.net - 如何从ListView控件的单个项目中删除复选框？

Question

我有一个带有“名称”，“期望”，“总计”列的ListView，我想在末尾添加另一列“重新计数”。理想情况下，仅当“期望”值大于“总计”值时，“重新计数”列才会有一个复选框。

到目前为止，我已经有了带有列的ListView并可以在左侧添加一个复选框，但是该复选框不在列标题下(尽管我可能可以在其中放置没有值的另一列来解决该问题)，它在所有记录上。

有人有什么想法我还能做什么？

Answer 1

如果您愿意忍受P/Invoke的苦恼以访问内置于 native Windows控件中的功能，但.NET FW不公开此功能，则这实际上相对容易实现。

我向in my answer here演示了如何使用TreeView控件完成此完全相同的操作，并考虑到ListView与TreeView有多么相似，因此可以非常相似地使用ListView来完成此操作也就不足为奇了。

这是所需的所有代码(确保已为Imports命名空间添加了System.Runtime.InteropServices声明):

' 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

然后，您可以像这样简单地调用上述方法:

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

制作看起来像这样的东西(单击番茄和 cucumber 项目的“隐藏检查”按钮之后):