I have a problem regarding the comportment my ComboBox.
First I use a combobox to display all elements in a IEnumarale.
Then, with a button wich open a popup, the user can add an alement to that list.
The problem is that when the user validate his choice and close the popup, the element is not automatly added to the ComboBox without doing a refresh of the page.
The combobox is coded as follows :
<telerik:RadComboBox x:Name="MyElements"
SelectionChanged="MyElements_OnSelectionChanged"
ItemTemplate="{StaticResource ComboBoxElementsTemplate}"
ItemsSource="{Binding ListElements}"/>
The constructor of the list is :
public IEnumerable<Element> ListElements
{
get { return _listElements; }
set
{
_listElements= value;
RaisePropertyChange("ListElements");
}
}
And the code behind of the button to validate the user choice in the popup :
private ObservableCollection<HistoriqueElement> elementList = null;
private void SelectClick(object sender, RoutedEventArgs e)
{
var element= _GridList.SelectedItem as HistoriquePasserelle;
if (_GridList.SelectedItem != null)
{
var installation = this.DataContext as Installation;
if (installation != null && element!= null)
{
element.DateFin = DateTime.Now;
HistoriqueElement newElement= new HistoriqueElement()
{
Installation = installation,
ContactAction = GlobalActeurs.Current.CurrentContact,
Date = DateTime.Now,
Element = element.Element,
StatutElement = element.StatutElement ,
Owner= element.Owner,
};
elementList.Remove(element);
}
MainPage.ClosePopup();
}
}
When the user choose a new element in the list display in the popup and validate his choice, he returns to the main page, but his choice is not automatically added to the combobox.
I can post you any parts of the code.
Thank you in advance.
The method OnDataContextChanged :
public override void OnDataContextChanged(DependencyPropertyChangedEventArgs e)
{
if (e.NewValue is Installation)
{
if (MainPage.CurrentInstallation.LastElements != null)
{
ListElements = MainPage.CurrentInstallation.LastElements;
MyElements.SelectedIndex = 0;
}
else
{
LoadOperation<Element> operation =
_context.Load(_context.GetCurrentElementsByInstallationId(MainPage.CurrentInstallation.Id));
this._busy.IsBusy = true;
operation.Completed += delegate
{
this._busy.IsBusy = false;
if (operation.ManageError())
{
ListElements = operation.Entities;
}
};
}
this.DataContext = this;
}
else
{
RaisePageTitleChanged();
if (MainPage.CurrentInstallation == null)
return;
}
if (MyElements.SelectedItem == null && MyElements.Items.Any())
{
MyElements.SelectedIndex = 0;
}
}
If the collection the ItemsSource is bound to implement INotifyCollection changed, that is, it's an ObservableCollection<>, then the combobox will be notified of any changes to the collection and you will not need to rebind or refresh, it will all be automatic.
Once you add the item to the list, bind the itemsource to the combobox, then you dont have to refersh.
MyElements.ItemsSource = ListElements
Related
I want to search in a data grid via typing in a textbox, but I am unable to find solution.
Do I need to do any binding? If so, then how do I do it?
If you want filter text in your Datagrid i.e by Name, try this...
private bool DataMatchesFilterText(User user, string filterText)
{
return user.Name.ToString() == filterText;
}
Yeah you will require your data grid to be bound to a Property that contains all your data.
Then add a event handler to your Textbox to act on one of the key events, e.g.
Xaml:
<TextBox x:Name="SearchBox" KeyUp="FilterTextBox_TextChanged" />
Then in the code behind you need to act on that event. Here you need to extract the filter text, get the rows in your DataGrid and then perform some method to determine if it should be visible or not. You will need to implement your own DataMatchesFilterText method.
Codebehind:
private void FilterTextBox_TextChanged(object sender, KeyEventArgs e)
{
var filterTextBox = (TextBox)sender;
var filterText = filterTextBox.Text;
SetRowVisibilityByFilterText(filterText);
}
private void SetRowVisibilityByFilterText(string filterText)
{
GetVisibleRows(yourGrid)
.ToList()
.ForEach(
x =>
{
if (x == null) return;
x.Visibility =
DataMatchesFilterText(x.Item as YourRowProperty, filterText) ? Visibility.Visible : Visibility.Collapsed;
});
}
public static IEnumerable<DataGridRow> GetVisibleRows(DataGrid grid)
{
if (grid == null || grid.Items == null) yield break;
int count = grid.ItemsSource == null
? grid.Items.Count
: grid.ItemsSource.Cast<object>().Count();
for (int i = 0; i < count; i++)
{
yield return (DataGridRow)grid.ItemContainerGenerator.ContainerFromIndex(i);
}
}
I am trying to convert my Winforms application to WPF format, I am trying to convert the double click of my listview at the moment. I have done this so far:
private void listView1_DoubleClick(object sender, MouseButtonEventArgs e)
{
ListViewItem item = this.listView1.SelectedItems[0];
if (item.Tag != null)
{
ControllerInfo controllerInfo = (ControllerInfo)item.Tag;
if (controllerInfo.Availability == Availability.Available)
{
if (controllerInfo.IsVirtual)
{
this.controller = ControllerFactory.CreateFrom(controllerInfo);
this.controller.Logon(UserInfo.DefaultUser);
listView1.Items.Clear();
listView1.Items.Add(item);
EnableControllerFunctionality();
}
else //real controller
{
if (MessageBox.Show("This is NOT a virtual controller, do you really want to connect to that?","Warning", MessageBoxButton.YesNo, MessageBoxImage.Warning) == MessageBoxResult.Yes)
{
this.controller = ControllerFactory.CreateFrom(controllerInfo);
this.controller.Logon(UserInfo.DefaultUser);
listView1.Items.Clear();
listView1.Items.Add(item);
EnableControllerFunctionality();
}
}
}
else
{
MessageBox.Show("Selected controller not available.");
}
}
The problem is with the first line :
ListViewItem item = this.listView1.SelectedItems[0];
stating 'cannot implicitly convert from object to listviewitem. An explicit conversion exists
I have been trying to find this conversion but to no avail. I feel as though I am missing something key.
I have looked here and here and many other places, but I just can't seem to get the ItemContainerGenerator.ContainerFromItem method to work on a WPF TreeView! I have tried to pass in the actual item I want to see, but not getting anywhere with that, I just tried to get the first item in my TreeView. Here's my sample code:
private static bool ExpandAndSelectItem(ItemsControl parentContainer, object itemToSelect)
{
// This doesn't work.
parentContainer.BringIntoView();
// May be virtualized, bring into view and try again.
parentContainer.UpdateLayout();
parentContainer.ApplyTemplate();
TreeViewItem topItem = (TreeViewItem)parentContainer.ItemContainerGenerator.ContainerFromItem(parentContainer.Items[0]);
// Can't find child container unless the parent node is Expanded once
if ((topItem != null) && !topItem.IsExpanded)
{
topItem.IsExpanded = true;
parentContainer.UpdateLayout();
}
}
As you can see, I have tried to call many "updating" methods to try to get the TreeView to be "visible" and "accessible". The Catch-22 seems to be that you can't use ContainerFromItem() unless the first TreeViewItem is expanded, but I can't grab the TreeViewItem to Expand it until ContainerFromItem() works!
Another funny thing that is happening is this: When I open this window (it is a UserControl), ContainerFromItem() returns nulls, but if I close the window and open it back up, ContainerFromItem() starts returning non-nulls. Is there any event I should be looking for or forcing to fire?
Turns out the event I was looking for was "Loaded". I just attached an event handler onto my treeview in the XAML, and called my logic in that event handler.
<TreeView x:Name="MyTreeView"
Margin="0,5,0,5"
HorizontalAlignment="Left"
BorderThickness="0"
FontSize="18"
FontFamily="Segoe WP"
MaxWidth="900"
Focusable="True"
Loaded="MyTreeView_Load">
...
</TreeView>
The event handler:
private void MyTreeView_Load(object sender, RoutedEventArgs e)
{
ShowSelectedThing(MyTreeView, ThingToFind);
}
// Gotta call the TreeView an ItemsControl to cast it between TreeView and TreeViewItem
// as you recurse
private static bool ShowSelectedThing(ItemsControl parentContainer, object ThingToFind)
{
// check current level of tree
foreach (object item in parentContainer.Items)
{
TreeViewItem currentContainer = (TreeViewItem)parentContainer.ItemContainerGenerator.ContainerFromItem(item);
if ((currentContainer != null) && (item == ThingToFind)
{
currentContainer.IsSelected = true;
currentContainer.BringIntoView();
return true;
}
}
// item is not found at current level, check the kids
foreach (object item in parentContainer.Items)
{
TreeViewItem currentContainer = (TreeViewItem)parentContainer.ItemContainerGenerator.ContainerFromItem(item);
if ((currentContainer != null) && (currentContainer.Items.Count > 0))
{
// Have to expand the currentContainer or you can't look at the children
currentContainer.IsExpanded = true;
currentContainer.UpdateLayout();
if (!ShowSelectedThing(currentContainer, ThingToFind))
{
// Haven't found the thing, so collapse it back
currentContainer.IsExpanded = false;
}
else
{
// We found the thing
return true;
}
}
}
// default
return false;
}
Hope this helps someone. Sometimes in the real world, with demanding customers, weird requirements and short deadlines, ya gotta hack!
When the container generator's status is 'NotStarted' or 'ContainersGenerating', you can't find the container.
Use this method to find the container of data item.
private static async Task<TreeViewItem> FindItemContainer(ItemsControl itemsControl, object item)
{
var generator = itemsControl.ItemContainerGenerator;
if (generator.Status != GeneratorStatus.ContainersGenerated)
{
var tcs = new TaskCompletionSource<object>();
EventHandler handler = null;
handler = (s, e) =>
{
if (generator.Status == GeneratorStatus.ContainersGenerated)
{
generator.StatusChanged -= handler;
tcs.SetResult(null);
}
else if (generator.Status == GeneratorStatus.Error)
{
generator.StatusChanged -= handler;
tcs.SetException(new InvalidOperationException());
}
};
generator.StatusChanged += handler;
if (itemsControl is TreeViewItem tvi)
tvi.IsExpanded = true;
itemsControl.UpdateLayout();
await tcs.Task;
}
var container = (TreeViewItem)generator.ContainerFromItem(item);
if(container == null)
{
foreach (var parentItem in itemsControl.Items)
{
var parentContainer = (TreeViewItem)generator.ContainerFromItem(parentItem);
container = await FindItemContainer(parentContainer, item);
if (container != null)
return container;
}
}
return container;
}
private void Lv_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
ListView Lv = (ListView)sender;
Lv.UpdateLayout(); // 1.step
DependencyObject Dep = Lv.ItemContainerGenerator
.ContainerFromItem(Lv.SelectedItem);
((ListViewItem)Dep).Focus(); //2.step
}
I had come across this issue time ago and now again I got stuck with it for quite a while. Any MessageBox launch or an expand or dropdown on your particular control type, any of these do the job and start the ItemContainerGenerator. The .UpdateLayout() however is the right thing to do, before the .Focus(). Should be analogous for a Treeview, or one of its Items.
I have one textBox and one combobox in wpf usercontrol. ComboxBox is binded to ICollectionView (CurencyList) which populates Currency Pairs like GBP/EUR,CLP/EUR,USD/EUR,EUR/USD etc. Whenever the user writes in textbox e.g. EUR the combobox should get filtered and display the dropdownlist with EUR as the second currency.
For this I have used like:
public string Currency
{
get {
return _criteriaType.currency; }
set
{
if (_criteriaType.currency != value)
{
_criteriaType.currency = value.EmptyOrWhiteSpaceAsNull();
base.OnPropertyChanged("Currency");
CurrencyList.Filter = new Predicate<object>(Contains);
}
}
}
public bool Contains(object de)
{
CurrencyPair o = de as CurrencyPair;
if (Currency != null || Currency == string.Empty)
{
return (o.name.Substring(3, 4).ToLower().Contains(Currency.ToLower()));
}
else
{
IsOpen = false;
OnPropertyChanged("IsOpen");
return false;
}
}
CurrencyList is coming from a webservice:
private ICollectionView GetCurrencyPair()
{
strCurrencyPair.arg0 = (Currency != string.Empty && Currency != null) ? Convert.ToString(Currency).ToUpper() : string.Empty;
string[][] cPair = ServiceLocator.Resolve<IWebServiceRepository>().BusinessWebService.getCurrenyPairs(strCurrencyPair);
foreach (string[] item in cPair)
{
IList.Add(new CurrencyPair() { name = (Convert.ToString(item[0]).ToUpper() + "/" + Convert.ToString(item[1]).ToUpper()) });
}
return CurrencyList =CollectionViewSource.GetDefaultView(IList);
}
Filtering is working fine. But when the user deletes the currency from textbox with backward arrow key from keyboard, the combobox filtered to nothing i.e. dropdownlist is empty.
How to overcome this problem. kindly suggest?
you need to update your collection view through the text change event
private void OnTextChanged(object sender, Eventargs e) {
var vm = yourViewModelOrWhatEver;
((ICollectionView)vm.CurrencyList).Refresh();
}
or set the filter predicate once and fire only the refresh on currency change
public void ctor() {
CurrencyList.Filter = new Predicate<object>(Contains);
}
public string Currency {
get { return _criteriaType.currency; }
set {
if (_criteriaType.currency == value) {
return;
}
_criteriaType.currency = value.EmptyOrWhiteSpaceAsNull();
base.OnPropertyChanged("Currency");
CurrencyList.Refresh(); // refresh/filter the collection view
}
}
hope that helps
EDIT
you say
Filtering is working fine. But when the user deletes the currency from
textbox with backward arrow key from keyboard, the combobox filtered
to nothing i.e. dropdownlist is empty. How to overcome this problem.
kindly suggest?
then you must change your predicate function to this one
public bool Contains(object de)
{
CurrencyPair o = de as CurrencyPair;
if (Currency != null || Currency == string.Empty) {
// Currency == string.Empty should also true
return (Currency == string.Empty) || (o.name.Substring(3, 4).ToLower().Contains(Currency.ToLower()));
} else {
IsOpen = false;
OnPropertyChanged("IsOpen");
return false;
}
}
I would assume the issue lies with this statement: string[][] cPair =
ServiceLocator.Resolve().BusinessWebService.getCurrenyPairs(strCurrencyPair);
what is the return value from that service if you pass string.empty for strCurrencyPair as you will currently be doing once the textbox is empty from backspacing?
I have a form with several controls. There a situtions where 'textBoxOtherRelationship' is disable and the text is set to string.empty. But when I then got to another control and tab out the data appears again,while the control remains disabled.
textBoxOtherRelationship.DataBindings.Add(new Binding("Text", _binder, "RelationshipNotes"));
private void ComboBoxRelationShipSelectedValueChanged(object sender, EventArgs e)
{
if ((Constants.Relationship)comboBoxRelationShip.SelectedItem.DataValue == Constants.Relationship.Other)
{
textBoxOtherRelationship.Enabled = true;
if (_formMode != ActionMode.ReadOnly)
{
textBoxFirstName.BackColor = Color.White;
}
}
else
{
textBoxOtherRelationship.Enabled = false;
_model.RelationshipNotes = null;
textBoxOtherRelationship.Text = string.Empty;
if (_formMode != ActionMode.ReadOnly)
{
textBoxFirstName.BackColor = Color.LightYellow;
}
}
}
Hmm.. so I see this line here:
textBoxOtherRelationship.DataBindings.Add(
new Binding("Text", _binder, "RelationshipNotes"));
which tells me that you've got binding set up between the Text property on the textBoxOtherRelationship and a property called "RelationshipNotes" on the datasource _binder.
Great.
So, I'm assuming that the two-way binding works just fine and that when you type something into the textBoxOtherRelationship and that control loses focus the underlying RelationshipNotes property is getting updated as well, right?
Now, looking at your code there, I don't think the underlying datasource is being updated when you set the Text property to string.Empty because that usually doesn't happen until the textbox loses focus and you've disabled the control.
If you add:
textBoxOtherRelationship.DataBindings[0].WriteValue();
after you set the value to string.Empty that string.Empty value will get stored back to the datasource because the databinding will know there is something to update. Programmatically, it doesn't.
I see you have this line:
textBoxOtherRelationship.Enabled = false;
_model.RelationshipNotes = null; <<<----------------------
textBoxOtherRelationship.Text = string.Empty;
Is _model.RelationshipNotes what is ultimately supposed to be bound to that textbox?
The SelectedIndexChanged event doesn't commit the databindings until after the control loses focus, so the quick fix is to write the value first in your event:
private void ComboBoxRelationShipSelectedValueChanged(object sender, EventArgs e)
{
if (comboBoxRelationShip.DataBindings.Count > 0) {
comboBoxRelationShip.DataBindings[0].WriteValue();
if ((Constants.Relationship)comboBoxRelationShip.SelectedItem.DataValue ==
Constants.Relationship.Other) {
textBoxOtherRelationship.Enabled = true;
if (_formMode != ActionMode.ReadOnly) {
textBoxFirstName.BackColor = Color.White;
}
} else {
textBoxOtherRelationship.Enabled = false;
_model.RelationshipNotes = null;
textBoxOtherRelationship.Text = string.Empty;
if (_formMode != ActionMode.ReadOnly) {
textBoxFirstName.BackColor = Color.LightYellow;
}
}
}
}