Dim canvas As New ShapeContainer
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' To draw anoval, substitute
' OvalShapefor RectangleShape.
DimtheShape As NewRectangleShape
' Set theform as the parent of the ShapeContainer.
canvas.Parent = Me
' Set theShapeContainer as the parent of the Shape.
theShape.Parent = canvas
' Set thesize of the shape.
theShape.Size = New System.Drawing.Size(200,300)
' Set thelocation of the shape.
theShape.Location = New System.Drawing.Point(100,100)
' To draw arounded rectangle, add the following code:
theShape.CornerRadius = 12
theShape.FillStyle = FillStyle.Solid
theShape.FillColor = Color.Red
绘制线条采用Draw开头的方法，颜色参数用Pen类；
绘制有填充色的封闭图形采用Fill开头的方法，颜色参数用Brush类；
例如：
'绘制一个实心圆，该圆在：直线x=200，y=200，x=200+100，y=200+100所划矩形区域内
Me.CreateGraphics.FillEllipse(New SolidBrush(Color.Orange), 200, 200, 100, 100)
'绘制一个空心圆，该圆在：直线x=200，y=200，x=200+100，y=200+100所划矩形区域内
Me.CreateGraphics.DrawEllipse(New Pen(Color.Black), 200, 200, 100, 100)
你应该填充这个矩形，比如说在你画的矩形上填充蓝色，要加上下面的语句
Dim myBrush As New SolidBrush(Color.Blue)
e.Graphics.FillRectangle(myBrush, 10,10, 100,100)
这个类继承自Panel，把它加到你的项目里面，先运行一下，然后从工具箱里把它拖到窗体上，然后再向里面添加其它控件就可以了，支持Shift加选，Alt减选
Imports System.Linq
Imports System.Collections
Public Class MyPanel
Inherits Panel
' 选择模式，相交还是包含
Enum SelectMode
Intersects
Contains
End Enum
Dim down As New Point(-1, -1)
Dim rect As Rectangle
Dim selected As New List(Of Control)
Dim editting As IEnumerable(Of Control)
Dim mode As SelectMode = SelectMode.Contains
Dim shift, alt As Boolean
Public Sub New()
Me.DoubleBuffered = True
End Sub
Protected Overrides Sub OnMouseDown(e As MouseEventArgs)
MyBase.OnMouseDown(e)
down = e.Location
editting = selected.ToArray().ToList()
OnMouseMove(e)
End Sub
Protected Overrides Sub OnMouseMove(e As MouseEventArgs)
MyBase.OnMouseMove(e)
If e.Button = Windows.Forms.MouseButtons.Left Then
Dim loc As New Point(Math.Min(down.X, e.X), Math.Min(down.Y, e.Y))
Dim size As New Size(Math.Abs(down.X - e.X), Math.Abs(down.Y - e.Y))
rect = New Rectangle(loc, size)
Dim cs As New List(Of Control)
For Each c In Controls
cs.Add(c)
Next
Dim a = cs.Where(Function(n As Control) (mode = SelectMode.Contains And rect.Contains(n.Bounds)) Or (mode = SelectMode.Intersects And rect.IntersectsWith(n.Bounds)))
If shift Then editting = a.Union(selected) Else If alt Then editting = selected.Except(a) Else editting = a
Invalidate()
End If
End Sub
Protected Overrides Sub OnMouseUp(e As MouseEventArgs)
MyBase.OnMouseUp(e)
down = New Point(-1, -1)
selected = editting.ToList()
editting = Nothing
Invalidate()
End Sub
Protected Overrides Function ProcessKeyPreview(ByRef m As Message) As Boolean
Dim KeyCode As Keys = CInt(m.WParam) And CInt(Keys.KeyCode)
Dim d As Boolean
If m.Msg = H100 Or m.Msg = H104 Then d = True Else If m.Msg = H101 Or m.Msg = H105 Then d = False Else Return MyBase.ProcessKeyPreview(m)
If KeyCode = Keys.ShiftKey Then
shift = d
ElseIf KeyCode = Keys.Menu Then
alt = d
End If
Return MyBase.ProcessKeyPreview(m)
End Function
Protected Overrides Sub OnPaint(e As PaintEventArgs)
MyBase.OnPaint(e)
For Each c As Control In IIf(editting Is Nothing, selected, editting)
e.Graphics.DrawRectangle(New Pen(Color.Gray) With {.DashStyle = Drawing2D.DashStyle.DashDot}, c.Left - 1, c.Top - 1, c.Width + 1, c.Height + 1)
Next
If (down.X 0) Then e.Graphics.DrawRectangle(New Pen(Color.Gray) With {.DashStyle = Drawing2D.DashStyle.DashDot}, rect)
End Sub
End Class
