Update Controls .NET VBC#

UpdateListView

A list view that automatically updates its data.

To use a list view, first set up the properties. You probably want to set View to Details, and add Columns. It is also is useful to set HideSelection to false.

Now choose a data type for the items in the list. This is your own type, not a special row, and it does not implement a predefined inerface. It should probably be the data type you use for all your business logic. If it implements ToString, text will be automatically displayed. If not, don't worry; you will just have to implement one more event.

The first event to implement is GetItems. Return a collection of your objects. Then if your class doesn't implement ToString (or if you want different text to appear), implement GetItemText. This text is used for the first column of the detail view; for the other columns implement GetSubItems. Return a collection of strings to display in the remaining columns.

Selection in the list view typically represents UI state, not data. You can access the collection of objects that the user has selected with the SelectedItems property.

But sometimes list selection represents data. You might have a collection in your data set that represents a subset of the items in the list, and you want selection to reflect this subset. For better usability, I'd recommend setting the CheckBoxes property and using the GetItemChecked and SetItemChecked events for this. But if it has to be selection, then just implement the GetItemSelected and SetItemSelected events.

Example:

Return the business objects to display in the list from GetItems.

Private Function personListView_GetItems() As System.Collections.IEnumerable
	' Return all person objects.
	Return _document.People
End Function

Private Function personListView_GetItemText(ByVal tag As Object) As String
	' We know that the tag is a person,
	' since it was returned from GetItems.
	Dim person As Person = DirectCast(tag, Person)
	' Display last name, first name in the first column
	Return person.LastFirst
End Function

Private Function personListView_GetSubItems(ByVal tag As Object) As System.Collections.IEnumerable
	' Display age and occupation in the second and third column.
	Dim person As Person = DirectCast(tag, Person)
	Dim subItems as New List
	subItems.Add(person.Age)
	subItems.Add(person.Occupation)
	Return subItems
End Function

Private Function ButtonEnabled() As Boolean
	' The edit and delete buttons are enabled when a person is selected.
	Return personListView.SelectedItems.Count > 0
End Function

Private Sub addButton_Click(ByVal sender As Object, ByVal e As EventArgs)
	' Create the new person object.
	Dim person As Person = _document.NewPerson()
	' Select the new person object.
	personListView.SelectItem(person)
End Sub

Private Sub editButton_Click(ByVal sender As Object, ByVal e As EventArgs)
	' Open each selected person.
	For Each person As Person In personListView.SelectedItems
		EditPerson(person)
	Next
End Sub

Private Sub deleteButton_Click(ByVal sender As Object, ByVal e As EventArgs)
	' Delete each selected person.
	For Each person As Person In personListView.SelectedItems
		_document.DeletePerson(person)
	Next
End Sub

Constructors:

Properties:

Methods:

Events: