📅  最后修改于: 2022-03-11 14:57:03.828000             🧑  作者: Mango
Imports System.Linq ' need to add
If Application.OpenForms().OfType(Of Form2).Any Then
MessageBox.Show("Opened")
Else
Dim f2 As New Form2
f2.Text = "form2"
f2.Show()
End If