simple question - Form progression

Guys,

I am developing an app in VB.NET, I'm pretty new to this so be gentle.

I have a "homepage" for the app, this has a series of 7 buttons on that progress to a similar screen for the section clicked. Each of the sectional forms have more buttons on, each relating to a specific task.

I am opening the new forms on button click with this code . .

Code:

---

   
    Private Sub btn_procurement_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn_procurement.Click
        Dim frm_procurement As New frm_procurement
        frm_procurement.ShowDialog()
    End Sub

---

Should I be closing frm_homepage when the users navigate to the new form ? If so, how. I notice that each open form shows as a new item on the taskbar.

Thanks
Bob

Forms have a ShowInTaskbar property which you should set to false for each of the child forms you are opening.

Thanks Squirrel :blush:

I have a back button on each form with me.close assigned on click.

I also need a "Home" button, that will close all other forms and return to the homepage ???

Thanks
Bob

Try this:

1, Create a class module called forms collection and add this code:

VB Code:

Public Class FormsCollection
    Inherits System.Collections.CollectionBase
 
    Public Sub Add(ByVal formToAdd As Form)
        MyBase.InnerList.Add(formToAdd)
    End Sub
 
    Public Sub Remove(ByVal formToRemove As Form)
        MyBase.InnerList.Remove(formToRemove)
    End Sub
End Class

2, Create a module containing the following line of code:

VB Code:

Public forms As New FormsCollection

3, In the "Create new form" button's click event handler add something like this:

VB Code:

Dim newForm As New Form1
        forms.Add(newForm)
        newForm.Show()

4, Finally in the "Home" button's click event on the child form, add the following:

VB Code:

Dim frm As Form
        For Each frm In forms
            frm.Close()
        Next
        forms = Nothing
        forms = New FormsCollection

It's a bit rough and ready as far as coding goes, but it should get you started... :afrog:

Hi,

I'm a bit dumb on this type of approach so I'm probably missing something but doesn't that code simply create several instances of the same form?

If it does create instances of different forms, how do you refer to each form if you want to access it from another?

This code was taken from a forms collection that I use to create multiple instances of a form. For example, the application allows several customer records to be opened at once, but only one instance of every customer. So the full version has a method that allows you to check the object stored in each form's tag property.

When I open a customer record, I store the datarow from the dataset (or you could store just the customer's id) in the tag property. Then, I have a method in the forms collection called IsInstanceInCollection which goes something like this:

VB Code:

Public Function IsInstanceInCollection(ByVal formName As String, ByVal row As DataRow) As Form
        Dim item As Form
        Dim formRow As DataRow
        Dim counter As Integer
        Try
            'loop through the forms collection
            For Each item In list
                If item.Name.ToLower = formName.ToLower Then
                    'if the form names match then retrieve the row
                    formRow = CType(item.Tag, DataRow)
                    'if the items in the left most columns match then return the form as the correct item
                    If formRow(0) = row(0) Then
                        Return item
                    End If
                End If
            Next
        Catch ex As Exception
            MessageBox.Show("Error locating the specified instance of " & formName)
            Return Nothing
        Finally
            formRow = Nothing
            item = Nothing
        End Try
    End Function

This returns the instance of the form if found.

The calling code is an If statement that checks to see if the method returns something and if not, will create a new instance to display to the user and stores the relevant data row in the tag property as the new form is loaded.

It is overloaded to work in a variety of different ways.

A cut down version of this to work with the code that staticbob wrote would go something like this:

VB Code:

Public Sub Remove(ByVal formTagObject As Object)
        Dim frm As Form
        For Each frm In MyBase.InnerList
            If frm.Tag = formTagObject Then
                MyBase.InnerList.Remove(frm)
                Exit For
            End If
        Next
    End Sub

To use this, I just created a unique string to store in each new form's tag object when instantiating and adding them to the collection.

Hope this clarifies things :D

Hi,

Thanks, that's what I thought. But this guy wants to open one instance each of several different forms.

Hi staticbob,

What you have to do depends on how you start your programme. Please confirm or deny the following: (I am using the word "Open" loosely, in it's VB6 sense. meaning that whilst Open an instance of a form is still available even though hidden)

1. HomePage is the Startup form or

2. A. You start from the Module Sub Main
B. You want HomePage to remain open throughout the programme
(although you may want it hidden or behind the other forms) - this is
normal except for splash type forms.

3. You want your other forms to be opened from HomePage and sometimes to
remain open when the focus moves to HomePage but at other times to
close.

4. You sometimes want to close all open other forms and leave only
HomePage open.

I am going out for the rest of the day so I will not be able to reply quickly. Others might.

Best of luck.

The other thing I noticed from the original post is that it's using ShowDialog which won't work by launching multiple forms from the home page. I would imagine you are using Show Staticbob?

Quote:

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Originally Posted by Lil Ms Squirrel

The other thing I noticed from the original post is that it's using ShowDialog which won't work by launching multiple forms from the home page. I would imagine you are using Show Staticbob?

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It depends what he wants to do. Yes, he will have to close them but he can still keep the instance if he wants to, ready to show again.