实际上你需要遍历当前显示的ListViewItem
物体和toggle the Selected
与鼠标移动相交的项目的属性。这是实现这一目标的方法:
声明一个名为的类成员startPoint
:
Private startPoint As Point
处理MouseDown
设置起始位置的事件:
Private Sub ListView1_MouseDown(sender As Object, e As MouseEventArgs) Handles ListView1.MouseDown
Dim s = DirectCast(sender, ListView)
If e.Button = MouseButtons.Left AndAlso
s.Items.Count > 1 Then
startPoint = e.Location
End If
End Sub
处理MouseMove
事件至toggle the Selected
财产:
Private Sub ListView1_MouseMove(sender As Object, e As MouseEventArgs) Handles ListView1.MouseMove
Dim s = DirectCast(sender, ListView)
If e.Button = MouseButtons.Left AndAlso s.Items.Count > 1 Then
Dim selRect As New Rectangle(Math.Min(startPoint.X, e.Location.X),
Math.Min(startPoint.Y, e.Location.Y),
Math.Abs(e.Location.X - startPoint.X),
Math.Abs(e.Location.Y - startPoint.Y))
Dim cr = s.ClientRectangle
'Toggle selection...
For Each item In s.Items.Cast(Of ListViewItem).
Where(Function(x) x.Bounds.IntersectsWith(cr))
item.Selected = selRect.IntersectsWith(item.Bounds)
Next
End If
End Sub
一个快速演示来检查:
但是,如果您有许多项目,而客户区域的大小不足以显示所有项目,因此垂直滚动条可见,该怎么办?你会得到这样的东西:
正如您所看到的,垂直滚动条不会移动,您将无法继续选择/取消选择隐藏的项目。为了解决这个问题,我们需要更多代码:
导入签名获取滚动位置 https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-getscrollpos在你的班级中的某个地方运行:
Imports System.Runtime.InteropServices
'...
<DllImport("user32.dll", CharSet:=CharSet.Auto)>
Private Shared Function GetScrollPos(hWnd As IntPtr,
nBar As Orientation) As Integer
End Function
Note: Passing a System.Windows.Forms.Orientation
value instead of an Interger
.
改变MouseDown
活动至:
Private Sub ListView1_MouseDown(sender As Object, e As MouseEventArgs) Handles ListView1.MouseDown
Dim s = DirectCast(sender, ListView)
If e.Button = MouseButtons.Left AndAlso
s.Items.Count > 1 Then
Dim vsp = GetScrollPos(s.Handle, Orientation.Vertical)
Dim yOffset = s.Font.Height * vsp
startPoint = New Point(e.X, e.Y + yOffset)
End If
End Sub
And the MouseMove
活动至:
Private Sub ListView1_MouseMove(sender As Object, e As MouseEventArgs) Handles ListView1.MouseMove
Dim s = DirectCast(sender, ListView)
If e.Button = MouseButtons.Left AndAlso s.Items.Count > 1 Then
Dim vsp = GetScrollPos(s.Handle, Orientation.Vertical)
Dim yOffset = s.Font.Height * vsp
Dim selRect As New Rectangle(Math.Min(startPoint.X, e.Location.X),
Math.Min(startPoint.Y - yOffset, e.Location.Y),
Math.Abs(e.Location.X - startPoint.X),
Math.Abs(e.Location.Y - startPoint.Y + yOffset))
Dim cr = s.ClientRectangle
'Toggle selection...
For Each item In s.Items.Cast(Of ListViewItem).
Where(Function(x) x.Bounds.IntersectsWith(cr))
item.Selected = selRect.IntersectsWith(item.Bounds)
Next
'Scroll if needed...
Dim p = s.PointToClient(Cursor.Position)
Dim lvi = s.GetItemAt(p.X, p.Y)
If lvi Is Nothing Then Return
Dim fh = s.Font.Height
If lvi.Index > 0 AndAlso (p.Y - lvi.Bounds.Height * 1.5) <= fh Then
s.Items(lvi.Index - 1).EnsureVisible()
ElseIf lvi.Index < s.Items.Count - 1 AndAlso
(p.Y + lvi.Bounds.Height * 1.5) > (s.Height - fh) Then
s.Items(lvi.Index + 1).EnsureVisible()
End If
End If
End Sub
结果是:
Here https://pastebin.com/vwnTUwByVB.NET 自定义 ListView 控件解决了这个问题,并且another https://pastebin.com/9TzmmfEJ in C#.