对于每个<项目>在CheckedListBox中。 <项目>返回对象而不是控制 [英] For each <item> in CheckedListBox. <item> returns as Object and not as Control

问题描述

我有一个CheckedListBox以前填充。我想通过CheckedListBox中的所有项目循环使用for each / next，并对checkedlistbox的每个迭代元素执行大量填充操作。

示例代码：

 对于CheckedListBox1.Items中的每个项目
 
如果item.Checked = True然后
 
'做类似
的东西item.BackColor = Color.Blue 
 
 else 
 
'做其他的东西
 item.BackColor = Color.Brown 
 
 End If 
 
 Next 
  

问题在于对象类型，而不是控制类型。如果我强制迭代变量为复选框，它会抛出一个InvalidCastException，说该类型System.String不能与类型System.Windows.Forms.CheckBox关联

<我知道我可以很容易地解决这个问题，但是我想为每个/下一个循环使用一个循环，因为我在这个循环中有很多代码（并且不能使用），并且总是直接对象希望避免，我真的需要代码尽可能简单。

我实际上花了一个下午寻找这个，但无法找到任何答案。 >

解决方案 CheckedListBox 不是 CheckBox 控件。

它没有包装对象的集合。

CheckedListBox控件是一个简单的控件，只能显示一个简单的项目清单;这听起来像你正在寻找更强大的东西。 （例如，如果没有所有者绘图，就不可能改变单个项目的背景颜色）

您应该使用 ListView （将code> CheckBoxes 属性设置为true）。
然后你可以遍历 ListViewItem code> Items 集合中的code>实例。


I have a CheckedListBox previously populated. I want to loop with a "for each / next" through all items in the CheckedListBox and do a lot of "stuff" with each iteration element of the checkedlistbox.

example code:

    For Each item In CheckedListBox1.Items

        If item.Checked = True Then

            'do stuff like
            item.BackColor = Color.Blue

        Else

            'do other stuff
            item.BackColor = Color.Brown

        End If

    Next

the problem is that is an 'Object' type and not a 'Control' type. If I force the iteration var As CheckBox, it throws an InvalidCastException saying that type 'System.String' can't be associated with type 'System.Windows.Forms.CheckBox'

I know I can easily work around this but I want to use a for each /next loop since I have a lot of code in that loop (and With can't be used) and always poiting directly to the object is something I wish to avoid and I really need the code to be as simple as possible.

I actually spent one afternoon looking for this but couldn't find any answer.

解决方案

A CheckedListBox is not a collection of CheckBox controls.
It does not have a collection of wrapper objects.

The CheckedListBox control is a simple control that can only display a plain list of items; it sounds like you're looking for something more powerful. (For example, it is impossible to change the background color of an individual item without owner-drawing)

You should use a ListView (with the CheckBoxes property set to true) instead.
You can then loop through the ListViewItem instances in its Items collection.

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