单击 TreeView 上的 ListView（在 TForm 上）会触发 TreeView OnChange 事件

Question

使用 Borland C++ Builder

我有一个应用程序，它带有一个自行创建的面包屑控件，位于TTreeView 控件的正上方，TListView 控件（alClient 在TForms 内）作为下拉菜单。

控件的位置是新的。意思是，实现较旧，并且以前运行良好，但我只是将面包屑控件移到 TTreeView 控件上方。

我现在注意到，从面包屑控件中单击 TListView 项目，也会触发 TTreeView OnChange 事件！ 并且选中的节点是最上面的节点。

这会导致我的设计发生冲突，因为TListView 项目单击和TTreeView Onchange 会导致显示/完成不同的事情。 哪个事件最终“获胜”也不是 100%，因此结果也是可变的。

我可以考虑在面包屑代码执行时尝试禁用TTreeView，以便忽略点击，但我想知道这是正常现象还是我遗漏了什么？

两个控件在相互显示时触发是否正常？

ListView 项目点击是通过分配以下函数的 OnClick 事件处理的：

void __fastcall TBreadcrumbListViewEx::InternalListViewClick(TObject *Sender)
{

if (FListView->Selected && FOnBreadcrumbListItemClick)
    {
    TPoint pt;
    pt = FListView->ScreenToClient(Mouse->CursorPos);

    THitTests HitTests = FListView->GetHitTestInfoAt(pt.x, pt.y);
    if ( (HitTests.Contains(htOnIcon)) || (HitTests.Contains(htOnItem)) ||
         (HitTests.Contains(htOnLabel)) || (HitTests.Contains(htOnStateIcon)) )
        {
        // This is a very precarious situation, because the FOnBreadcrumbListItemClick callback will most likely trigger building a new Breadcrumbs layout (Different Items)
        // Which causes OnData events from this control to want to access Breadcrumbs that have been deleted already
        // Therefore, get the selected Item (which will trigger OnData) and use its Index and Data members

        TListItem *Item = FListView->Selected ;

        // Next prevent any OnData event to get through and wreak havoc
        // This needs to be done *before* Hide() is called

        _releasing = true ;

        // Hide is necesary because if the FOnBreadcrumbListItemClick event takes a long time, for instance it shows a dialog,
        // this control will still be visible, yet it cannot show proper content anymore, since the OnData event is disabled
        // Hence Hide() to no show it anymore when, for instance, a dialog is showing

        Hide() ;

        FOnBreadcrumbListItemClick(this, Item->Index, BreadcrumbItem, Item->Data);

        Release(); // Close();
        }
    }

}

我一直在运行测试。 首先，我禁用了事件/回调FOnBreadcrumbListItemClick()，但问题仍然存在，即使单击该项目时没有真正发生任何事情。 我一直在尝试禁用Hide()、Release()，将Release() 替换为Close() 等。但如果其中一个仍然存在，问题仍然存在。

只有当我同时禁用 Hide() 和 Release()/Close() 时，我似乎不会遇到麻烦。直到那时我才在我的测试中不再看到TTreeView OnChange 出现。老实说，我现在什么都不确定了。

这是你所期望的吗？或者这仅仅是一个副作用，问题仍然是别的？

另外......我将如何执行回调并从视图中隐藏/删除弹出窗口，而不会“不安”TTreeView？

暂时禁用TTreeView 仍然是一种选择，但我宁愿修复这个问题，以免下次我将控件移动到其他位置时再次遇到麻烦。

Answer 1

我最终通过将消息发布到队列末尾来“修复”它，以便 TListView OnClick 事件可以尽快完成，并且鼠标事件完全被吸收，通过避免 @ OnClick 活动期间的 987654323@ 或 Release()。

void __fastcall TBreadcrumbListViewEx::InternalListViewClick(TObject *Sender)
{

if (FListView->Selected && FOnBreadcrumbListItemClick)
    {
    TPoint pt = FListView->ScreenToClient(Mouse->CursorPos);

    THitTests HitTests = FListView->GetHitTestInfoAt(pt.x, pt.y);
    if ( (HitTests.Contains(htOnIcon)) || (HitTests.Contains(htOnItem)) ||
         (HitTests.Contains(htOnLabel)) || (HitTests.Contains(htOnStateIcon)) )
        {
        PostMessage(Handle /*Destination*/, WM_APP, 0, (LPARAM)FListView->Selected);
        }
    }

}

//------------

void __fastcall TBreadcrumbListViewEx::WmApp(TMessage &Msg)
{

TListItem *ClickedItem = (TListItem*)Msg.LParam ;

if (ClickedItem)
    {

    // Next prevent any more OnData events to get through and wreak havoc
    // This needs to be done *before* Hide() is called

    _releasing = true ;

    // Hide is necesary because if the FOnBreadcrumbListItemClick event takes a long time, for instance it shows a dialog,
    // this control will still be visible, yet it cannot show proper content anymore, since the OnData event is disabled
    // Hence Hide() to no show it anymore when, for instance, a dialog is showing

    Hide() ;

    // Disable the entire breadcrumb control to avoid clicks while a dialog is up or during a lengthy process to get the data for next
    // breadcrumb layout

    BBar->Enabled = false ;

    FOnBreadcrumbListItemClick(this, ClickedItem->Index, BreadcrumbItem, ClickedItem->Data);

    BBar->Enabled = true ;

    Release();
    }

}