https://github.com/oscarsun72/how_to_close_specific_form_ithelp_WindowsApp

臉書直播

C++自修入門實境秀、C++ Primer Fifth Edition研讀秀

第74集：

感恩感恩 南無阿彌陀佛

Public Class Form2
    Private Sub Form2_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Dim frm1 = Application.OpenForms("Form1")
        'frm1.Close() '不能關掉，因為是整個應用程式main()的入口，關掉Form1就等於結束應用程式了
        '除非在應用程式屬性中另外指派一個main()入口的物件（即在應用程式屬性中「啟動表單」的選項，不能設為Form1）
        '或在程式關閉模式，不要選擇「啟動表單關閉時」這個選項
        frm1.Visible = False
    End Sub

    Private Sub Form2_FormClosing(sender As Object, e As FormClosingEventArgs) Handles MyBase.FormClosing
        Dim frm1 = Application.OpenForms("Form1")
        frm1.Visible = True
    End Sub
End Class

Public Class Form1
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim frm2 As New Form2
        frm2.Show()
    End Sub
End Class

如果是「整個程式都結束」的話
可以參考這篇