我有一个自定义UserControl,它有一个StatusStrip。所以,当用户拖动这个状态条的角落时,我调整了这个控件的大小。但是,调整大小不是很好:在调整大小期间可以在父控件上观察到临时白色区域,有时如果调整大小太快,则用户“失去”控件(停止调整大小)。优化控件大小调整
Option Infer On
Public Class FloattingGrid
Inherits System.Windows.Forms.UserControl
Dim mouseDownLocation As Nullable(Of Point)
Private Sub StatusStrip1_MouseMove(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles StatusStrip1.MouseMove
If mouseDownLocation.HasValue Then
Dim newPosition = Cursor.Position
Dim dx = newPosition.X - mouseDownLocation.Value.X
Dim dy = newPosition.Y - mouseDownLocation.Value.Y
'Dim oldRect = New Rectangle(Me.Location, Me.Size)'
Me.Size = New Size(Me.Width + dx, Me.Height + dy)
mouseDownLocation = newPosition
If Me.Parent IsNot Nothing Then
'Me.Parent.Invalidate(oldRect) '
Me.Parent.Refresh()
End If
Else
If e.X > Me.Width - 20 Then
If Cursor <> Cursors.SizeNWSE Then Cursor = Cursors.SizeNWSE
Else
If Cursor = Cursors.SizeNWSE Then Cursor = Cursors.Default
End If
End If
End Sub
Private Sub StatusStrip1_MouseLeave(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles StatusStrip1.MouseLeave
Cursor = Cursors.Default
mouseDownLocation = Nothing
'Me.ResumeLayout() '
End Sub
Private Sub StatusStrip1_MouseDown(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles StatusStrip1.MouseDown
If Cursor = Cursors.SizeNWSE Then
'Me.SuspendLayout() '
mouseDownLocation = Cursor.Position
End If
End Sub
Private Sub StatusStrip1_MouseUp(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles StatusStrip1.MouseUp
mouseDownLocation = Nothing
'Me.ResumeLayout()'
End Sub
' Private Sub FloattingGrid_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseMove '
' End Sub '
Private Sub FloattingGrid_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Me.ResizeRedraw = True
End Sub
End Class
我认为这种行为可以通过父母的的Invalidate引起的。有没有办法只是BeginInvalidate,而不是等到父节点全部失效?
有效地,在调用parent.Refresh()而不是parent.Invalidate(oldRect)之后,白色区域消失。但是,当移动速度更快时,我总是失去控制。我不调整StatusStrip的大小,我直接调整UserControl的大小(statusStrip停靠在底部) – serhio 2011-05-17 10:24:04
@serhio:是的,调用'Refresh'会立即*重绘*。这就是白色区域消失的原因。它们只是白色的,因为Windows还没有绘制任何东西。这样做的副作用是计算机开始滞后,因为它无法一下子跟上所有这一切。这就是为什么它通常不会画这些区域,为什么当你强迫它,当你开始快速移动时,它似乎失去了控制。这是一个折中,你必须选择哪一个更容易被你接受,或者使用双缓冲等替代策略(这只是一个窍门,而不是真正的修复)。 – 2011-05-17 10:26:20
一个原因可能是我仅在StatusStrip_MouseMove上跟随移动,并且如果调整大小比鼠标移动慢,那么鼠标离开StatusStip区域并且不再调用任何移动......另一件事是Refresh()似乎重画所有的父母,而不仅仅是控制古代地区 - 它也需要时间... – serhio 2011-05-17 10:31:52