I want to open form2 from a button on form1. Both of these forms are mdiChildren. The parent is formParent.
If form2 is not modal then it could disappear behind form1 after it has been opened and then if the user clicks the button on form1 again, a new instance of form2 would be created and any data that could have been entered is lost.
Firstly how would you open the same running instance of form2 in case the user clicks the button on form1 twice. Or perhaps a better question is how do you tell if there is a running instance of a form so you can choose to create a new instance or to open the running instance?
I am using VB.Net by the way.
Wing
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Okay what if the user clicks the button in form1 and creates an instance of form2.
Now frm2 is not equal to nothing.
He changes his mind and cancels form2.
frm2 is not nothing anymore. so the code above will no longer open form2.
How do you make frm2 equal nothing again. Where would you set it equal to nothing so that the button on form1 can open it again?
Wing
YES user is the king of application... he/she can do any thing... but its too simple to play with that user... you just have to add another check
Dim frm2 As Form2 = Nothing ' Declare that in form1 global variable
'button1 on form1 clicks
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
If frm2 Is Nothing Then
frm2 = New Form2()
frm2.MdiParent = Me.MdiParent
frm2.Show()
ElseIf frm2.IsDisposed Then ' add this check.... dont OR this with the above check
frm2 = New Form2()
frm2.MdiParent = Me.MdiParent
frm2.Show()
Else
frm2.Focus()
End If
End Sub
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by: DespPosted on 2003-07-04 at 05:24:16ID: 8856065
you need to create a Form2 instance in Form1 and access that ,,, if that doestn exist create that ... if that exist set focus to that instance
Dim frm2 As Form2 = Nothing ' Declare that in form1 global variable
'button1 on form1 clicks
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
If frm2 Is Nothing Then
frm2 = New Form2()
frm2.MdiParent = Me.MdiParent
frm2.Show()
Else
frm2.Focus()
End If
End Sub