'自定义控件代码
Public Class TestControl

    Dim MouseDownPt As Point

    Public Sub New()

        ' 此调用是 Windows 窗体设计器所必需的。
        InitializeComponent()

        ' 在 InitializeComponent() 调用之后添加任何初始化。
        Me.SetStyle(ControlStyles.ContainerControl, True)
    End Sub

    Private Sub TestControl_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseDown
        MouseDownPt = e.Location
    End Sub

    Private Sub TestControl_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseMove
        If e.Button = Windows.Forms.MouseButtons.Left Then
            Dim dx As Integer = e.X - MouseDownPt.X
            Dim dy As Integer = e.Y - MouseDownPt.Y
            Me.Location = New Point(Me.Location.X + dx, Me.Location.Y + dy)
        End If
    End Sub

End Class

'测试窗体代码（窗体添加一个TestControl1控件）
Public Class Form1

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim NewBtn As New Button
        Dim NewCheckBox As New CheckBox
        Me.TestControl1.Controls.Add(NewBtn)
        Me.TestControl1.Controls.Add(NewCheckBox)
        NewBtn.Text = "Button1"
        NewBtn.Location = New Point(10, 10)
        NewCheckBox.Text = "CheckBox1"
        NewCheckBox.Location = New Point(10, 50)
    End Sub

    
End Class