I've created a customized collection and want to databind it to a DataGridView. After some research, I found that I need to create a bindingsource control and then bind to the specific collection object.
The first problem is that I need to retrieve the collection instance for some additional method calls. How can I get the underlying collection instance back I found that the databingsource will use BindingList<T> as its internal store. How can I convert it back to my specific collection so that I can make additional method call
Databind to collection object
John Winstanley
as I am not sure what Total is based on. . . I will assume FooBar has a double property: Value. . .
Public Class FoobarCollection
Inherits BindingList(Of FooBar)
'' define your methods here if they
'' aren't already handled via the
'' generic mechanism
Public ReadOnly Property Total as Double
Get
Dim temp as Double = 0
For Each foo as Foobar in Me
temp += foo.Value
Next
Return temp
End Get
End Property
End Class
Saurabh Dhall
ok. . . I made this. . .
Colin Doran
The message box just have showed runtimetype.
BerndMei
Return to my first question, how can I retrieve this collection from the databindingsouce so that I can get this property I've tried something like this.
Dim lTenderItemCollection As TenderItemCollection = CType(Me.TenderItemsListBindingSource.DataSource, TenderItemCollection)
Me.paidTotalTextBox.Text = lTenderItemCollection.GetPaidTotal
This doesn't work as the CType has failed to make the cast.
JohnInTampa
what does this code show you. . .
MessageBox.Show(Me.TenderItemsListBindingSource.DataSource.GetType().Name)
Pat84
public class FoobarCollection
inherits BindingList(Of FooBar)
'' define your methods here if they
'' aren't already handled via the
'' generic mechanism
end class
[notice how much cleaner the c# is ]
B.H.V.Ramakrishna
Pete Bennett
Belair, thanks for your help first. Actually, I've just made the same thing worked. (Certainly with your help) However, referring to the first message, I'm actually working on a DataBindingSource. The databindingsource use the TenderItemCollection object as the datasource. The DataBindingSource will create an instance by itself. The code that you show is putting an instance into the DataBindingSource instead of the self-gerenrated one. I hope that you understand the difference that I want to point out.
If I use the above coding, actually I don't need to get the TenderItemCollection out from the DataGridView. Instead I can use the bl directly.
The reason that I would like to do this because it'll be easier to configure the DataGridView's columns if the DataBindingSource is configured with a datasource.
Lyndon J Clarke
Taby
your custom collection should inherit from BindingList. . .
if you have a class FooBar. . . and a collection FooBarCollection
change the declaration for FoobarCollection to
fastcarrera
Jason Browne
Thanks for your advise first. I can't make the above code work at first because I've not added the namespace System.ComponentModel. After I import it, the above syntax works.
As I need to write a function that calculate the total stored in each item, so is there any way to do so I found that there's a property called Items. I hope it's what I need.
Another question is how can I get back this list from databindingsource and call the function that I need
Thanks Blair!
Alex_M
JaLeo