VB.NET自定义控件（自​​定义图形）刷新问题 [英] VB.NET Custom Control (custom drawing) Refresh issue

问题描述

我创建了一个包含2个项目的简单解决方案。第一个项目（类库）包含一个名为Container的自定义控件，该控件将自己绘制为圆角。第二个项目（Windows窗体）是一个测试应用程序。

I've created a simple solution with 2 projects. The 1st project (class library) contains a custom control called Container which draws itself with rounded corners. The 2nd project (windows forms) is a test application.

如果我在第二个项目的主Form中添加一个Container实例，则会很好地显示圆角。同样，当我运行第二个项目时，我可以看到容器。

If I add a Container instance to main Form in the 2nd project it shows the rounded corners nicely. Also when I run the 2nd project I can see the Container.

但是，当我开始移动表单时（单击并按住标题栏），尤其是当我非常移动它时很快，所有图形都被弄乱了，一遍又一遍地绘制，但没有先清除它的表面...

However when I start moving the form (click and hold the title bar), especially when I move it very fast, all the drawing is messed up, drawn over and over again but not clearing it's surface first...

我可以在Form1中调用Container1.Refresh（）。 Move事件，但是我不想每次都设置此事件，因为这也意味着我必须在 Form1.Resize 事件中调用Container1.Refresh（），谁知道这其他事件...

I can call Container1.Refresh() in the Form1.Move event, but I don't want to set this every time because this also means I have to call Container1.Refresh() in the Form1.Resize event and who knows which other event...

在Container（控件）类本身中是否有一个事件，我应该调用Me.Refresh（）或Me.Update（）或Me。 Invalidate（）？

Is there an event in the Container (control) class itself where I should call Me.Refresh() or Me.Update() or Me.Invalidate() ?

供参考（Form1.vb）

For reference (Form1.vb)

Public Class Form1

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

End Sub

Private Sub Form1_Move(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Move
    Me.Container1.Refresh()
End Sub
End Class

（Container.vb）：

for reference (Container.vb):

Imports System.Windows.Forms
Imports System.Drawing
Imports System.Drawing.Drawing2D

Public Class Container : Inherits Control
    Private _Gp As GraphicsPath

    Private Sub Container_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles Me.Paint

        Dim r As Rectangle = e.ClipRectangle
        Dim gp As New GraphicsPath
        Dim cs As Integer = 25 'CornerSize'

        r.Inflate(-5, -5)

        gp.AddArc(r.X, r.Y, cs, cs, 180, 90)
        gp.AddArc(r.X + r.Width - cs, r.Y, cs, cs, 270, 90)
        gp.AddArc(r.X + r.Width - cs, r.Y + r.Height - cs, cs, cs, 0, 90)
        gp.AddArc(r.X, r.Y + r.Height - cs, cs, cs, 90, 90)

        Dim t As Single = cs / 2 + r.Y
        gp.AddLine(r.X, r.Y + r.Height - cs, r.X, t)

        e.Graphics.SmoothingMode = Drawing.Drawing2D.SmoothingMode.AntiAlias
        e.Graphics.DrawPath(Pens.Black, gp)
    End Sub

End Class

推荐答案

这是您的问题：

Dim r As Rectangle = e.ClipRectangle

将其更改为：

Dim r As Rectangle = Me.ClientRectangle

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