I added custom listview. And I added checbox in rows. I have to use ItemChecked event but I have an error->"cannot resolve symbol 'ItemChecked'"
and "cannot resolve symbol 'ItemCheckedEventArgs '"
ziyaret_listesi = FindViewById<ListView>(Resource.Id.list_ziyaret_kayitlari);
ziyaret_listesi.Adapter = new CustomAdapterZiyaretRapor(this, list_ziyaret_rapor);
ziyaret_listesi.ItemChecked += ListView_ItemChecked;
private void ziyaret_listesi_ItemChecked(object sender, ItemCheckedEventArgs e)
{
// the checked state of an item has changed
}
Why cannot resolve itemchecked event in c# Xamarin?
Related
So, I have a listview and I want it whenever an item is created to scroll to that item (bottom). Because I am using MVVM I found really nice explanation on how to make a new control that inherits from listview that scrolls down. The problem is that this answer (the third) is referring to WPF 6 years ago.
I am making a UWP app, so I copied the code and tried to format it to my needs. The following code doesn't give any error or exception but instead it loads the "ChatListView" as I call it perfectly and then does nothing. The comments are only a bit edited compared to the original code.
What can I do ? Thank you in advance!
public class ChatListView : ListView
{
//Define the AutoScroll property. If enabled, causes the ListBox to scroll to
//the last item whenever a new item is added.
public static readonly DependencyProperty AutoScrollProperty =
DependencyProperty.Register(
"AutoScroll",
typeof(Boolean),
typeof(ChatListView),
new PropertyMetadata(
true, //Default value.
new PropertyChangedCallback(AutoScroll_PropertyChanged)));
//Gets or sets whether or not the list should scroll to the last item
//when a new item is added.
public bool AutoScroll
{
get { return (bool)GetValue(AutoScrollProperty); }
set { SetValue(AutoScrollProperty, value); }
}
//Event handler for when the AutoScroll property is changed.
//This delegates the call to SubscribeToAutoScroll_ItemsCollectionChanged().
//d = The DependencyObject whose property was changed.</param>
//e = Change event args.</param>
private static void AutoScroll_PropertyChanged(
DependencyObject d, DependencyPropertyChangedEventArgs e)
{
SubscribeToAutoScroll_ItemsCollectionChanged(
(ChatListView)d,
(bool)e.NewValue);
}
//Subscribes to the list items' collection changed event if AutoScroll is enabled.
//Otherwise, it unsubscribes from that event.
//For this to work, the underlying list must implement INotifyCollectionChanged.
//
//(This function was only creative for brevity)
//listBox = The list box containing the items collection.
//subscribe = Subscribe to the collection changed event?
private static void SubscribeToAutoScroll_ItemsCollectionChanged(
ChatListView listView, bool subscribe)
{
INotifyCollectionChanged notifyCollection =
listView as INotifyCollectionChanged;
if (notifyCollection != null)
{
if (subscribe)
{
//AutoScroll is turned on, subscribe to collection changed events.
notifyCollection.CollectionChanged +=
listView.AutoScroll_ItemsCollectionChanged;
}
else
{
//AutoScroll is turned off, unsubscribe from collection changed events.
notifyCollection.CollectionChanged -=
listView.AutoScroll_ItemsCollectionChanged;
}
}
}
//Event handler called only when the ItemCollection changes
//and if AutoScroll is enabled.
//sender = The ItemCollection.
//e = Change event args.
private void AutoScroll_ItemsCollectionChanged(
object sender, NotifyCollectionChangedEventArgs e)
{
if (e.Action == NotifyCollectionChangedAction.Add)
{
int count = Items.Count;
ScrollIntoView(Items[count - 1]);
}
}
//Constructor a new ChatListView.
public ChatListView()
{
//Subscribe to the AutoScroll property's items collection
//changed handler by default if AutoScroll is enabled by default.
SubscribeToAutoScroll_ItemsCollectionChanged(
this, (bool)AutoScrollProperty.GetMetadata(typeof(ChatListView)).DefaultValue);
}
}
If you want to create a chat application you can use the ItemsStackPanel's ItemsUpdatingScrollMode particular property to KeepLastItemInView value to scroll to the latest item.
Usage:
<ListView>
<ListView.ItemsPanel>
<ItemsPanelTemplate>
<ItemsStackPanel ItemsUpdatingScrollMode="KeepLastItemInView" />
</ItemsPanelTemplate>
</ListView.ItemsPanel>
</ListView>
Note: KeepLastItemInView enum member was introduced in the 14393 SDK.
Related link:
https://learn.microsoft.com/en-us/uwp/api/Windows.UI.Xaml.Controls.ItemsStackPanel#properties_
The accepted answer is pretty nice. However I there is one thing it won't do (at least if I simply copy and paste the above XAML): it won't do its intended scrolling if, say, the user was away from that page while new items were added, and then they navigated to the page.
For that I had to hook into
protected override void OnNavigatedTo(NavigationEventArgs e)
{
base.OnNavigatedTo(e);
if (MyListView.Items.Count == 0)
return;
object lastItem = MyListView.Items[MyListView.Items.Count - 1];
MyListView.ScrollIntoView(lastItem);
}
In my Eclipse RCP application I display some business data in a TableViewer.
I want the user to be able to drag a row from the table viewer and drop it on the windows desktop/explorer. Windows should then create a file with the data from the selected row that I could provide in the dragSetData(..) method of the DragSourceAdapter class.
How to implement this? It seems that using FileTransfer as the dragSourceSupport on the table viewer is the way to go as it trigger a call to the dragSetData() method. But what object should I create and assign to "event.data" in this method?
A working example would be appreciated.
I've implemented the reverse without problem, i.e. drag a file from windows explorer onto the TableViewer and add a row in the table. There are plenty on sample for this on the net but can't find a sample of the opposite, drag from eclipse to the OS
[edit + new requirement]
So I understand that I have to create a temporary file somewhere and set the name of that temp file in event.data in dragSetData()
Q: is there a simpler way to do that, eg set somewhere (iun data) the content of the file directly without the temp file?
There is another requirement. When the drop operation is about to occur, I want to show a popup to the user that will have to choose what "business data" from the "row" he wants to export and the name of the file that will be created. I tried the following (only asking for the filename for now) but it does not work as expected as the popup shows up as soon as the cursor reach the first pixel outside my app. I would like to show the popup just "before" the drop operation occurs.
Q: is there a way to have this popup show just before the drop operation occurs, ie when the user "release" the mouse button?
#Override
public void dragSetData(final DragSourceEvent event){
if (FileTransfer.getInstance().isSupportedType(event.dataType)) {
// Will be a more complex dialog with multiple fields..
InputDialog inputDialog = new InputDialog(shell, "Please enter a file name", "File Name:", "", null);
if (inputDialog.open() != Window.OK) {
event.doit = false;
return;
}
event.data = new String[] { inputDialog.getValue() };
}
}
The event.data for FileTransfer is an array of file path strings.
You DragSourceAdapter class might look something like:
public class MyDragSourceAdapter extends DragSourceAdapter
{
private final StructuredViewer viewer;
public MyDragSourceAdapter(final StructuredViewer viewer)
{
super();
this.viewer = viewer;
}
#Override
public void dragStart(final DragSourceEvent event)
{
IStructuredSelection selection = viewer.getStructuredSelection();
if (selection == null)
return;
// TODO check if the selection contains any files
// TODO set event.doit = false if not
}
#Override
public void dragSetData(final DragSourceEvent event)
{
if (!FileTransfer.getInstance().isSupportedType(event.dataType))
return;
IStructuredSelection selection = viewer.getStructuredSelection();
List<String> files = new ArrayList<>(selection.size());
// TODO add files in the selection to 'files'
event.data = files.toArray(new String [files.size()]);
}
}
and you install it on your viewer with:
MyDragSourceAdapter adapter = new MyDragSourceAdapter(viewer);
viewer.addDragSupport(DND.DROP_COPY, new Transfer [] {FileTransfer.getInstance()}, adapter);
I am creating button control in my Windows 8 metro application made in C++/CX. I'd like to make an event which is triggered when the button is pressed. But I have no clue how to add an event to a button in C++/CX.
If you want to do this in C# it is as following:
Button btnDoSomething = new Button();
btnDoSomething.MouseClick += new MouseEventHandler(iGotClickedByTheButton);
void iGotClickedByTheButton(object sender, MouseEventArgs e)
{
MessageBox.Show("Hello I got clicked!");
}
So my approach was doing something like this:
Button^ btnDoSomething = ref new Button();
btnDoSomething->Tapped += ref new TappedEventHandler(sender, iGotClickedByTheButton);
void iGotClickedByTheButton(Platform::Object^ sender, Windows::UI::Xaml::RoutedEventArgs^ e)
{
MessageDialog^ msgDlg = ref new MessageDialog("Hello I got clicked!");
msgDlg->ShowAsync();
}
This however resulted in an error at this place:
btnDoSomething->Tapped += ref new TappedEventHandler(sender, iGotClickedByTheButton);
It displayed the following error:
Error: invalid delegate initializer -- function does not match the
delegate type.
Solved it by doing the following:
Button^ btnDoSomething = ref new Button();
btnDoSomething->Click += ref new Windows::UI::Xaml::RoutedEventHandler(this, &MyProjectName::MainPage::iGotClickedByTheButton);
I have a problem with validation on form actually sub-form.
In my website I have some kind of table and "Add row" button (BlockingAjaxSubmitLink).
When I try add let say 2 rows, I get validation error (because row in this table has Required=True parameter) and I can't add another row. I tried use simple AjaxLink but it doesn't have reference to form in onClick method and when I complete some rows and click "Add row" this data get lost.
I want to enable validation only after "save" button click.
Any idea how to deal with this problem?
I do something like you want using an AjaxLink.
My AjaxLink:
private AjaxLink addNewRow = new AjaxLink("addNewRow") {
#Override
public void onClick(AjaxRequestTarget target) {
MyEntityObject newTableRowObject = new MyEntityObject(irrelevantParameter);
entityObjectTableService.createNewRowInDB(newTableRowObject );
target.add(listViewContainer);
}
};
In this code the listViewContainer is a WebMarkupContainer which contains a ListView holding the table rows.
When i click this AjaxLink a new object representing a row in my table is added to the database and then the container containing the ListView is being refreshed refreshing the ListView and the new empty object is being fetched from the DB and shown as a new row in my table at the end.
Depending on your structure maybe you are looking after disabling validation using setDefaultFormProcessing(true); - http://ci.apache.org/projects/wicket/apidocs/6.x/org/apache/wicket/markup/html/form/AbstractSubmitLink.html#setDefaultFormProcessing%28boolean%29
For now I write some kind of hack
First I set
addKnowledgeLink.setDefaultFormProcessing(false);
and next
BlockingAjaxSubmitLink<Object> addKnowledgeLink = new BlockingAjaxSubmitLink<Object>(
"link_knowledge_add") {
#Override
protected void onSubmit(AjaxRequestTarget target, Form<?> form) {
ChangeDataForm.this.process(this);
/* some code */
target.add(form.get(MY_CONTAINER_ID));
}
(...)
and my hack...
//HACK
public void process(IFormSubmitter object){
if (!isEnabledInHierarchy() || !isVisibleInHierarchy())
{
return;
}
// run validation
validate();
/*if (hasError())
{
// mark all children as invalid
markFormComponentsInvalid();
// let subclass handle error
callOnError(object);
}
else
{*/
// mark all children as valid
markFormComponentsValid();
// before updating, call the interception method for clients
beforeUpdateFormComponentModels();
// Update model using form data
updateFormComponentModels();
// validate model objects after input values have been bound
onValidateModelObjects();
if (hasError())
{
callOnError(object);
return;
}
// Form has no error
delegateSubmit(object);
//}
}
and I ovveride one method
#Override
protected void onError(){
super.onError();
this.updateFormComponentModels();
}
I know it is ugly solution but I couldn't figure out anything better..
And I couldn't shutdown feedback messages
I have a bunch of TextBox-es generated dynamically. At the step of creation I'm assigning the ID property for them.
e.g.
id = ...
Button b = new Button();
b.setText("add textbox");
b.addClickHandler(new Clickhandler() {
Textbox tb = new TextBox();
tb.getElement().setId(Integer.toString(id));
tb.setText("some text");
}
id += 1;
I need to access them later by their IDs, but I cannot do it.
I tried to use the DOM object in order to get a widget, but it produces an exception:
String id = "some id";
Element el = DOM.getElementById(id);
String value = el.getAttribute("value"); - this line produces an exception.
I've also tried to use el.getInnerText, el.getNodeValue - no luck. I have see in the chrome debugger - the textboxes don't have the 'value' property.
you can get the widget associated to an element this way:
public static IsWidget getWidget(com.google.gwt.dom.client.Element element) {
EventListener listener = DOM
.getEventListener((com.google.gwt.dom.client.Element) element);
// No listener attached to the element, so no widget exist for this
// element
if (listener == null) {
return null;
}
if (listener instanceof Widget) {
// GWT uses the widget as event listener
return (Widget) listener;
}
return null;
}
Since you are constructing your textboxes in gwt java code, why not put them into a map and access them later?
One thing to keep in mind is the difference between an attribute and a property in HTML/DOM. In your example, "value" is a property. You could try Element#getPropertyString. It used to be that attributes and properties were used interchangeably, but in modern browsers that's no longer the case.