在 flowlayoutpanel 重用控件

Question

我有 3 个按钮：1ºbtn 将 3 个图片框添加到 flowlayoutpanel 中。 2ºbtn 尝试从流程面板中删除控件 3ºbtn 仅将 2 个图片框添加到 flowlayoupanel

我使用（循环）将名为 picturebox1、picturebox2 的图片框添加到流程面板中的代码是这样的：

For i As Integer = 1 To 3
        If Me.Controls.ContainsKey("PictureBox" & i) Then
            Me.Controls("PictureBox" & i).Visible = True
            Me.Controls("PictureBox" & i).Margin = New Padding(0)
            Dim px As PictureBox = CType(Me.Controls("PictureBox" & i), PictureBox)
            FlowLayoutPanel1.Controls.Add(px)
End If
next

我试过的删除代码是这些：

FlowLayoutPanel1.Controls.clear()

我也试过：

While
(FlowLayoutPanel1.Controls.Count > )FlowLayoutPanel1.Controls.RemoveAt(0)
End While

还有：

For i As Integer = 1 to 3
If Me.Controls.ContainsKey("PictureBox" & i) Then
Me.Controls("PictureBox" & i).remove()
Me.Controls("PictureBox" & i).Visible = False

我也试过：

For i As Integer = 1 to 3
If Me.Controls.ContainsKey("PictureBox" & i) Then
Me.Controls("PictureBox" & i).Dispose()

所有要删除的代码都可以正常工作，但是我无法再次将相同的图片框再次添加到任何流程面板中...

Answer 1

当您从容器中删除控件时，需要在失去其引用之前将其添加回另一个容器。请记住，任何未被任何对象引用的对象最终都会被 GC 收集（删除）。所以当你调用 Remove() 或 Clear() 时，立即将其添加回主窗体或本地窗体级集合，以便它保留在内存中。

Answer 2

如 dotNET 所述，您需要维护对对象的引用。

示例：--

//To store existing picture boxes- 

Dim MyObjects as new list(of Picturebox)

Private sub RemoveObJect(Obj as pictureBox)
   //remove the object from flowlayoutpanel
   FlowLayoutPanel1.Controls.remove(Obj)
   //Add the object to a collection - I would wrap the object into a custom
   //Class to hold more information about it 
   MyObjects.add(Obj)
End Sub

Private sub RestoreObJect(Obj as pictureBox)
   //reverse the remove procedure
   FlowLayoutPanel1.Controls.add(Obj) //or add to a specific index
   MyObjects.remove(Obj)
End Sub






Private Sub RemoveObject(Obj as button) ...

在 flowlayoutpanel 重用控件

reuse controls at flowlayoutpanel

vb.net

for-loop

picturebox

flowlayoutpanel