C# System.InvalidOperationException：集合已修改；枚举操作可能无法执行

Question

我研究过这个问题，但还没有找到适合我的问题。我不想编辑我正在循环浏览的内容。

************** 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()

这是导致它的函数：

internal static bool CloseAllForms()
{
    try
    {
        if (clsGlobal.g_objfrmCustomerInformation != null)
            clsGlobal.g_objfrmCustomerInformation.Close();
        if (clsGlobal.g_objfrmSearchCustomer != null)
            clsGlobal.g_objfrmSearchCustomer.Close();

        if (clsGlobal.g_objfrmSwipeLicense != null)
            clsGlobal.g_objfrmSwipeLicense.Close();

        if (clsGlobal.g_objfrmSearchResults != null)
            clsGlobal.g_objfrmSearchResults.Close();

        if (clsGlobal.g_objfrmCustomerData != null)
            clsGlobal.g_objfrmCustomerData.Close();
        if (clsGlobal.g_objfrmPurchaseOrder != null)
            clsGlobal.g_objfrmPurchaseOrder.Close();
        if (clsGlobal.g_objfrmAddPurchaseOrderItem != null)
            clsGlobal.g_objfrmAddPurchaseOrderItem.Close();
        if ((clsGlobal.g_objfrmCustomerInformation == null) && (clsGlobal.g_objfrmSearchCustomer == null) && (clsGlobal.g_objfrmSwipeLicense == null) && (clsGlobal.g_objfrmSearchResults == null) && (clsGlobal.g_objfrmCustomerData == null) && (clsGlobal.g_objfrmPurchaseOrder == null) && (clsGlobal.g_objfrmAddPurchaseOrderItem == null))
        {
            PrepareImageBar();
            return true;
        }
        else
        {
            PrepareImageBar();
            return false;
        }
    }
    catch (Exception ex)
    {
        string ErrorMessage;

        ErrorMessage = "Error: " + ex.Message +
           "\r\nSource: " + ex.Source +
           "\r\nTargetSite: " + ex.TargetSite.ToString() +
           "\r\nStackTrace: " + ex.StackTrace.ToString();

        if (ex.Data.Count > 0)
        {
            ErrorMessage += "\r\nData Count: " + ex.Data.Count.ToString() +
                "\r\nKeys: " + ex.Data.Keys.ToString() +
                "\r\nValues: " + ex.Data.Values.ToString();
        }

        MessageBox.Show(ErrorMessage, "", MessageBoxButtons.OK, MessageBoxIcon.Error);
        CustomFunctions.emailExceptionToAuthor(ex);

        return false;
    }
}

这就是我调用该函数的方式：

if (CloseAllForms())
{
    if (clsGlobal.g_objfrmPurchaseOrder == null)
    {
        clsGlobal.g_objfrmPurchaseOrder = new frmPurchaseOrder();

        clsGlobal.g_objfrmPurchaseOrder.FormClosed += PurchaseOrderFormClosed;
        clsGlobal.g_objfrmPurchaseOrder.MdiParent = clsGlobal.g_objfrmMDIMain;
        clsGlobal.g_objfrmPurchaseOrder.Show();
        clsGlobal.g_objfrmPurchaseOrder.BringToFront();
    }
    else
    {
        clsGlobal.g_objfrmPurchaseOrder.Show();
        clsGlobal.g_objfrmPurchaseOrder.BringToFront();
    }

    PrepareImageBar();
}

请帮助我！

更新：这是完整的代码。

例外情况 有关调用的详细信息，请参阅此消息的末尾 即时 (JIT) 调试而不是此对话框。

************** 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 B2HD_Software.frmCustomerData.Dispose(Boolean disposing)
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)

准备ImageBar();

internal static void PrepareImageBar()
{
clsGlobal.g_objfrmMDIMain.mnuImageBarAddCustomer.Visible = false;
clsGlobal.g_objfrmMDIMain.mnuImageBarAddCustomer.Enabled = true;
clsGlobal.g_objfrmMDIMain.mnuImageBarEditCustomer.Visible = false;
clsGlobal.g_objfrmMDIMain.mnuImageBarEditCustomer.Enabled = true;
clsGlobal.g_objfrmMDIMain.mnuImageBarFindCustomer.Visible = false;
clsGlobal.g_objfrmMDIMain.mnuImageBarFindCustomer.Enabled = true;
clsGlobal.g_objfrmMDIMain.mnuImageBarStartSearch.Visible = false;
clsGlobal.g_objfrmMDIMain.mnuImageBarStartSearch.Enabled = false;
clsGlobal.g_objfrmMDIMain.mnuImageBarSwipeLicense.Visible = false;
clsGlobal.g_objfrmMDIMain.mnuImageBarSwipeLicense.Enabled = true;
clsGlobal.g_objfrmMDIMain.mnuImageBarViewNotes.Visible = false;
clsGlobal.g_objfrmMDIMain.mnuImageBarViewNotes.Enabled = true;
clsGlobal.g_objfrmMDIMain.mnuImageBarNewPurchase.Visible = false;
clsGlobal.g_objfrmMDIMain.mnuImageBarNewPurchase.Enabled = true;
clsGlobal.g_objfrmMDIMain.mnuImageBarAddItem.Visible = false;
clsGlobal.g_objfrmMDIMain.mnuImageBarAddItem.Enabled = true;
clsGlobal.g_objfrmMDIMain.mnuImageBarModifyItem.Visible = false;
clsGlobal.g_objfrmMDIMain.mnuImageBarModifyItem.Enabled = false;
clsGlobal.g_objfrmMDIMain.mnuImageBarDeleteItem.Visible = false;
clsGlobal.g_objfrmMDIMain.mnuImageBarDeleteItem.Enabled = false;
clsGlobal.g_objfrmMDIMain.mnuImageBarTakePicture.Visible = false;
clsGlobal.g_objfrmMDIMain.mnuImageBarTakePicture.Enabled = true;
clsGlobal.g_objfrmMDIMain.mnuImageBarSavePicture.Visible = false;
clsGlobal.g_objfrmMDIMain.mnuImageBarSavePicture.Enabled = true;
clsGlobal.g_objfrmMDIMain.mnuImageBarSave.Visible = false;
clsGlobal.g_objfrmMDIMain.mnuImageBarSave.Enabled = true;
clsGlobal.g_objfrmMDIMain.mnuImageBarCancel.Visible = false;
clsGlobal.g_objfrmMDIMain.mnuImageBarCancel.Enabled = true;
clsGlobal.g_objfrmMDIMain.mnuImageBarAdmin.Visible = false;
clsGlobal.g_objfrmMDIMain.mnuImageBarAdmin.Enabled = true;

switch (clsGlobal.ActiveForm())
{
    case "CustomerInformation":
        clsGlobal.g_objfrmMDIMain.mnuImageBarTakePicture.Visible = true;
        clsGlobal.g_objfrmMDIMain.mnuImageBarSave.Visible = true;
        clsGlobal.g_objfrmMDIMain.mnuImageBarCancel.Visible = true;
        clsGlobal.g_objfrmMDIMain.mnuImageBarCancel.Enabled = true;

        break;
    case "SearchCustomer":
        clsGlobal.g_objfrmMDIMain.mnuImageBarStartSearch.Visible = true;
        clsGlobal.g_objfrmMDIMain.mnuImageBarSwipeLicense.Visible = true;
        clsGlobal.g_objfrmMDIMain.mnuImageBarCancel.Visible = true;
        clsGlobal.g_objfrmMDIMain.mnuImageBarStartSearch.Enabled = false;

        break;
    case "SwipeLicense":
        clsGlobal.g_objfrmMDIMain.mnuImageBarCancel.Visible = true;

        break;
    case "CustomerData":
        clsGlobal.g_objfrmMDIMain.mnuImageBarCancel.Visible = true;
        clsGlobal.g_objfrmMDIMain.mnuImageBarViewNotes.Visible = true;
        clsGlobal.g_objfrmMDIMain.mnuImageBarNewPurchase.Visible = true;
        clsGlobal.g_objfrmMDIMain.mnuImageBarEditCustomer.Visible = true;

        break;
    case "PurchaseOrder":
        clsGlobal.g_objfrmMDIMain.mnuImageBarCancel.Visible = true;
        clsGlobal.g_objfrmMDIMain.mnuImageBarAddItem.Visible = true;
        clsGlobal.g_objfrmMDIMain.mnuImageBarDeleteItem.Visible = true;
        clsGlobal.g_objfrmMDIMain.mnuImageBarModifyItem.Visible = true;
        clsGlobal.g_objfrmMDIMain.mnuImageBarEditCustomer.Visible = true;
        clsGlobal.g_objfrmMDIMain.mnuImageBarViewNotes.Visible = true;

        clsGlobal.g_objfrmPurchaseOrder.ShowProperButtons();

        break;
    case "AddPurchaseOrderItem":
        clsGlobal.g_objfrmMDIMain.mnuImageBarTakePicture.Visible = true;
        clsGlobal.g_objfrmMDIMain.mnuImageBarSave.Visible = true;
        clsGlobal.g_objfrmMDIMain.mnuImageBarCancel.Visible = true;
        clsGlobal.g_objfrmMDIMain.mnuImageBarViewNotes.Visible = true;

        break;

    default:
        clsGlobal.g_objfrmMDIMain.mnuImageBarAddCustomer.Visible = true;
        clsGlobal.g_objfrmMDIMain.mnuImageBarFindCustomer.Visible = true;
        clsGlobal.g_objfrmMDIMain.mnuImageBarSwipeLicense.Visible = true;

        break;
}
}

CloseAllForms()

internal static bool CloseAllForms()
{
if (clsGlobal.g_objfrmCustomerInformation != null)
    clsGlobal.g_objfrmCustomerInformation.Close();

if (clsGlobal.g_objfrmSearchCustomer != null)
    clsGlobal.g_objfrmSearchCustomer.Close();

if (clsGlobal.g_objfrmSwipeLicense != null)
    clsGlobal.g_objfrmSwipeLicense.Close();

if (clsGlobal.g_objfrmSearchResults != null)
    clsGlobal.g_objfrmSearchResults.Close();

if (clsGlobal.g_objfrmCustomerData != null)
    clsGlobal.g_objfrmCustomerData.Close();

if (clsGlobal.g_objfrmPurchaseOrder != null)
    clsGlobal.g_objfrmPurchaseOrder.Close();

if (clsGlobal.g_objfrmAddPurchaseOrderItem != null)
    clsGlobal.g_objfrmAddPurchaseOrderItem.Close();

if ((clsGlobal.g_objfrmCustomerInformation == null) && (clsGlobal.g_objfrmSearchCustomer == null) && (clsGlobal.g_objfrmSwipeLicense == null) && (clsGlobal.g_objfrmSearchResults == null) && (clsGlobal.g_objfrmCustomerData == null) && (clsGlobal.g_objfrmPurchaseOrder == null) && (clsGlobal.g_objfrmAddPurchaseOrderItem == null))
{
    PrepareImageBar();
    return true;
}
else
{
    PrepareImageBar();
    return false;
}

}

这是我的关闭事件在每个表单上的样子。

internal static void CustomerInformationFormClosed(object sender, FormClosedEventArgs e)
    {
        clsGlobal.g_objfrmCustomerInformation = null;

        PrepareImageBar();
    }

Answer 1

我看到三种可能性：

1. 其中一个表单的 FormClosed 事件处理程序出现故障（即，可能 PurchaseOrderFormClosed 中出现故障）。
2. 您的 CloseAllForms() 方法在 catch 中执行大量工作。代码可能在那里失败。发生错误时，您是否看到 MessageBox？电子邮件发送了吗？尝试注释掉那里的所有代码，看看是否仍然出现错误。或者可能只是暂时用 MessageBox.Show(ex.ToString()) 替换 catch 中的所有代码，这样您就可以确定您所看到的异常正在发生在尝试中。
3. PrepareImageBar() 出现问题。尝试注释掉该方法，看看是否仍然出现错误。

Answer 2

我不知道异常发生在哪里，但异常可能是在修改集合的 foreach 代码块中生成的。这里，修改意味着“添加”或“删除”，类似于：

foreach(var item in collection)    { collection.Add(other);}

枚举时不能修改集合。

---

更新

要查找代码中发生的位置，在调试时，您可以检查“异常”对话框中的“用户未处理选项”(Ctrl+Alt+E)。但是，请注意，要使用此选项，VS 必须在“调试”选项中设置“仅启用我的代码”。

Answer 3

我见过这个错误：
该错误显然只出现在某些 Windows 安装上，而且我从未通过调试在开发环境中出现过该错误，只有完整的应用程序。

这是 VisualBasic.PowerPacks 中的一个错误。

请参阅此处获取解决方案< /a> （参见博客末尾）。

您基本上必须重写表单 Dispose() 方法并手动处理所有 VisualBasic Powerpack 项目。