我为我的A-Level计算项目制作坦克游戏（物理模拟器）。几个星期以来，一切都很顺利，从大约一周前我就得到了一个参数无效＆＃34;将X和Y值传递给创建新位图时。
这是引发错误的行：
backbuffer = New Bitmap(clientWidth, clientHeight) 'sets the area for the objects to exist in`
到目前为止，这是完整的代码：
Imports System.Threading
Imports System.Drawing
Public Class Form1
Dim boostart As Boolean
Dim locationX As Double = 10
Dim locationy As Double = 550
Dim circle As [Rectangle]
Dim Player1 As [Rectangle]
Dim P1Xlocation As Double = 10
Dim P1Ylocation As Double = 550
Dim ballOut As Boolean
Dim backbuffer As Bitmap
Dim graphics As Graphics
Dim clientWidth As Integer = 1500
Dim clientHeight As Integer = 600
Dim uHorizontal As Double
Dim uVertical As Double
Dim intAngle As Double
Dim intPower As Integer
Dim gameClock As Stopwatch
Dim interval As Integer
Dim starttick As Long
Dim t As Double = 0
Public Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Me.KeyPreview = True 'allows for background key presses.
gameClock = New Stopwatch
interval = 6
Player1 = New Rectangle(P1Xlocation, P1Ylocation, 30, 550) 'displays the player on load
circle = New Rectangle(Player1.Right, Player1.Top, 10, 550)
gameloop()
End Sub
Public Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick 'timer for moving the projectile
If boostart = True Then
If Not ballOut = True Then 'if the ball isnt going to moveout of bounds, move the ball
moveBall(intAngle, intPower)
End If
End If
End Sub
Public Sub gameloop()
gameClock.Start()
Do While (Me.Created) 'infinite loop for the game
starttick = gameClock.ElapsedMilliseconds
render() 'renders the scene
collisions() 'checks for collisions
Application.DoEvents()
Do While gameClock.ElapsedMilliseconds - starttick < interval 'to keep the game clock stable to make the game more smooth
Loop
Loop
End Sub
Public Sub moveBall(theta, mag) 'sub-routine for moving the projectile
theta = theta * (Math.PI / 180)
Dim uHorizontal As Double = mag * Math.Cos(theta)
Dim uVertical As Double = mag * Math.Sin(theta)
If 550 - ((uVertical * t) + (0.5 * (-9.81) * t ^ 2)) > clientHeight Then 'validation to see if the next pass through will
Timer1.Stop() 'move the projecile out of bounds.
MsgBox("Ball will go out of bounds")
ballOut = True
Else locationy = 550 - ((uVertical * t) + (0.5 * (-9.81) * t ^ 2)) 'updates the Y value of the ball using the formulae
End If '(1/2(-9.81)t^2)
If (uHorizontal * t) > clientWidth Then
Timer1.Stop()
MsgBox("Ball will go out of bounds")
ballOut = True
Else locationX = (uHorizontal * t) 'Updates X value using the formulae (u*t)
End If
Me.Refresh()
t += 0.05 'increases t
Debug.Print("YUvertical = " & uVertical)
Debug.Print("UHorizontal = " & uHorizontal)
Debug.Print("Theta =" & theta)
Debug.Print("X:" & locationX)
Debug.Print("Y:" & locationy)
'Threading.Thread.Sleep(1000)
gameloop()
End Sub
Public Sub collisions() 'basic collision detection with borders of the play area
If circle.X > clientWidth Then
MsgBox("collision")
End If
If circle.Y > clientHeight Then
MsgBox("collision")
End If
End Sub
Public Sub MoveP1(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles MyBase.KeyDown
Select Case e.KeyCode 'for moving the players characcter
Case Keys.W
Case Keys.S
Case Keys.A
Player1.X += -10
Case Keys.D
Player1.X += 10
End Select
End Sub
Public Sub render()
backbuffer = New Bitmap(clientWidth, clientHeight) 'sets the area for the objects to exist in
graphics = Graphics.FromImage(backbuffer) 'allows to draw on the background
PbSurface.Image = Nothing 'makes picturebox nothing
graphics.FillRectangle(Brushes.Green, Player1) 'defines the players square
graphics.FillEllipse(Brushes.Red, circle) 'defines the projectile
PbSurface.Image = backbuffer 'sets the picturebox to the new bitmap
Player1 = New Rectangle(P1Xlocation, P1Ylocation, 30, 30) 'Updates object positions on screen
circle = New Rectangle(Player1.Right, Player1.Top, 10, 10)
End Sub
Public Sub BtnFire_Click(sender As Object, e As EventArgs) Handles BtnFire.Click
boostart = True 'sets timer off to move the fired projectile
If IsNumeric(TxtAngle.Text) And IsNumeric(txtPower.Text) _
And IsNumeric(TxtTime.Text) And IsNumeric(TxtVelocity.Text) Then 'validation for invalid inputs
t = TxtTime.Text
uVertical = TxtVelocity.Text
intAngle = TxtAngle.Text
intPower = txtPower.Text
Else : MsgBox("Please check your inputs, the simulator doesnt accept letters Or words.")
End If
End Sub
End Class
还有一些表单控件，包括PictureBox（pbSurface），4个TextBoxes和一个Button。