I want to be able to reorder my listbox which is bound to my sql ce database by clicking up and down arrow buttons. Since my listbox is populated directly from my database using the entity framework, I think I have to delete the object (from the listbox) and reinsert it (in the row above) if I want to move the item up the list.
I have no view model, my listbox is populated directly from my database in my code like this:
listBoxProperties.ItemsSource = entities.Properties.ToList();
Does my question make sense?
Cheers
ormally you would handle the moving of your list item in your view model which would hold the ObservableCollection the control was bound to - and then that would be reflected in your control via the binding.
It is going to get messy trying to accomplish this dirrectly on the control - which is your only way since your binding to a throwaway copy of the EF properties list.
As your UI dev goes on you are only going to run into more issues like this. I strongly recommend getting a view model in place sooner rather that later.
Related
Im in the process over converting some legacy VB6 code over, in particular a TDBGrid linked to an ADODC data control.
Everything is going ok, ive got my columns and bindignsource reading sweet as a nut and performing what its supposed to do, correctly - but im having a problem converting this type of method over.
In the vb6 app, while a user scrolls through the grid, the grid fetchstyle (similar to cellformatting) go looking at the equivalent row of data in the adodc.
In .net, I cant seem to get that functionality to be the same, unless I add that field from the database, into a column in the grid and make it invisible (which I dont really want to be doing if i can help it) then read the cell via cellformatting and then perform some action, such as changing the cellstyle backcolor to something.
Is it possible to refer to a row in the bindingsource that would be the same row in the grid that a user is at, without having that field from the bindingsource - in a DGV column?
or do i just have to put up with placing more columns in the DGV than I want and just live with it?
Thanks!
I think you want the BindingSource.Current
object.
I am just getting started with obj-c programming and cocoa.
Here is what I am trying to accomplish and have gotten stumped on.
I have a single table view of managed objects in Window1. I have a "Add Items" button that calls Window2 that has another blank table view (AddItemsTableView) and a series of form fields a user could fill in.
When a user fills in these fields and clicks an add button in Window2, the string values of said fields are input into AddItemsTableView to show a running list of items they are preparing to add. When the finally commit the add, I would like that running list to instantiate as NSManagedObjects
Do I need to do this as a seperate entity within coredata created just for objects to be added, then transfer the objects to the new entity upon the add action? Do I need to save them in a mutable dictionary and convert the dictionary to managed objects?
It's important that the addItemsTableView only contains data for the time period the window is open. When Add is commmited, the window closes and the table bound to the core data entity in Window1 updates with new results. If Add Items in Window 1 is pressed again, Window2 is called with an empty tableview again.
I've been searching through SO and other forums for days trying to find someone attempting to do the same thing. Can anyone point me in the right direction?
Thank you so much!
Connect your add table view to the original table view via a delegate #protocol so it can inform the other on its state and enable it to react accordingly.
Of course you use the same type of managed object throughout, no interim objects such as dictionaries. When the added data is saved, you could send the object back to the original table to be processed.
(Alternatively you can save and rely on e.g. the fetched results controller delegate - but maybe that is too advanced at this stage.)
I am new to Visual Basic and trying to get around in developing a good gui for a chat interface. I can understand the language as i have been using php and java from quite sometime.
Requirement
Basically i am trying to develop a interface which will show a list of users and along with that display a status (online/offline). My users will reside in mysql database. On clicking the user i want some actions to happen.
Question
I see there is datagrid, listview,listbox but not sure which one to use. Also is it a good idea to display the users by directly quering the mysql database or by accessing a php script which runs few queries and gives the data?
The ListBox control would not be a great option since it doesn't easily support multiple columns. The ListView control in Details view is a great option. I think it looks and works nicer than a DataGrid, but it doesn't natively support multi-line items. If you need multi-line items, the DataGrid control may be your best choice. Another option, which would give you more flexibility, would be to use a LayoutPanel control to display a vertical list of your own UserControl. You could design the UserControl anyway you want meaning you could fully control the size, look, and layout of each item in the list without being constrained by the list control.
As far as getting the data, that depends. If the database is always on the LAN and performance is important, then each client should go directly to the database. Otherwise, getting the data from a php script, web service, or WCF service would be a much better choice.
Rather than using the TableLayoutPanel, I would recommend using the FlowLayoutPanel with the FlowDirection property to TopDown and the AutoScroll property set to True. Then, to add a control dynamically, you could do something like this:
Dim item As New MyUserControl()
' Set properties of user control
FlowLayouPanel1.Controls.Add(item)
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)
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?