CHANGE_OPEN_CLOSE FORM WITH BUTTONS Thiết kế Form1,2,3,4 sau: Ta mở rộng nhiều Form theo ý thích cách từ hình giao diện chọn sau: Project  Add Windows Form…  Window Form Click button1-Form1 Code: Public Class Form1 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Form2.Show() End Sub End Class Click button1 2-Form2 Code: Public Class Form2 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Form1.Show() Me.Close() End Sub Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click Form3.Show() End Sub End Class Click button1 2-Form3 Code: Public Class Form3 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Form2.Show() Me.Close() End Sub Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click Form4.Show() End Sub End Class Click button1-Form4 Code: Public Class Form4 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Form3.Show() Me.Close() End Sub End Class