甜老师，在麻烦你一下。单击“是”或“否”都退出系统了，

Public Dim nfi As new System.Windows.Forms.NotifyIcon \'定义通知区域小图标
Public Dim cms As new System.Windows.Forms.ContextMenuStrip \'定义右键菜单
\'菜单按钮点击事件
Public Sub Menu1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)
Dim btn As WinForm.Button
MessageBox.Show("你是否退出管理系统?","提示", MessageBoxButtons.YesNo, MessageBoxIcon.Question)
BaseMainForm.Visible = True
BaseMainForm.Close
End Sub
\'图标双击事件
Public Sub ICON_DoubleClick(ByVal sender As System.Object, ByVal e As System.EventArgs)
baseMainform.visible=True \'设置主窗体显示
End Sub

 叫你看帮助文档你有看过么？

 If MessageBox.Show("你是否退出管理系统?","提示", MessageBoxButtons.YesNo, MessageBoxIcon.Question) = DialogResult.Yes Then
    BaseMainForm.Visible = True
    BaseMainForm.Close
End If