Question

我有以下代码，它是表单中的私有方法，并从表单中检索所有上下文菜单。我觉得，它应该是那么简洁。将不胜感激任何建议。

  private IEnumerable<ContextMenuStrip> GetContextMenus()
    {
        var type = this.GetType();
        var fields = type.GetFields(BindingFlags.NonPublic | BindingFlags.Instance);
        var contextMenus = fields.Where(f => f.GetValue(this).GetType() == typeof(ContextMenuStrip));
        var menus = contextMenus.Select(f=> f.GetValue(this));
        return menus.Cast<ContextMenuStrip>();        
    }

Answer 1

您是否乐意加入ContextMenuStrip的子类？如果是这样，我会使用：

return GetType().GetFields(BindingFlags.NonPublic | BindingFlags.Instance)
                .Select(field => field.GetValue(this))
                .OfType<ContextMenuStrip>();

Answer 2

var query = (from f in GetType().GetFields(
                 BindingFlags.NonPublic | BindingFlags.Instance)
            select f.GetValue(this)).OfType<ContextMenuStrip>();

Answer 3

如果代码在表单中，您可能希望完全避免反射，只需遍历Controls集合，如：

var controls = from Control c in Controls.AsQueryable()
               where c is ContextMenuStrip
               select c;

或un-LINQed变体

IEnumerable<ContextMenuStrip> result = new List<ContextMenuStrip>();
foreach (var control in Controls)
{
   ContextMenuStrip menuStrip = (control as ContextMenuStrip)
   if (menuStrip != null )
   {
     result.Add(menuStrip);
   }
}
return result;

检索具有指定类型的字段的值

3 个答案: