如何检测MenuStrip何时将其中一个项目扩展到其子项目？

Question

我有这个MenuStrip左停靠在一个形式，LayoutStyle = VerticalStackWithOverflow，我写了这两个事件处理程序，以使其项目显示，只有当用户在MenuStrip中移动鼠标的文本：

Private Sub MenuStripMainMenu_MouseEnter(sender As Object, e As EventArgs) Handles MenuStripMainMenu.MouseEnter 
    For Each c In MenuStripMainMenu.Items.OfType(Of ToolStripItem) 
     c.DisplayStyle = ToolStripItemDisplayStyle.ImageAndText 
    Next 
End Sub 

Private Sub MenuStripMainMenu_MouseLeave(sender As Object, e As EventArgs) Handles MenuStripMainMenu.MouseLeave, MenuStripMainMenu.LostFocus 
    For Each c In MenuStripMainMenu.Items.OfType(Of ToolStripItem) 
     c.DisplayStyle = ToolStripItemDisplayStyle.Image 
    Next 
End Sub 

虽然这是工作好的，一些MenuItems有自己的MenuItems（作为选择树），当用户从根菜单中移动鼠标到选项时，MenuStrip缩回到它的“仅图标”模式，所以展开的菜单看起来很笨拙。

有没有什么办法可以检测到MenuStrip的某个项目扩展到它的子项目，所以我可以挂上适当的调整例程？

非常感谢！

编辑

这DonBoitnott's answer移植到VB.NET，我只在MenuDeactivate处理增加了随访，以带退缩到菜单被停用之后仅适用于图像：

Private MenuStripMainMenu_activated As Boolean = False 

Private Sub MenuStripMainMenu_MenuActivate(sender As Object, e As EventArgs) Handles MenuStripMainMenu.MenuActivate 
    MenuStripMainMenu_activated = True 
End Sub 

Private Sub MenuStripMainMenu_MenuDeactivate(sender As Object, e As EventArgs) Handles MenuStripMainMenu.MenuDeactivate 
    MenuStripMainMenu_activated = False 
    MenuStripMainMenu_MouseLeave(sender, e) 
End Sub 

Private Sub MenuStripMainMenu_MouseEnter(sender As Object, e As EventArgs) Handles MenuStripMainMenu.MouseEnter 
    For Each c In MenuStripMainMenu.Items.OfType(Of ToolStripItem) 
     c.DisplayStyle = ToolStripItemDisplayStyle.ImageAndText 
    Next 
End Sub 

Private Sub MenuStripMainMenu_MouseLeave(sender As Object, e As EventArgs) Handles MenuStripMainMenu.MouseLeave 
    If Not MenuStripMainMenu_activated Then 
     For Each c In MenuStripMainMenu.Items.OfType(Of ToolStripItem) 
      c.DisplayStyle = ToolStripItemDisplayStyle.Image 
     Next 
    End If 
End Sub 

Answer 1

您目前拥有的事件的组合，并加入MenuActivate和MenuDeactivate可制成表现：

public partial class Form1 : Form 
    { 
     private Boolean _activated = false; 

     public Form1() 
     { 
      InitializeComponent(); 
     } 

     private void menuStrip1_MouseEnter(Object sender, EventArgs e) 
     { 
      foreach (var c in menuStrip1.Items.OfType<ToolStripItem>()) 
       c.DisplayStyle = ToolStripItemDisplayStyle.ImageAndText; 
     } 

     private void menuStrip1_MouseLeave(Object sender, EventArgs e) 
     { 
      if (!_activated) 
      { 
       foreach (var c in menuStrip1.Items.OfType<ToolStripItem>()) 
        c.DisplayStyle = ToolStripItemDisplayStyle.Image; 
      } 
     } 

     private void menuStrip1_MenuActivate(Object sender, EventArgs e) 
     { 
      _activated = true; 
     } 

     private void menuStrip1_MenuDeactivate(Object sender, EventArgs e) 
     { 
      _activated = false; 
      foreach (var c in menuStrip1.Items.OfType<ToolStripItem>()) 
       c.DisplayStyle = ToolStripItemDisplayStyle.Image; 
     } 
    }