C# MenuStrip Visible=false bug的解决方案

 自从VS2005以后，MS推荐用MenuStrip来代替原来的MainMenu，但是MenuStrip在设置菜单项Visible=false后，表面上看是好用的，实际上键盘上下移动菜单却会出现空白的现象。。。。。。

/// <summary> /// MenuStrip当设置Visible的时候，键盘上下移动菜单会出现空白的bug /// MS说： Please also note that this issue is purely visual, there's no functionality loss. /// 观众说：Fix these problems instead of offering lame excuses /// </summary> public class ExMenuStrip : ContextMenuStrip { private IList<ToolStripItem> itemCollecton = new List<ToolStripItem>(); public ExMenuStrip() { itemCollecton.Clear(); this.ItemAdded += new ToolStripItemEventHandler(ExMenuStrip_ItemAdded); this.ItemRemoved += new ToolStripItemEventHandler(ExMenuStrip_ItemRemoved); } #region MenuStrip的Bug void ExMenuStrip_ItemRemoved(object sender, ToolStripItemEventArgs e) { if (itemCollecton.Contains(e.Item)) { itemCollecton.Remove(e.Item); } } //每次添加的时候保存起来，设visible的时候自动重排一下菜单 void ExMenuStrip_ItemAdded(object sender, ToolStripItemEventArgs e) { e.Item.AvailableChanged -= new EventHandler(Item_AvailableChanged); e.Item.AvailableChanged += new EventHandler(Item_AvailableChanged); if (!itemCollecton.Contains(e.Item)) { if (this.Items.IndexOf(e.Item) == this.Items.Count - 1) { itemCollecton.Add(e.Item); } else { //处理以Items.Insert()方式Add的情况 itemCollecton.Insert(this.Items.IndexOf(e.Item), e.Item); } } } void Item_AvailableChanged(object sender, EventArgs e) { ReArrangeItems(); } void ReArrangeItems() { this.ItemAdded -= new ToolStripItemEventHandler(ExMenuStrip_ItemAdded); this.ItemRemoved -= new ToolStripItemEventHandler(ExMenuStrip_ItemRemoved); this.Items.Clear(); for (int i = 0; i < itemCollecton.Count; i++) { if (itemCollecton[i] != null && itemCollecton[i].Available) { this.Items.Add(itemCollecton[i]); } } this.ItemAdded += new ToolStripItemEventHandler(ExMenuStrip_ItemAdded); this.ItemRemoved += new ToolStripItemEventHandler(ExMenuStrip_ItemRemoved); } #endregion }