I am using a ComboBox tied to a BindingSource.
After selecting the appropriate choice, I need a bunch of things to happen, but the BindingSource needs to be up to date first, in other words the current record needs to be fully loaded before continuing.
I am currently using the DropDownClosed event, but other TextBoxes bound to the same binding source haven't updated yet. Is there another event I can use?
Related
I have a combobox that is populated by a database table I have. In my Load event for my form I have it populated by...
Me.BusinessTableAdapter.Fill(Me.BillingdbDataSet.Business)
My problem is whenever I "add", "edit", or "delete" a business I have stored I can't find a way to update the combobox I have. Whenever I exit and reopen my program and I can see the changes but was hoping someone could inform me on how to have it updated after a change has happened.
The problem is you need something that implements INotifyCollectionChanged.
MSDN
You can enumerate over any collection
that implements the IEnumerable
interface. However, to set up dynamic
bindings so that insertions or
deletions in the collection update the
UI automatically, the collection must
implement the INotifyCollectionChanged
interface. This interface exposes the
CollectionChanged event, an event that
should be raised whenever the
underlying collection changes.
You can refresh it manually, but the ideal situation is the bind to an observable collection class - http://msdn.microsoft.com/en-us/library/ms668604.aspx HTH
Wade
If you're using datasets you can use the dataview class which raises events when the underlying dataset is changed. Then you could either look into data binding them to the combo-box or write your own update code and put that in an event handler for the event raised when the list changes.
I have a List of an object, set to DataSource of a BindingSource, set to DataSource of a DataGridView. Then I added a DataGridViewButtonColumn which I want a click to remove that record from the collection. So I simply call collection.RemoveAt(e.rowIndex) from the DataGridView CellClick event. However this produces an IndexOutOfRange Exception; "1 does not have a value"..
So is happening here? I have maybe a vague idea, but would like to understand exactly which events are failing etc.. and what do i need to do to perform this action properly?
EDIT:
This seems not to happen if I use a BindingList.. But when using a List, I get this problem..
The reason you're seeing the error is because you're ultimately binding to a List. List doesn't include the notifications of changes that your DataGridView needs to receive to reflect the changes you make.
If you really want to work around this you could do the following: just before you make a changes to your List, set the BindingSource's DataSource property to Nothing. When you're done making changes reset your List to the DataSource.
This is a pretty ugly solution as you can imagine. What you'll want to do this bind to an object that implements IBindingList, either a custom collection you create or a BindingList.
Here's a reasonable starting point for investigating this further:
DataGridView Control Overview (Windows Forms)
I have a combobox where the SelectedValue on the combo is bound to a property on a business object.
Everything works fine, but the property that's bound to the SelectedValue on the combo only gets updated when the focus leaves the control. I understand that the property doesn't get updated until the control is validated (loses focus), but I need it to update the datasource as soon as the dropdown is closed.
I know I could probably leave focus from the control on the DropDownClosed event but I'd prefer something a little less kludgy.
What's the best way to immediately update my datasource when the dropdown is closed?
Set the DataSourceUpdateMode to OnPropertyChanged. Here is similar problem:
[http://social.msdn.microsoft.com/Forums/en/winformsdatacontrols/thread/bc39342b-d9b5-4ad0-bd35-073869ccf8be][1]
The way I'd do it is to set (in the events) the OnUpdate of the combo box and put in the VB.net
Me.<business object>.Requery
I am trying to hide specific columns in an Access 2007 split form through code. I need the form to check certain conditions to see whether it needs to display a column or not. I have code in the form's 'Activate' event to hide the column like this:
txtControl.ColumnHidden = True
This code works in the "Open" event, but if I hide the column on Activate, it won't display these changes until I close the form and open it again. I have tried calling the form's refresh, repaint, and requery methods, but this doesn't work. Please help!
Edit: Ideally, I need this event to occur whenever the focus switches to this form.That's why I'm using the Activate event rather than the Open event.
Try setting it in either the form's Current or Load events. You will also probably need to requery the control after setting that property: Me.TextControl.Requery Current is called every time a form's record is changed, the form is repainted or requeried. Load, as its name suggests, is called once, after the form has opened when the form loads its records. These have always been more reliable for me than using Activate, which really has to do with more the focus of the form, not really what you want.
I've had a problem like this before working in Access 2002. I was able to solve the problem with a subform by setting the subform source object equal to itself and then running the requery.
Me.SubForm.SourceObject = Me.SubForm.SourceObject
Me.SubForm.Requery
See if this technique works for your particular situation.
VB 2008 .NET 3.5
I have a custom "Shipment" object that contains a list of "ShippingRate" objects. This list of "ShippingRates" is accessible through a property "Shipment.PossibleShippingRates." That property simply returns a copy of the list of "ShippingRate" for that particular Shipment.
My UI layer receives a list of "Shipment" objects from the BLL. This list is databound to a datagridview, and shows details relevant to the Shipment such as Shipping Address, etc.
I want to bind the "Shipment.PossibleShippingRates" property to a combobox, such that when the user changes the grid row, the combobox reflects the "PossibleShippingRates" for that "Shipment."
In addition, I need a way to store the "ShippingRate" they selected from the combobox for later use.
I have tried a few ideas, but none of them work properly. Any ideas on how to do this?
Wouldn't the simplest solution be to tie a TextChanged or SelectedIndexChanged event to any/all fields in the datagrid that need to trigger a refresh of the combobox?