vb.net - 用户界面消失并出现错误 : out of memory

Question

我有一个问题，即离开程序一段时间后，假设 5 分钟或更长时间，用户界面开始消失，例如:按钮、标签...等

然后，如果我尝试单击任何内容，它会显示如下错误:内存不足

我使用的自定义控件是:Bunifu_UI_v1.5.3

但我使用简单的东西，如 datagridview 和 datetimepicker

但我不认为这有问题，因为我使用的几乎所有东西都是原始 Visual Studio 的原始控件。

有很多这样的代码:

Private Sub close_butt_MouseEnter(sender As Object, e As EventArgs) Handles close_butt.MouseEnter
    close_butt.Image = My.Resources.Close_white_32
    close_butt.BackColor = Color.Red
End Sub
Private Sub close_butt_MouseLeave(sender As Object, e As EventArgs) Handles close_butt.MouseLeave
    close_butt.Image = My.Resources.Close_white_32
    close_butt.BackColor = Nothing
End Sub

这是错误:

这是完整的错误文本:

System.OutOfMemoryException was unhandled
HResult=-2147024882
Message=Out of memory.
StackTrace:
   at System.Drawing.Graphics.FromHdcInternal(IntPtr hdc)
   at System.Windows.Forms.ComboBox.WmReflectDrawItem(Message& m)
   at System.Windows.Forms.ComboBox.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
   at System.Windows.Forms.UnsafeNativeMethods.SendMessage(HandleRef hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)
   at System.Windows.Forms.Control.SendMessage(Int32 msg, IntPtr wparam, IntPtr lparam)
   at System.Windows.Forms.Control.ReflectMessageInternal(IntPtr hWnd, Message& m)
   at System.Windows.Forms.Control.WmOwnerDraw(Message& m)
   at System.Windows.Forms.Control.WmDrawItem(Message& m)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
   at System.Windows.Forms.UnsafeNativeMethods.CallWindowProc(IntPtr wndProc, IntPtr hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)
   at System.Windows.Forms.NativeWindow.DefWndProc(Message& m)
   at System.Windows.Forms.Control.DefWndProc(Message& m)
   at System.Windows.Forms.Control.WmSetFocus(Message& m)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ComboBox.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
   InnerException: 

Answer 1

至少有一个问题出现在这样的代码中(而且很多):

Private Sub stores_but_MouseEnter(sender As Object, e As EventArgs) Handles stores_but.MouseEnter
    stores_but.Image = My.Resources.Stores_1
    Stores_Panel.Visible = True
End Sub
Private Sub stores_but_MouseLeave(sender As Object, e As EventArgs) Handles stores_but.MouseLeave
    stores_but.Image = My.Resources.Stores
    Stores_Panel.Visible = False
End Sub

My.Resources 不是任何内容的集合，包括图像或位图。如果您深入研究这些内容，您将看到如下代码:

Friend ReadOnly Property Stores() As System.Drawing.Bitmap
    Get
        Dim obj As Object = ResourceManager.GetObject("Stores", resourceCulture)
        Return CType(obj,System.Drawing.Bitmap)
    End Get
End Property

它正在从其他地方存储的数据创建一个新的 Bitmap 对象。但是位图是一种资源，在使用完毕后必须将其释放，而 Enter/Leave 代码不会执行此操作。

在 series of repeating images 的情况下情况可能会更糟例如状态或一组是/否图像:您不需要 10 或 20 个唯一图像，但这是从 My.Resources 获取每张图像的结果。直接使用 Myresources 中的图像更新状态的计时器可能很快就会耗尽句柄。

要解决这个问题，请将图像加载到数组或列表中并使用它们:

Private StatusImgs As Image()

在表单加载的其他地方可能:

StatusImgs = New Image() {
                        My.Resources.ballblack, My.Resources.ballblue,
                        My.Resources.ballgreen,
                        My.Resources.ballorange, My.Resources.ballpurple,
                        My.Resources.ballred, My.Resources.ballyellow
                        }

用法:

myBtn.Image = StatusImgs(0)

现在，我的整个表单中将总共使用一 (1) 个绿球图像。您可以使用枚举使代码更具可读性:

Private Enum Status
    Away 
    Busy 
    IgnoringYou
    Dead
    ...
End Enum

myBtn.Image = StatusImgs(Status.Busy)