Listview refresh

[durilai]

I have a simple form that has a listview that is populated by a table in access. There is a button that opens another form using showdialog so that the first form stays in the background. The second form is used to add a value to that same access table. When I click the add button I want the value to be added, the current form to close and the new value to show in the listview. Everything works except the new value does not show, if I stop and then start the project the value appears. So I just need to refresh the listview which is being populated on formload. I have tried to use the refresh and update command, but to no avail. Any help is greatly appreciated.

 

Thanks

[Diesel]

You have to repopulate the listview...or just add the new item to the end (if it's not sorted or you don't care)

 

Put the code you use to populate it in a seperate function and call it when it needs to be refreshed, but add

 

listview.Items.Clear()

 

as the first line in the new function.

 

And call that function at load

[durilai]

I have tried that. The problem is that its on a second form and the listview is populated on the first form's form load, so clearing the listview does no good. I need a way to reload the form with out creating a new instance of it. Or a better method, but I am just trying to accomplish four things.

 

1. View an access table

2. Add a Record to an access table

3. Refresh the list

4. Pass a value to a seperate form

 

I am able to view, and update the table. I am now trying to refresh the list, and pass the value.

 

Thanks for your help.

[Diesel]

The problem is that its on a second form and the listview is populated on the first form's form load, so clearing the listview does no good.

 

The listview should be populated by it's own container.

 

And no matter what, if you reload the listview after a new record is added or deleted, it will show the new/deleted record!

[durilai]

This is what I have:

 

#Region " .... Fetch data .... "

Private Sub fetching()

Me.ListView1.Items.Clear()

Try

 

strSQL = "SELECT * FROM class"

cmd = New OleDbCommand(strSQL, oledbcon)

objRead = cmd.ExecuteReader

While objRead.Read

lvItem = Me.ListView1.Items.Add(objRead("ClassID") & "")

lvItem.SubItems.Add(objRead("ClassDescription") & "")

lvItem.SubItems.Add(objRead("ClassDate") & "")

End While

Catch ex As Exception

MessageBox.Show(ex.Message)

End Try

End Sub

#End Region

 

#Region " .... load event .... "

Private Sub frmClass_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

 

End Sub

#End Region

 

Private Sub ListView1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ListView1.SelectedIndexChanged

oledbcon.Open()

fetching()

oledbcon.Close()

End Sub

 

If I place the db open, fetch, dbclose items to the form load area then it populates the listview automatically, but as it is there nothing happens

[Diesel]

You are reloading the listview on the wrong event.

If you reload the listview on the selectedindexchanged event, everytime the user selects a new row the listview will be reloaded.

 

If right now all you are doing is adding a record the database, you need to send an event to this form when a record is successfully added to the database.

 

Take a look at my other post to add the event.

 

Also, you might want to fix up your 'fetching' code...

 

Get rid of the class variables...except for oledbcon

 

 

 Private Sub LoadClasses()
       Me.ListView1.Items.Clear()

       Dim command As OleDbCommand
       Dim reader As OleDbDataReader

       Try
           oledbcon.Open()
           command = New OleDbCommand("SELECT * FROM class", oledbcon)
           reader = command.ExecuteReader(CommandBehavior.CloseConnection)

           While reader.Read()
               Dim lvItem As New ListViewItem(reader("ClassID").ToString())
               lvItem.SubItems.Add(reader("ClassDescription"))
               lvItem.SubItems.Add(reader("ClassDate"))
               Me.ListView1.Items.Add(lvItem)
           End While
       Catch ex As OleDbException
           MessageBox.Show(ex.Message)
       End Try

       reader.Close()
   End Sub

#End Region

#Region " .... load event .... "
   Private Sub frmClass_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
       Me.LoadClasses()
   End Sub
#End Region

 

Call LoadClasses in Form_Load and get rid of the SelectedIndexChanged Event.

 

And Again, add an event to the form that adds records to the database, handle the event in the parent form. Have the parent form call LoadClasses to refresh the listview.

[durilai]

I replaced what you popsted and I get an error on this line

 

lvItem.SubItems.Add(reader("ClassDate"))

 

with this error

 

An unhandled exception of type 'System.Reflection.AmbiguousMatchException' occurred in microsoft.visualbasic.dll

 

Additional information: No accessible overloaded 'ListViewSubItemCollection.Add' can be called without a narrowing conversion.

[Diesel]

lvItem.SubItems.Add(reader("ClassDate").ToString())