檢查圖片框圖像的索引

Question

我正在創建一個紙牌游戲，其中從圖像列表加載圖像並顯示一小段時間，然后“隱藏” - 卡片中的圖像發生變化。 當我單擊這些圖像中的任何一個時，我需要幫助，以便它告訴我卡片的索引，然后我可以更改該卡片中的圖像。 這將由下面發布的代碼中的最后一個 Sub 使用； “卡片用戶點擊”。

Public Class Form1
Private Cards As New List(Of PictureBox)
Private randomnumber As Integer
Private UserChoice As Integer
Private Timer As Integer

Private Sub SetupCards(numberofcards As Integer)
    ClearGame()
    For i As Integer = 0 To numberofcards
        Dim PicCard As PictureBox = New PictureBox()
        RandomCard()
        PicCard.Width = 100
        PicCard.Height = 200
        PicCard.Top = 50
        PicCard.Left = 50 + PicCard.Width * i
        Me.Controls.Add(PicCard)
        PicCard.Image = imglist1.Images(randomnumber)
        PicCard.Tag = randomnumber
        AddHandler PicCard.Click, AddressOf Me.cardflip_click
        Cards.Add(PicCard)
    Next i
End Sub

Private Sub ClearGame()
    If Cards.Count > 0 Then
        For i As Integer = 0 To Cards.Count - 1
            Me.Controls.Remove(Cards(i))
        Next
    End If
    ' Clear the cards if they were already setup from a previous game.
    Cards.Clear()
End Sub

Private Sub EndRound()
    'set all the images to back of card
    If Cards.Count > 0 Then
        For i As Integer = 0 To Cards.Count - 1
            Cards(i).Image = imglistBackOfCard.Images(2)
        Next
    End If

End Sub

Private Sub cardflip_click(sender As Object, e As EventArgs)
    Dim picture As PictureBox = CType(sender, PictureBox)
    Dim idTag As Integer = CType(picture.Tag, Integer)
    'MsgBox(idTag)
    UserChoice = idTag
End Sub

Private Sub btnstartGame_Click(sender As Object, e As EventArgs) Handles btnStartGame.Click
    Dim howmanycards As String
    howmanycards = InputBox("How Many Cards?", "Please Enter")
    SetupCards(Int(howmanycards - 1))
    ListBox1.Enabled = True
    ListBox1.Visible = True
    For Each imagesNames As String In imglist1.Images.Keys
        ListBox1.Items.Add(imagesNames)
    Next
    Timer1.Start()
End Sub

Private Sub ListBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ListBox1.SelectedIndexChanged
    If UserChoice = ListBox1.SelectedIndex Then
        MsgBox("correct")
        Cards(CARDTHEUSERCLICKED).Image = imglist1.Images(UserChoice)
        ' Cards(idTag).Image = 
    Else
        MsgBox("WRONG :(")
        Cards(CARDTHEUSERCLICKED).Image = imglist1.Images(UserChoice)
    End If
End Sub
End Class

Answer 1

您應該只存儲對圖片框本身的引用，而不是嘗試獲取被點擊卡片的索引。 添加另一個變量：

Private Cards As New List(Of PictureBox)
Private randomnumber As Integer
Private UserChoice As Integer
Private Timer As Integer
Private ClickedCard As PictureBox 'This is new.

然后在您的Click事件處理程序中，將ClickedCard的值設置為引發事件的圖片框（也就是事件的sender ）。

Private Sub cardflip_click(sender As Object, e As EventArgs)
    Dim picture As PictureBox = CType(sender, PictureBox)
    Dim idTag As Integer = CType(picture.Tag, Integer)

    UserChoice = idTag
    ClickedCard = picture
End Sub

最后，只需使用該參考而不是嘗試從您的列表中獲取它：

If ClickedCard Is Nothing Then 'Make sure that a card has been clicked, otherwise the below code will fail.
    MsgBox("You must select a card.")
    Return 'Do not continue execution of this code.
End If

If UserChoice = ListBox1.SelectedIndex Then
    MsgBox("correct")
    ClickedCard.Image = imglist1.Images(UserChoice)
Else
    MsgBox("WRONG :(")
    ClickedCard.Image = imglist1.Images(UserChoice)
End If

您還必須更新ClearGame()方法，以便將ClickedCard設置為 null：

Private Sub ClearGame()
    ...the rest of your code...

    ClickedCard = Nothing
End Sub