Keep Graphics On Me.Refresh()

Question

我正在为一个类项目创建一个Visual Basic的刽子手游戏，并且我创建了一个函数，当您在单词中的适当位置猜测正确的字母时，该函数会绘制一个字符串。我的问题是，每当我进行新的猜测时，它都会删除旧图形并添加新图形。我需要一种方法来保存我绘制的图形，有人知道吗？

Dim newCharArray() As Char = wordArray(rndNumber).ToCharArray
For i As Integer = 0 To (wordArray(rndNumber).Length - 1) Step 1
    If TextBox1.Text = newCharArray(i) Then
        correctLetter = newCharArray(i)
        letterPos = i
        Me.Refresh()
    End If
Next
Dim drawFont As New Font("Microsoft YaHei UI", 16)
Dim drawBrush As New SolidBrush(Color.Black)
Dim drawString As [String] = CStr(correctLetter)
Dim drawPoint As New PointF(x:=(x1 + 4) + (letterPos * 40), y:=363)
e.Graphics.DrawString(drawString, drawFont, drawBrush, drawPoint)

Answer 1

问题是Paint方法每次都负责从头开始绘制整个内容。

我会维护所有正确字符及其位置的列表，并在每次Paint方法中绘制它们。

或者，您可以将每个字符绘制到一个Bitmap，然后在 Paint 方法中绘制位图，如下所示：

Private canvas As Bitmap = New Bitmap(Me.ClientRectangle.Width, Me.ClientRectangle.Height)
...
    Dim newCharArray() As Char = wordArray(rndNumber).ToCharArray
    For i As Integer = 0 To (wordArray(rndNumber).Length - 1) Step 1
        If TextBox1.Text = newCharArray(i) Then
            correctLetter = newCharArray(i)
            letterPos = i
            Me.Refresh()
        End If
    Next
...
Private Sub Form1_Paint(sender As Object, e As System.Windows.Forms.PaintEventArgs) Handles Me.Paint
    Dim drawFont As New Font("Microsoft YaHei UI", 16)
    Dim drawBrush As New SolidBrush(Color.Black)
    Dim drawString As [String] = CStr(correctLetter)
    Dim drawPoint As New PointF(x:=(x1 + 4) + (letterPos * 40), y:=363)
    Using g As Graphics = Graphics.FromImage(Me.canvas)
        g.DrawString(drawString, drawFont, drawBrush, drawPoint)
    End Using
    e.Graphics.DrawImage(Me.canvas, New Point(0, 0))
End Sub