I have a whole bunch of code that is dependent on the ComboBox type, and I want to be able to use it on a new UI, but the UI that I want to use it for needs to look like a RadioButton for usability reasons. Is it possible to have a ComboBox control look like a set of RadioButtons?
My suggestion would be to use an ItemsControl with a DataTemplate that would render RadioButtons. To the ItemsControl you'd bind the same thing you're binding to the ComboBox.
One caveat is that you need to set the GroupName of the radio buttons to something that would be the same to the group, so they can be mutually exclusive. Otherwise, if you don't do anything, you'll be able to select more than one RadioButton simultaneously.
You could build a new UserControl that has many of the same methods that the ComboBox class does, but adapt it so that it creates multiple radio boxes instead.
Your question is kinda vague though.
IE create an Items collection on your user control, and when something is added, draw a radio box and resize your control, instead of what a combo box does and just adds a string to the list.
Then all you have to do is find and replace all your references to ComboBox with RadioIFiedComboBox.
Heres some comparison:
ComboBox cb = new ComboBox();
cb.Items.Add("blah");
or
RadioIFiedComboBox cb = new RadioIFiedComboBox();
cb.Items.Add("blah");
and
public class RadioIFiedComboBox : UserControl {
public ObservableCollection<object> Items = new ObservableCollection<object>();
public RadioIFiedComboBox() {
Items.CollectionChanged += new NotifyCollectionChangedEventHandler(YourCollectionChanged);
}
private void YourCollectionChanged(){
//do something here to redraw your controls
}
}
The code above is just an example, you'd have to create all the methods you use in the ComboBox class and create similar functionality.
Related
How can I get multiple instances of a usercontrol without the viewmodel being shared? Each usercontrol (and thus viewmodel) should be an instance of its own.
I have read a solution in this question: MVVMLight UserControl View Model-Create new Instance of User control for each view but I cannot get it to work!
I have a listview and a tabcontrol. When I click an item of the listview a new tab must be created with as content the usercontrol which holds information from the selected listitem. The problem is that when selecting multiple items all the items contain the information from the last selected item.
This is my viewmodellocator:
public DossierDetailViewModel DossierDetail
{
get
{
return new DossierDetailViewModel();
}
}
And I call the new usercontrol like this:
DossierDetailViewModel newDossier = new DossierDetailViewModel();
newDossier.TabName = SelectedDossier.Omschrijving;
this.OpenDossiers.Add(newDossier);
Messenger.Default.Send<DTO.Dossier.Dossier>(SelectedDossier, "SetDossier");
EDIT:
Is there no one who can help me or put me in the right direction? :(
The answer of this problem can be found here: https://mvvmlight.codeplex.com/discussions/577555
I have all the styling, triggers, etc. down for ListView and ListViewItem, and I want to turn them into user controls. How do I make sure that these two "match up" with each other, so that MyListView accepts MyListViewItems as content? Also, considering that I must end the ListView tag by the end of the user control XAML file, I am not sure how I would add items to it.
If you want them to be reusable with different data sets, especially through binding, you should stay away from UserControls and just make custom controls derived from the original types. In that case you create a standalone MyListView.cs and MyListViewItem.cs and all of the XAML for the controls goes into default Styles (usually also containing a ControlTemplate) in Themes/Generic.xaml. You can see an example of this setup by just adding a WPF Custom Control to your WPF project from Add New Item.
Once you've created the .cs files for your custom controls you just need to override a few methods from the base ItemsControl to use MyListViewItem as the item container control. The ListView would end up like this:
public class MyListView : ListView
{
static MyListView()
{
DefaultStyleKeyProperty.OverrideMetadata(typeof(MyListView), new FrameworkPropertyMetadata(typeof(MyListView)));
}
protected override DependencyObject GetContainerForItemOverride()
{
return new MyListViewItem();
}
protected override bool IsItemItsOwnContainerOverride(object item)
{
return item is MyListViewItem;
}
}
You can now use your custom MyListView exactly as you would a normal ListView, including binding to ItemsSource.
Inheritance should take care of that for you. In other words, if you have two user controls, the first one with a basic element of ListView (not UserControl) and the other of ListViewItem (again, not UserControl), and you make sure they extend ListView and ListViewItem respectively in the .cs code, the following should work equally:
ListView lv = new ListView();
lv.Items.Add(new ListViewItem());
or
MyListView mlv = new MyListView();
mlv.Items.Add(new myListViewItem()); //If your myListView extends ListView, and myListViewItem extends ListViewItem in your user control files, of course
In case you are looking for a XAML solution, you should import your namespace at the top
xmlns:myControls="WhateverYourNamespaceAndAssemblyAre"
and on you page/window/whatever
<myControls:myListView>
<myControls:myListViewItem/>
<myControls:myListViewItem/>
</myControls:myListView>
When my combobox expands and I select an item, I want the combobox to change visual state(it is highlighted). This will signify something is selected. I tried various VisualStates but none of them would trigger in this scenario. How can I achieve this? Thanks.
The standard ComboBox simply doesn't have states to distinguish between having something selected and having nothing selected.
There are a number of ways to go about solving the underlying problem, and it depends mostly on the answer to the following question:
Do you really need to change the visual appearance of the ComboBox itself or does it suffice to style the selected item more prominently?
If it's the latter, you're best served with the rather easy way of using a custom control template for the ComboBoxItems.
If you really want to style the ComboBox itself that way, there are two options I can think of:
A) Add custom states to a ComboBox with a custom template.
Copy your ComboBox's control template and add another state group to the already present states. Both of this is typically done in Expression Blend.
After that you can update the new states in code with
VisualStateManager.GoToState(this, "Selected", true);
for example. You will have to set those states yourself when the first item is chosen. This could be done on the SelectionChanged event.
B) Derive from ComboBox
If you want to use the control in this way often, it might be worthwhile to derive from ComboBox to make your own custom control.
It would look somthing like this:
[TemplateVisualState(Name = "SelectedStates", GroupName = "Unselected")]
[TemplateVisualState(Name = "SelectedStates", GroupName = "Selected")]
// ... (more attributes copied from the ComboBox ones)
public class MyComboBox : ComboBox
{
public MyComboBox()
{
SelectionChanged += HandleSelectionChanged;
DefaultStyleKey = typeof(MyComboBox);
}
void HandleSelectionChanged(object sender, SelectionChangedEventArgs e)
{
VisualStateManager.GoToState(this, SelectedItem != null ? "Selected" : "Unselected", true);
}
}
And you would then need a default style based on the default ComboBox style (or whatever you usually use).
Note that I didn't test this in any way.
I have a little trouble with INotifyPropertyChanged. I implemented it lots of times, however this case is different. I would like to create the following application:
There are multiple tab containers, which are bound to different ObservableCollections of Entities. Now I would like to show the name of the currently (last) selected Entity. To achieve this, I've created created a DependencyProperty CurrentEntity in the Window class and assign via SelectionChanged on the TabControls the current Entity.
private void SelectionChanged(Object sender, EventArgs e)
{
CurrentEntity = e.NewItems[0] as Entity;
}
The TextBlock which, in the above picture, displays VideoA looks like this:
<TextBlock Text={Binding CurrentEntity.Name}" />
Now whenever I select a new Tab, the Text in the TextBlock changes accordingly. However when I change the the name of an Entity (inside a TextBox in a Tab, which is also bound to the Entity), the text in the TextBlock doesn't change. I have to select another Tab and then change back to the Tab where I changed the Name to see the newly entered name in the TextBlock. Basically, this is my problem, I would like to see the text changing without selecting another Tab first (and yes, I de-focused from the TextBox inside the Tab after entering the new Name).
Has anyone an idea where the problem is?
My "architecture" looks (more or less ;-)) like this:
ObservableCollection just means that the event to update UI is kicked off when the collection changes, you add, remove, re-order, etc.
Altering an the property of an item in an ObservableCollection, such as a string, doesn't not actually cause a UI event.
Does the object you have inside the ObservableCollection implement INotifyPropertyChanged?
I have Window that has a ListBox
ListBox(MyListBox) has a DataTable for its DataContext
ListBox's ItemSource is : {Binding}
Listbox has a UserControl(MyUserControl) as DataTemplate
UserControl has RadioButtons and TextBoxes (At first They're filled with values from DataTable and then user can change them)
Window has one Submit Button
What I want to do is, when user clicks the submit button
For each ListBox Item, get the values form UserControl's TextBoxes and RadioButtons.
I was using that method for this job :
foreach(var element in MyListBox.Items)
{
var border = MyListBox.ItemContainerGenerator.ContainerFromItem(element)as FrameworkElement;
MyUserControl currentControl = VisualTreeHelper.GetChild(VisualTreeHelper.GetChild(VisualTreeHelper.GetChild(myBorder,0) as Border,0)as ContentPresenter,0)as MyUserControl;
//And use currentControl
}
I realised nothing when using 3-5 items in Listbox. But when I used much more items, I saw that "var border" gets "null" after some elements looped in foreach function.
I found the reason here :
ListView.ItemContainerGenerator.ContainerFromItem(item) return null after 20 items
So what can I do now? I want to access all items and get their values sitting on user controls.
Thanks
You should use objects who implement INotifyPropertyChanged and bind an ObservableCollection of it to the ItemSource
And then you can get all the list of items.
Here some quick links from MSDN to get more informations
How to: Implement Property Change Notification
Binding Sources Overview
You should google for some tutorials about this.
Zied's post is a solution for this problem. But I did the following for my project:
I realised that there's no need to use UserControl as DataTemplate in my project. So I removed ListBox's DataTemplate.
I removed MyListBox.DataContext = myDataTable and used this:
foreach(DataRow dr in myDataTable.Rows)
{
MyUserControl muc = new MyUserControl(dr);
myListBox.Items.Add(muc);
}
I took DataRow in my UserControl's constructor and did what I want.
And at last I could access my UserControls in ListBox by using :
foreach(MyUserControl muc in
myListBox)
{
//do what you want
}
Easy huh? :)