出于某种原因，当我关闭包含它们的表单时，powerpack矩形形状会抛出Collection was modified; enumeration operation may not execute.错误。任何线索为什么会这样？这是例外文本。有什么线索有什么不对？如果我删除矩形，错误会自行解决，但我宁愿不这样做。谢谢！
See the end of this message for details on invoking
just-in-time (JIT) debugging instead of this dialog box.
************** Exception Text **************
System.InvalidOperationException: Collection was modified; enumeration operation may not execute.
at System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource resource)
at System.Collections.Generic.List`1.Enumerator.MoveNextRare()
at System.Collections.Generic.List`1.Enumerator.MoveNext()
at Microsoft.VisualBasic.PowerPacks.ShapeCollection.Dispose(Boolean disposing)
at Microsoft.VisualBasic.PowerPacks.ShapeContainer.Dispose(Boolean disposing)
at System.ComponentModel.Component.Dispose()
at System.Windows.Forms.Control.Dispose(Boolean disposing)
at System.Windows.Forms.Form.Dispose(Boolean disposing)
at POS_System.DatabaseManager.Dispose(Boolean disposing) in c:\Users\user\Desktop\Co-op\Co-op\C#\POS System\POS System\POS System\DatabaseManager.Designer.cs:line 20
at System.ComponentModel.Component.Dispose()
at System.Windows.Forms.Form.WmClose(Message& m)
at System.Windows.Forms.Form.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.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
************** Loaded Assemblies **************
mscorlib
Assembly Version: 4.0.0.0
Win32 Version: 4.0.30319.18408 built by: FX451RTMGREL
CodeBase: file:///C:/Windows/Microsoft.NET/Framework/v4.0.30319/mscorlib.dll
----------------------------------------
Point Of Sales
Assembly Version: 1.0.0.0
Win32 Version: 1.0.0.0
CodeBase: file:///C:/Users/user/Desktop/Co-op/Co-op/C%23/POS%20System/POS%20System/POS%20System/bin/Debug/Point%20Of%20Sales.exe
----------------------------------------
System.Windows.Forms
Assembly Version: 4.0.0.0
Win32 Version: 4.0.30319.18408 built by: FX451RTMGREL
CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Windows.Forms/v4.0_4.0.0.0__b77a5c561934e089/System.Windows.Forms.dll
----------------------------------------
System.Drawing
Assembly Version: 4.0.0.0
Win32 Version: 4.0.30319.18408 built by: FX451RTMGREL
CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Drawing/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Drawing.dll
----------------------------------------
System
Assembly Version: 4.0.0.0
Win32 Version: 4.0.30319.18408 built by: FX451RTMGREL
CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System/v4.0_4.0.0.0__b77a5c561934e089/System.dll
----------------------------------------
System.Configuration
Assembly Version: 4.0.0.0
Win32 Version: 4.0.30319.18408 built by: FX451RTMGREL
CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Configuration/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Configuration.dll
----------------------------------------
System.Xml
Assembly Version: 4.0.0.0
Win32 Version: 4.0.30319.18408 built by: FX451RTMGREL
CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Xml/v4.0_4.0.0.0__b77a5c561934e089/System.Xml.dll
----------------------------------------
Microsoft.VisualBasic.PowerPacks.Vs
Assembly Version: 10.0.0.0
Win32 Version: 10.0.20911.1
CodeBase: file:///C:/Windows/assembly/GAC_MSIL/Microsoft.VisualBasic.PowerPacks.Vs/10.0.0.0__b03f5f7f11d50a3a/Microsoft.VisualBasic.PowerPacks.Vs.dll
----------------------------------------
Microsoft.VisualBasic
Assembly Version: 10.0.0.0
Win32 Version: 11.0.50938.18408 built by: FX451RTMGREL
CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/Microsoft.VisualBasic/v4.0_10.0.0.0__b03f5f7f11d50a3a/Microsoft.VisualBasic.dll
----------------------------------------
System.Core
Assembly Version: 4.0.0.0
Win32 Version: 4.0.30319.18408 built by: FX451RTMGREL
CodeBase: file:///C:/Windows/Microsoft.Net/assembly/GAC_MSIL/System.Core/v4.0_4.0.0.0__b77a5c561934e089/System.Core.dll
----------------------------------------
************** JIT Debugging **************
To enable just-in-time (JIT) debugging, the .config file for this
application or computer (machine.config) must have the
jitDebugging value set in the system.windows.forms section.
The application must also be compiled with debugging
enabled.
For example:
<configuration>
<system.windows.forms jitDebugging="true" />
</configuration>
When JIT debugging is enabled, any unhandled exception
will be sent to the JIT debugger registered on the computer
rather than be handled by this dialog box.