Private Sub MenuItem2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuItem2.Click
If frm_backdata Is Nothing OrElse frm_backdata.IsDisposed Then
frm_backdata = New FrmBackData
frm_backdata.Show()
Else
frm_backdata.Activate()
frm_backdata.WindowState = FormWindowState.Normal
End If
End Sub
主要是在form2中要设置form3的父窗体是form1的实例:
Public Sub New(ByVal a As Object) ‘a是form1中创建form2的实例时传递过来的参数me
MyBase.New()
'该调用是 Windows 窗体设计器所必需的。
InitializeComponent()
'在 InitializeComponent() 调用之后添加任何初始化
m = CType(a, Form1)
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim newform As New Form3()
newform.MdiParent = m
newform.Show()
End Sub