''' 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.
''' </summary>
''' <remarks></remarks>
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
''' <summary>
''' Draw the grid of blocks
''' </summary>
''' <param name="graphics"></param>
''' <param name="backColor"></param>
''' <remarks></remarks>
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
''' <summary>
''' This method responds to a click event in the UI.
''' </summary>
''' <param name="point"></param>
''' <returns>The number of blocks removed from the grid.</returns>
''' <remarks></remarks>
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
''' <summary>
''' Find out how many blocks will be eliminated.
''' </summary>
''' <returns></returns>
''' <remarks></remarks>
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
''' <summary>
''' 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.
''' </summary>
''' <remarks></remarks>
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
''' <summary>
''' Remove all the blocks from the grid.
''' </summary>
''' <remarks></remarks>
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.
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
theBlock.MarkedForDeletion = False
End If
Next
Next
' Remove any columns that are now empty.
CollapseColumns()
End Sub
''' <summary>
''' Provides access into the grid.
''' </summary>
''' <param name="row"></param>
''' <param name="column"></param>
''' <value></value>
''' <remarks></remarks>
Default Public Property Item(ByVal row As Integer, _
ByVal column As Integer) As Block
Get
Return matrix(row, column)
End Get
Set(ByVal Value As Block)
matrix(row, column) = Value
End Set
End Property
Private blocksToExamine As ArrayList
''' <summary>
''' Set MarkedForDeletion to True for each neighboring block
''' of the same color.
''' </summary>
''' <param name="row"></param>
''' <param name="column"></param>
''' <remarks></remarks>
Private Sub FindSameColorNeighbors(ByVal row As Integer, _
ByVal column As Integer)
Dim color As Color = matrix(row, column).Color
blocksToExamine = New ArrayList
blocksToExamine.Add(New Point(row, column))
matrix(row, column).MarkedForDeletion = True
' Each time you find a neighbor, mark it for deletion, and
' add it to the list of blocks to look for neighbors.
' After you
' examine it, remove it from the list. Keep doing this
' until there are no more blocks to look at.
While blocksToExamine.Count > 0
FindNeighbors()
End While
End Sub
''' <summary>
''' Look to the blocks on each side.
''' </summary>
''' <remarks></remarks>
Private Sub FindNeighbors()
' Take the first block out of the arraylist and examine it.
Dim location As Point = CType(blocksToExamine(0), Point)
Dim currentBlock As Block = matrix(location.X, location.Y)
Dim row As Integer = location.X
Dim column As Integer = location.Y
blocksToExamine.RemoveAt(0)
Dim nextRow As Integer
Dim nextCol As Integer
Dim selected As Block
' look up
If row < matrix.GetLength(0) – 1 Then
nextRow = row + 1
selected = matrix(nextRow, column)
ExamineNeighbor(selected, nextRow, column, _
currentBlock.Color)
End If
' look down
If row > 0 Then
nextRow = row – 1
selected = matrix(nextRow, column)
ExamineNeighbor(selected, nextRow, column, _
currentBlock.Color)
End If
' look left
If column > 0 Then
nextCol = column – 1
selected = matrix(row, nextCol)
ExamineNeighbor(selected, row, nextCol, _
currentBlock.Color)
End If
' look right
If column < matrix.GetLength(1) – 1 Then
nextCol = column + 1
selected = matrix(row, nextCol)
ExamineNeighbor(selected, row, nextCol, _
currentBlock.Color)
End If
End Sub
''' <summary>
''' If the neighbor is the same color, add it to the blocks
''' to examine.
''' </summary>
''' <param name="selected"></param>
''' <param name="row"></param>
''' <param name="column"></param>
''' <param name="color"></param>
''' <remarks></remarks>
Private Sub ExamineNeighbor(ByVal selected As Block, _
ByVal row As Integer, ByVal column As Integer, _
ByVal color As Color)
If Not selected Is Nothing Then
If selected.Color.Equals(color) Then
If Not selected.MarkedForDeletion Then
selected.MarkedForDeletion = True
blocksToExamine.Add(New Point(row, column))
End If
End If
End If
End Sub
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 HighScore.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 20.18. Новый файл.
''' <summary>
''' Represents one high score.
''' </summary>
''' <remarks></remarks>
Public Class HighScore
Implements IComparable
Public nameValue As String
Public scoreValue As Integer
Public Property Name() As String
Get
Return nameValue
End Get
Set(ByVal Value As String)
nameValue = Value
End Set
End Property
Public Property Score() As Integer
Get
Return scoreValue
End Get
Set(ByVal Value As Integer)
scoreValue = Value
End Set
End Property
Public Overrides Function ToString() As String
Return Name & ":" & Score
End Function
Public Sub New(ByVal saved As String)
Name = saved.Split(":".ToCharArray)(0)
Score = CInt(saved.Split(":".ToCharArray)(1))
End Sub
Public Function CompareTo(ByVal obj As Object) As Integer Implements System.IComparable.CompareTo
Dim other As HighScore
other = CType(obj, HighScore)
Return Me.Score – other.Score
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 HighScores.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 20.19. Новый файл.
Imports Microsoft.Win32
''' <summary>
''' Reads and writes the top three high scores to the registry.
''' </summary>
''' <remarks></remarks>
Public Class HighScores
''' <summary>
''' Read scores from the registry.
''' </summary>
''' <returns></returns>
''' <remarks></remarks>
Public Shared Function GetHighScores() As HighScore()
Dim tops(2) As HighScore
Dim scoreKey As RegistryKey = Registry.CurrentUser. _
CreateSubKey("Software\VBSamples\Collapse\HighScores")
For index As Integer = 0 To 2
Dim key As String = "place" & index.ToString
Dim score As New HighScore(CStr(scoreKey.GetValue(key)))
tops(index) = score
Next
scoreKey.Close()
Return tops
End Function
''' <summary>
''' Update and write the high scores.
''' </summary>
''' <param name="score"></param>
''' <remarks></remarks>
Public Shared Sub UpdateScores(ByVal score As Integer)
Dim tops(3) As HighScore
Dim scoreKey As RegistryKey = Registry.CurrentUser. _
CreateSubKey("Software\VBSamples\Collapse\HighScores")
tops(0) = New HighScore(scoreKey.GetValue("Place0").ToString)
tops(1) = New HighScore(scoreKey.GetValue("Place1").ToString)
tops(2) = New HighScore(scoreKey.GetValue("Place2").ToString)
If score > tops(2).Score Then
Dim name As String = InputBox("New high score of " & _
score & " for:")
tops(3) = New HighScore(" :0")
tops(3).Name = name
tops(3).Score = score
Array.Sort(tops)
Array.Reverse(tops)
scoreKey.SetValue("Place0", tops(0).ToString)
scoreKey.SetValue("Place1", tops(1).ToString)
scoreKey.SetValue("Place2", tops(2).ToString)
End If
scoreKey.Close()
End Sub
''' <summary>
''' Set up the entries for new scores.
''' </summary>
''' <remarks></remarks>
Shared Sub SetUpHighScores()
Dim scoreKey As RegistryKey = Registry.CurrentUser. _
CreateSubKey("Software\VBSamples\Collapse\HighScores")
If scoreKey.GetValue("Place1") Is Nothing Then
scoreKey.SetValue("Place0", " :0")
scoreKey.SetValue("Place1", " :0")
scoreKey.SetValue("Place2", " :0")
End If
scoreKey.Close()
End Sub
''' <summary>
''' Reset scores.
''' </summary>
''' <remarks></remarks>
Shared Sub ResetScores()
Dim scoreKey As RegistryKey = Registry.CurrentUser. _
CreateSubKey("Software\VBSamples\Collapse\HighScores")
scoreKey.SetValue("Place0", " :0")
scoreKey.SetValue("Place1", " :0")
scoreKey.SetValue("Place2", " :0")
scoreKey.Close()
End Sub
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 PointTranslator.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 20.20. Новый файл.
''' <summary>
''' Form coordinates have the top, left as (0,0). For the game grid,
''' it is easier to have the bottom left of the grid as (0,0). This
''' translates the points.
''' </summary>
''' <remarks></remarks>
Public Class PointTranslator
Private Shared graphicsValue As Graphics
Private Shared height As Integer
Public Shared Property Graphics() As Graphics
Get
Return graphicsValue
End Get
Set(ByVal Value As Graphics)
graphicsValue = Value
height = CInt(graphicsValue.VisibleClipBounds.Height())
End Set
End Property
' Translates an (X,Y) point from the top left to
' an (X, Y) point from the bottom left.
Public Shared Function TranslateToBL(ByVal topleft As Point) _
As Point
Dim newPoint As Point
newPoint.X = topleft.X
newPoint.Y = height – topleft.Y
Return newPoint
End Function
Public Shared Function TranslateToTL(ByVal bottomleft As Point) _
As Point
Dim newPoint As Point
newPoint.X = bottomleft.X
newPoint.Y = height – bottomleft.Y
Return newPoint
End Function
End Class
После этих добавлений ( Block.vb, Grid.vb, HighScore.vb, HighScores.vb, PointTranslator.vb) в панели Solution Explorer должны быть файлы, показанные выше. Дважды щёлкая по имени файла, любой файл можно открыть, изучить и редактировать.
Теперь в наш проект добавляем переменные и методы, связанные с формой Form2 для вывода результатов игры.
Открываем файл Form2.vb (например, по схеме: File, Open, File) и в классе Form2 нашего проекта записываем следующее свойство.
Листинг 20.21. Свойство.
Public Property SoundOn() As Boolean
Get
Return Me.isSoundOn.Checked
End Get
Set(ByVal Value As Boolean)
Me.isSoundOn.Checked = Value
End Set
End Property
В панели Properties (для Form2) на вкладке Events дважды щёлкаем по имени события Load (Загрузка). Появившийся шаблон метода Form2_Load после записи нашего кода принимает следующий вид.
Листинг 20.22. Метод для загрузки результатов игры.
Private Sub Form2_Load(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles MyBase.Load
Me.DataGridView1.DataSource = HighScores.GetHighScores()
End Sub
На форме Form2 дважды щёлкаем по кнопке Button. Появляется шаблон метода (для очистки таблицы результатов), который после записи нашего кода принимает следующий вид.
Листинг 20.23. Метод-обработчик щелчка кнопки.
Private Sub Button1_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles Button1.Click
HighScores.ResetScores()
Me.DataGridView1.DataSource = HighScores.GetHighScores()
End Sub
В случае необходимости, методика добавления в проект звукового сигнала Beep (по-русски: Бип) описана ранее.
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