _
column * Block.BlockSize, _
row * Block.BlockSize)
matrix(row, column).Draw(graphics, pointA)
End If
Next
Next
End Sub
'''
''' This method responds to a click event in the UI.
'''
'''
'''
'''
Public Function Click(ByVal point As Point) As Integer
' Figure out row and column.
Dim total As Integer
Dim transPt As Point = PointTranslator.TranslateToTL(point)
Dim selectedRow As Integer = transPt.Y \ Block.BlockSize
Dim selectedColumn As Integer = transPt.X \ Block.BlockSize
Dim selectedBlock As Block = matrix(selectedRow, _
selectedColumn)
If Not selectedBlock Is Nothing Then
selectedBlock.MarkedForDeletion = True
' Determine if any of the neighboring blocks are
' the same color.
FindSameColorNeighbors(selectedRow, selectedColumn)
' Determine how many blocks would be eliminated.
total = Me.CalculateScore()
If total > 1 Then
Me.CollapseBlocks()
Else
Me.ClearMarkedForDeletion()
End If
End If
Return total
End Function
Private Sub ClearMarkedForDeletion()
Dim row As Integer
Dim column As Integer
For column = matrix.GetLength(1) 1 To 0 Step -1
' If column is completely empty, then move everthing
' down one.
For row = 0 To matrix.GetLength(0) 1
If Not matrix(row, column) Is Nothing Then
matrix(row, column).MarkedForDeletion = False
End If
Next
Next
End Sub
'''
''' Find out how many blocks will be eliminated.
'''
'''
'''
Private Function CalculateScore() As Integer
Dim row As Integer
Dim column As Integer
Dim total As Integer = 0
For column = matrix.GetLength(1) 1 To 0 Step -1
' If column is completely empty, then move everthing
' down one.
For row = 0 To matrix.GetLength(0) 1
If Not matrix(row, column) Is Nothing Then
If matrix(row, column).MarkedForDeletion Then
total += 1
End If
End If
Next
Next
Return total
End Function
'''
''' After the blocks are removed from the columns, there may be
''' columns that are empty. Move columns from right to left to
''' fill in the empty columns.
'''
'''
Public Sub CollapseColumns()
Dim row As Integer
Dim column As Integer
For column = matrix.GetLength(1) 1 To 0 Step -1
' If column is completely empty, then all the columns
' over one.
Dim noBlocks As Boolean = True
For row = 0 To matrix.GetLength(0) 1
If Not matrix(row, column) Is Nothing Then
noBlocks = False
End If
Next
If noBlocks Then
Dim newcol As Integer
For newcol = column To matrix.GetLength(1) 2
For row = 0 To matrix.GetLength(0) 1
matrix(row, newcol) = matrix(row, newcol + 1)
Next
Next
newcol = matrix.GetLength(1) 1
For row = 0 To matrix.GetLength(0) 1
matrix(row, newcol) = Nothing
Next
End If
Next
End Sub
'''
''' Remove all the blocks from the grid.
'''
'''
Public Sub CollapseBlocks()
Dim theBlock As Block
Dim column As Integer
Dim row As Integer
Dim aRow As Integer
' First remove the blocks from each column.
For column = 0 To matrix.GetLength(1) 1
For row = matrix.GetLength(0) 1 To 0 Step -1
theBlock = matrix(row, column)
If (Not theBlock Is Nothing) Then
If theBlock.MarkedForDeletion Then
For aRow = row To matrix.GetLength(0) 2
matrix(aRow, column) = _
matrix(aRow + 1, column)
Next
matrix(matrix.GetLength(0) 1, _
column) = Nothing
End If
End If
Next
Next
' Reset the MarkedForDeletion flags.