[vb.net] 열려있는 폼을 확인하여 없으면 폼실행(OpenForms Check) > vb.net

폼이 열려 있는지 확인(Check if form is Opened)

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

If myForm.IsHandleCreated then

   myForm is open

End If

우수답변 : 

Private Sub OpenWindowsForm(ByVal FormName As String)

    Dim instForm As Form = Application.OpenForms.OfType(Of Form)().Where(Function(frm) frm.Name = FormName).SingleOrDefault()

    If instForm Is Nothing Then

        Dim frm As New Form

        frm = DirectCast(CreateObjectInstance(FormName), Form)

        frm.MdiParent = Me

        Me.Panel1.Controls.Add(frm)

        Me.Panel1.Tag = frm

        frm.Show()

    Else

        instForm.Select()

        instForm.WindowState = FormWindowState.Maximized

        instForm.BringToFront()

    End If

End Sub



Public Function CreateObjectInstance(ByVal objectName As String) As Object

    Dim obj As Object

    Try

        If objectName.LastIndexOf(".") = -1 Then

            objectName = [Assembly].GetEntryAssembly.GetName.Name & "." & objectName

        End If



        obj = [Assembly].GetEntryAssembly.CreateInstance(objectName)



    Catch ex As Exception

        obj = Nothing

    End Try

    Return obj

End Function

Private Sub btnBusqueda_Click(sender As Object, e As EventArgs) Handles btnBusqueda.Click

    OpenWindowsForm("Busqueda")

End Sub



Private Sub btnCalendario_Click_1(sender As Object, e As EventArgs) Handles btnCalendario.Click

    OpenWindowsForm("Calendario")

End Sub

Dim frmCollection = System.Windows.Forms.Application.OpenForms

If frmCollection.OfType(Of Form2).Any Then

    frmCollection.Item("Form2").Activate()

Else

    Dim newForm2 = New Form2

    newForm2.Show()

End If

    Dim xChildWindows = Application.OpenForms.OfType(Of frmForm2)

    If xChildWindows.Any Then

        xChildWindows.First().Focus() 'Focus if exists

    Else

        Dim xfrmNew As New frmForm2() 'Open window if doeasn't exists

        xfrmNew.MdiParent = Me

        xfrmNew.Show()

    End If

Dim formText As String

Dim prevText As String



 Private Sub OpenForm(ByVal frm As Windows.Forms.Form)

        formText = frm.Text

        If formText = prevText Then Exit Sub

        CloseForms()

        ' Make it a child of this MDI form before showing it.

        frm.MdiParent = Me

        frm.Show()

        frm.Location = New Point(0, 0)

        prevText = formText

    End Sub



    Private Sub CloseForms()

        For Each ChildForm As Form In Me.MdiChildren

            ChildForm.Close()

        Next

    End Sub



    Private Sub NewToolStripButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles PayablesToolStripMenuItem.Click

            OpenForm(frmPayables)

    End Sub