对于现在的几个项目，我已经出现了这个错误并完全启动了我的项目。在大多数情况下，我只需要离开它们并开始一个新的，不同的。基本上，我只是希望能够引用符合特定条件的表单上的每个对象。在这种情况下，它是一款具有四种不同游戏模式的街机风格游戏。有一个计时器可以创建要拍摄的对象，它可以正常工作，可以是PictureBox，也可以是标签，具体取决于哪种模式。在创建时，它将每个对象的标记更改为“Obj”＆amp; 任何形状/数学数字，中间有空格。但由于某种原因，它不会在不同的计时器刻度事件上创建一系列排序来移动它们。
我只需要它能够不断添加和删除要拍摄的对象，添加和移动和删除工作正常，但在我所有其他情况下使用数组这个错误只是蠕动它和我和我认真合格的IPT老师无法弄明白。它为什么突然开始这样做，我该如何解决？附件是对象移动事件的一些代码。
Dim NumofObjsLeft As Integer = 0
For Each obj As Object In Me.Controls
If obj.Tag.Contains("Obj") Then
NumofObjsLeft += 1
If NumofObjsLeft <= 0 Then
Wav += 1
WaveStart = True
End If
Select Case GameMode
Case "Protector"
Select Case Curry
Case "Shapes"
If TypeOf obj Is PictureBox AndAlso obj.Tag.Contains("Obj") Then
obj.Left += 15
End If
Case "Maths"
If TypeOf obj Is Label AndAlso obj.tag.Contains("Obj") Then
obj.Left += 15
End If
End Select
编辑：我想我会为Shape Spawn和Move添加所有代码。我还没有完成Shape Move的另一半代码，因为我无法让第一部分工作。
Private Sub tmrShapeSpawn_Tick(sender As System.Object, e As System.EventArgs) Handles tmrShapeSpawn.Tick
If WaveStart = True Then
Select Case Wav
Case 1
NumofObjs = Wave1
Case 2
NumofObjs = Wave2
Case 3
NumofObjs = Wave3
Case 4
NumofObjs = Wave4
Case 5
NumofObjs = Wave5
Case 6
NumofObjs = Wave6
End Select
If F < NumofObjs Then
Dim newPic As PictureBox = New PictureBox
Dim newLab As Label = New Label
Dim CorrectLabel As Label = New Label
Dim CorrectPictureBox As PictureBox = New PictureBox
CorrectPictureBox.Height = 75
CorrectPictureBox.Width = 100
CorrectLabel.AutoSize = True
CorrectLabel.BackColor = Color.Transparent
CorrectPictureBox.BackColor = Color.Transparent
CorrectPictureBox.SizeMode = PictureBoxSizeMode.Zoom
CorrectLabel.ForeColor = Color.Blue
CorrectLabel.Font = New Font("Goudy Stout", 60, FontStyle.Regular)
Select Case GameMode
Case "Protector"
Randomize()
If CorrectMade = False Then
CorrectLabel.Left = CorrectLabel.Width
CorrectPictureBox.Left = CorrectPictureBox.Width
CorrectLabel.Top = Int(Rnd() * (Me.Height - CorrectLabel.Height))
CorrectPictureBox.Top = Int(Rnd() * (Me.Height - CorrectPictureBox.Height))
End If
newLab.Left = newLab.Width
newPic.Left = newPic.Width
newLab.Top = Int(Rnd() * (Me.Height - newLab.Height))
newPic.Top = Int(Rnd() * (Me.Height - newPic.Height))
Case "Catcher"
Randomize()
If CorrectMade = False Then
CorrectLabel.Top = CorrectLabel.Height
CorrectPictureBox.Top = CorrectPictureBox.Height
CorrectLabel.Left = Int(Rnd() * (Me.Width - CorrectLabel.Width))
CorrectPictureBox.Left = Int(Rnd() * (Me.Width - CorrectPictureBox.Width))
End If
newLab.Top = newLab.Height
newPic.Top = newPic.Height
newLab.Left = Int(Rnd() * (Me.Width - newLab.Width))
newPic.Left = Int(Rnd() * (Me.Width - newPic.Width))
End Select
Select Case Curry
Case "Maths"
lblCriteria.Text = lstNum1.Items.Item(Wav - 1) & " " & lstOp.Items.Item(Wav - 1) & " " & lstNum2.Items.Item(Wav - 1) & " ="
If CorrectMade = False Then
CorrectLabel.Text = lstAns.Items.Item(Wav - 1)
CorrectLabel.Tag = "Obj " & lstAns.Items.Item(Wav - 1)
Me.Controls.Add(CorrectLabel)
CorrectLabel.BringToFront()
End If
Randomize()
newLab.Text = Int(Rnd() * 100)
newLab.Tag = "Obj " & newLab.Text
Me.Controls.Add(CorrectLabel)
CorrectLabel.BringToFront()
Case "Shapes"
Dim epahs As Integer
Dim sap As String
lblCriteria.Text = lstShape.Items.Item(Wav - 1)
If CorrectMade = False Then
CorrectPictureBox.ImageLocation = "Shapes\" & lstShape.Items.Item(Wav - 1) & ".png"
CorrectPictureBox.Tag = "Obj " & lstShape.Items.Item(Wav - 1)
Me.Controls.Add(CorrectPictureBox)
CorrectPictureBox.BringToFront()
End If
Randomize()
epahs = Int(Rnd() * 9)
Select Case epahs
Case 0
sap = "Square"
Case 1
sap = "Circle"
Case 2
sap = "Triangle"
Case 3
sap = "Rectangle"
Case 4
sap = "Oval"
Case 5
sap = "Hexagon"
Case 6
sap = "Star"
Case 7
sap = "Diamond"
Case 8
sap = "Trapezium"
Case 9
sap = "Rhombus"
End Select
newPic.ImageLocation = "Shapes\" & sap & ".png"
newPic.Tag = "Obj " & sap
newPic.SizeMode = PictureBoxSizeMode.Zoom
Me.Controls.Add(newPic)
newPic.BringToFront()
End Select
CorrectMade = True
F += 1
Else
WaveStart = False
End If
End If
End Sub
Private Sub tmrShapeMove_Tick(sender As System.Object, e As System.EventArgs) Handles tmrShapeMove.Tick
Dim CBA As Integer
Dim NumofObjsLeft As Integer = 0
For Each obj As Object In Me.Controls
If obj.Tag.Contains("Obj") Then
NumofObjsLeft += 1
If NumofObjsLeft <= 0 Then
Wav += 1
WaveStart = True
End If
Select Case GameMode
Case "Protector"
Select Case Curry
Case "Shapes"
If TypeOf obj Is PictureBox AndAlso obj.Tag.Contains("Obj") Then
obj.Left += 15
End If
Case "Maths"
If TypeOf obj Is Label AndAlso obj.tag.Contains("Obj") Then
obj.Left += 15
End If
End Select
For CBA = 0 To ABC Step 1
If Collision(obj, Missile(CBA)) Then
Missile(CBA).Visible = False
Missile(CBA).Enabled = False
If picExplosion1.Visible = True And picExplosion2.Visible = False And picExplosion3.Visible = False Then
picExplosion2.Visible = True
tmrExplosion2.Start()
CentreOn(obj, picExplosion2)
ElseIf picExplosion1.Visible = True And picExplosion2.Visible = True And picExplosion3.Visible = False Then
picExplosion3.Visible = True
tmrExplosion3.Start()
CentreOn(obj, picExplosion3)
ElseIf picExplosion1.Visible = False Then
picExplosion1.Visible = True
tmrExplosion1.Start()
CentreOn(obj, picExplosion1)
Else
End If
If obj.Tag.Contains(lblCriteria.Text) Then
lblScore.Text += 1
Else
lblLives.Text -= 1
End If
Me.Controls.Remove(obj)
End If
Next CBA
Case "Catcher"
Select Case Curry
Case "Shapes"
If TypeOf obj Is PictureBox AndAlso obj.Tag.Contains("Obj") Then
obj.Top += 15
End If
Case "Maths"
If TypeOf obj Is Label AndAlso obj.Tag.Contains("Obj") Then
obj.Top += 15
End If
End Select
If Collision(obj, picChar) Then
If obj.Tag.Contains(lblCriteria.Text) Then
Score += 1
Else
Lives -= 1
End If
Me.Controls.Remove(obj)
End If
End Select
End If
Next obj
End Sub
答案 0 :(得分：4)
1）使用background worker代替计时器。它构建为与主表单线程正确交互并更清晰地处理控件交互。对于主要的UI线程同步问题和意外退出，计时器都是出了问题。
2）你必须处理obj.Tag或obj什么都不是。最简单的方法是添加
If obj is Nothing OrElse String.IsNullOrWhitespace(obj.Tag) Then
Continue For
End If
...作为For循环后的第一个语句。
答案 1 :(得分：0)
对，感谢所有评论的人，回答说。它现在似乎只是在那个额外的条件下工作。添加if语句以在比较文本之前检查标记是否为空。
Dim NumofObjsLeft As Integer = 0
For Each obj As Object In Me.Controls
If obj.Tag > "" Then
If obj.Tag.Contains("Obj") Then
NumofObjsLeft += 1
If NumofObjsLeft <= 0 Then
Wav += 1
WaveStart = True
End If
Select Case GameMode
Case "Protector"
Select Case Curry
ETC...................................................