如何从ListView控件中删除单个项目的复选框？ [英] How can I remove the checkboxes from individual items in a ListView control?

问题描述

我有一个ListView与列'名称'，'期望'，'总'，我想添加另一个列Recount结束。只要Expected值大于Total值，Recount列就会有一个复选框。

到目前为止，并且可以在左侧添加一个复选框，但是该复选框不在列标题下（虽然我可以放置另一个没有值的列来解决这个问题），并且它在所有记录上。 / p>

任何人都有任何想法我还能做什么？

解决方案

实际上是相对简单的实现，只要你愿意忍受P / Invoke的苦恼来访问本地Windows控件内置的功能，但不是由.NET FW暴露。

我在此演示我的回答如何这个完全相同的事情可以用一个TreeView控件，并考虑ListView是如何类似于一个TreeView，应该不是特别令人惊讶，这可以以非常相同的方式与一个ListView。

这里是所有必需的代码（确保您为系统添加了 Imports 声明。 Runtime.InteropServices 命名空间）：

 'P / Invoke声明
 Private Const LVIF_STATE As整数=& H8 
私人字段LVIS_STATEIMAGEMASK As Integer =& HF000 
私人字段LVM_FIRST As Integer =& H1000 
私人字段LVM_SETITEM As Integer = LVM_FIRST + 76 
 
< StructLayout（LayoutKind.Sequential，Pack：= 8，CharSet：= CharSet.Auto）> _ 
私有结构LVITEM 
公共掩码作为整数
公共iItem作为整数
公共iSubItem作为整数
公共状态作为整数
公共stateMask作为整数
< MarshalAs（UnmanagedType.LPTStr）> _ 
 Public lpszText As String 
 public cchTextMax As Integer 
 Public iImage As Integer 
 Public lParam As IntPtr 
结构结构
 
< DllImport （user32.dll，CharSet：= CharSet.Auto）> _ 
私有共享函数SendMessage（ByVal hWnd As IntPtr，ByVal Msg As Integer，ByVal wParam As IntPtr，ByRef lParam As LVITEM）As IntPtr 
 End Function 
 
''' ; summary> 
'''隐藏ListView控件中指定项目的复选框。 
'''< / summary> 
 Private Sub HideCheckBox（ByVal lvw As ListView，ByVal item As ListViewItem）
 Dim lvi As LVITEM = New LVITEM（）
 lvi.iItem = item.Index 
 lvi.mask = LVIF_STATE 
 lvi.stateMask = LVIS_STATEIMAGEMASK 
 lvi.state = 0 
 SendMessage（lvw.Handle，LVM_SETITEM，IntPtr.Zero，lvi）
 End Sub 
  

然后你可以像这样调用上面的方法：

  Private Sub btnHideCheckForSelected_Click（ByVal sender As Object，ByVal e As EventArgs）
'隐藏当前选中的ListViewItem旁边的复选框
 HideCheckBox（myListView，myListView.SelectedItems（0） ）
 End Sub 
  

生成看起来有点像这样的东西检查按钮）：

     

I have a ListView with the columns 'Name', 'Expected', 'Total', and I want to add another column saying 'Recount' at the end. The 'Recount' column will ideally have a checkbox only if the 'Expected' value is larger than the 'Total' value.

So far I have got the ListView with columns and can add a check box on the left hand side, but that check box is not under a column heading (though I can probably put another column with no values in there to work around that) and it is on all of the records.

Anyone have any ideas what else I can do?

解决方案

This is actually relatively simple to implement, provided that you're willing to endure the drudgery of P/Invoke to access functionality built into the native Windows control, but not exposed by the .NET FW.

I demonstrate in my answer here how this exact same thing can be done with a TreeView control, and considering how similar a ListView is to a TreeView, it should not be particularly surprising that this can be done in very much the same way with a ListView.

Here's all the code that is required (make sure that you've added an Imports declaration for the System.Runtime.InteropServices namespace):

' P/Invoke declarations
Private Const LVIF_STATE As Integer = &H8
Private Const LVIS_STATEIMAGEMASK As Integer = &HF000
Private Const LVM_FIRST As Integer = &H1000
Private Const LVM_SETITEM As Integer = LVM_FIRST + 76

<StructLayout(LayoutKind.Sequential, Pack:=8, CharSet:=CharSet.Auto)> _
Private Structure LVITEM
   Public mask As Integer
   Public iItem As Integer
   Public iSubItem As Integer
   Public state As Integer
   Public stateMask As Integer
   <MarshalAs(UnmanagedType.LPTStr)> _
   Public lpszText As String
   Public cchTextMax As Integer
   Public iImage As Integer
   Public lParam As IntPtr
End Structure

<DllImport("user32.dll", CharSet:=CharSet.Auto)> _
Private Shared Function SendMessage(ByVal hWnd As IntPtr, ByVal Msg As Integer, ByVal wParam As IntPtr, ByRef lParam As LVITEM) As IntPtr
End Function

''' <summary>
''' Hides the checkbox for the specified item in a ListView control.
''' </summary>
Private Sub HideCheckBox(ByVal lvw As ListView, ByVal item As ListViewItem)
   Dim lvi As LVITEM = New LVITEM()
   lvi.iItem = item.Index
   lvi.mask = LVIF_STATE
   lvi.stateMask = LVIS_STATEIMAGEMASK
   lvi.state = 0
   SendMessage(lvw.Handle, LVM_SETITEM, IntPtr.Zero, lvi)
End Sub

And then you can simply call the above method like this:

Private Sub btnHideCheckForSelected_Click(ByVal sender As Object, ByVal e As EventArgs)
   ' Hide the checkbox next to the currently selected ListViewItem
   HideCheckBox(myListView, myListView.SelectedItems(0))
End Sub

Producing something that looks a bit like this (after clicking the "Hide Check" button for both the tomato and the cucumber items):

     

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