I haven't been able to successfully bind some test data to a SketchFlow ComboBox. I added a sample data source and created a collection with some basic string values. There are a number of tutorials on how to bind to a ListBox in SketchFlow and that works fine, just not finding anything for a ComboBox.
One thing that caught me out a few times is that you need to have your data in "list mode" before you drag it on to the control (combo box or list box).
It seems to work as I expected, so perhaps I'm not understanding your issue correctly, but I'll give it a shot! I created a sample DataSource with a couple of strings in it, added a ComboBox to the layout root and then just dragged the Collection from the DataSource and dropped it on the ComboBox.
Keep in mind that if you drag the DataSource itself, you'll only be setting the DataContext property of the ComboBox and that's not enough to get your items to display. You also need the ItemsSource bound to the Collection of the DataSource and an ItemTemplate or a DisplayMemberPath to tell the ComboBox how to display your items.
Additionally, if you use the drag and drop method of binding, it will use the ItemTemplate approach for you, which may or may not be what you want as it will generally create a StackPanel and display all fields from the row in your Collection per item in the ComboBox. You can remove the ItemTemplate and set DisplayMemberPath to whichever field you wish to have displayed from your data source's collection.
Related
I want to have in my gwt application a ListBox with a watermark.
I already created TextBox and a DateBox with a watermark by extending those classes and the property placeholder of the DOM.
However I could not such property for the ListBox. There isn't any, right? (how can I tell? except for trying.)
Assuming that there is no such property I would like to implement such a class by extending ListBox.
I am not sure how such a ListBox would behave.
could you please help me define the behaviour of such ListBox or maybe you know a site that uses one so I could play with it? Or just point me to a code example.
Thanks
I would think it would be a non editable list item as the placeholder. You could have the setPlaceholder set the text on the list item. The placeholder list item would only be visible when the list was empty. You couldn't select the list item, and all methods to access list items would never see it.
I have a view with a list box, bound to am obvervable collection of DisplayItems, which has 'Label', 'DisplayValue' and 'IconUri' properties.
I have a View Model which exposes this observable collection. The List Box is correctly populated first time around.
I then have a button which takes action on the selected item. I need to indicate that action has been taken by changing the image.
I am changing the IconUri of the selected item, and can see the new value present when debugging, but the image doesn't change. I can also change the 'Label' and 'DisplayValue' properties and see the new values correctly there when debugging, but the list doesn't change.
My ViewModel implements INotifyPropertyChanged. My DisplayItem class implements INotifyPropertyChanged. I'm calling RaisePropertyChanged I'm sure in too many places rather than too few.
None of the changes are ever reflected on screen.
I'm using a DataItemTemplate for the generated rows. If I could access the image of the selected row I could change it manually, but I can't even do that.
Any help greatly appreciated. I could actually do with a example of a list box displaying items from a bound observable collection, where one property of the selected item is changed and that change is reflected in the list box.
Thanks in advance
A
You didn't implement INotifyPropertyChanged correctly, or you're using it wrong.
I have a View that contains a Listbox. I'll call it CityListingPage.xaml. This list page has a CityListingViewModel, that is binded with the View like somewhat like this:
DataContext="{Binding CityListing, Source={StaticResource Locator}}"
This works nicely. Now I what to change my page to a Pivot Control, where the Pivot Items, would be instances of CityListingViewModel, but obviously with different constructor data (ie. Country)
I extracted the ListBox into a UserControl. Now I'm struggling how to make this work so that for each list I get a new instance of the CityListingViewModel.
I tried creating in the ViewModelLocator a collection of CityListingViewModels but how do I pass the a CityListingViewModel instance to the UserControls DataContext?
Perhaps there is a different, better way of doing this?
Without seeing your code, I'm going to do a little guessing, but I think you can do it directly via data binding. Since each pivot item is getting an instance of CityListingViewModel, you can just pass that binding along to the UserControl:
If you post a little more code showing what you're trying to do, we might be able to be of more help.
The following are two answers for using a collection to create panorama pages. But I am quite sure that the approach can be adapted to pivot pages:
Dynamically add eventtocommand actions to a listbox
Static and dynamic panorama items in a panorama wp7 mvvm
The second post should be more relevant.
If you are thinking of partitioning the same data over multiple views on a pivot page then I would suggest NOT using several view models, especially if it is the same datasource you are using for all the data.
Simply have a parameter which each view would bind to and use Linq to control what data is visible to that parameter.
So you will have the variable which will contain all the data to be displayed and one parameter per view querying that data.
I have a datagridview on a windows form. It has clolumn [EmployeeNumber, EmployeeName and EmployeeDepartment].
I want to be able to edit values directly in the grid but i want EmployeeDepartment to be a combobox column, such that on cell edit, a combobox shows up with available options for the employee department. Has any one been able to implement such functionality?
The DataGridView actually has a DataGridViewComboBoxColumn. If you go to the column designer, and add a new column you'll notice you can select one of a few types. It behaves exactly as you have described - on edit, it appears. The DataGridView uses things called editing controls, and has various events for swapping the control into the cell on edit.
Either way, if all you want is a drop-down, that's available out of the box.
To populate the combo box with items, in the column editor you will notice that it has an Items property for manually setting items, or you can use the data binding properties: DataSource, DisplayMember, ValueMember. Data-binding has issues when an expected value is not in the items collection, you will get a lot of cell errors; but they can be avoided.
Some helpful links:
http://msdn.microsoft.com/en-us/library/system.windows.forms.datagridviewcomboboxcolumn.aspx
http://social.msdn.microsoft.com/forums/en-US/csharpgeneral/thread/e8e2d9eb-fe39-42ab-9a18-2194dac54675/
I've got a table one column of which uses an NSPopUpButtonCell. Try as I might, I can't seem to figure out the way to properly bind everything the way I want it. Here's what I'm trying to do:
I have an NSArrayController plucking items from a managed object context, called 'Field Values'. This is to be used to populate the popup menu for each item (i.e. the list of available choices). I can bind this by selecting the cell in IB and binding its content/objects/values to 'Field Values'.arrangedObjects and 'Field Values'.arrangedObjects.name as appropriate (to get the represented object and the visible title).
I then want to bind the column in such a way that the selected value in each row comes from an array in my controller class, again made visible (and only edited through) another NSArrayController.
So far I've managed to set it up so that every popup menu contains the list of available fields, and that the default value is selected in each of them. Actually selecting an item has no effect, however— it just snaps back to its initial value. I've also managed to find some other variations on this, such as the menu being populated with the selected values, or containing the name of all available values, and the selection containing the -description of the 'none' value I added.
I'm sure I'm missing something fairly simple, but I'm not sure what it is. Presumably there's some subtlety I've missed in how to bind this sort of data (i.e. the Content vs. Content Object vs. Content Value things), but I'm damned if I can see it right now.
Many thanks in advance :o)
I've got a similar set up with a table view, although the data source isn't Core Data based, but I saw one thing you might double check that could be a subtle difference. In my setup for the table column, I have the table column itself bound via content, contentValues, and selectedObject. However, it looks like it's also possible to do the bindings on the actual NSPopUpButtonCell instead. Perhaps it works when the bindings are on the table column, but not when they're on the actual cell? Anyway, there's one thing that might be worth looking into.
Never bind to scroll view, table view or cell.
However, ever bind to table columns.
Watch the title of the Inspector window to be certain of what you're binding.