I want to bind a model to a view.
The problem is that it doesn't bind.
this.BindingContext = Model;
stackLayoutF.Children.Add(new Entry() { Text = Model.EditFirstname, WidthRequest = 100 });
stackLayoutContent.Children.Add(stackLayoutF);
private string _editFirstname = "United";
public string EditFirstname
{
get { return _editFirstname; }
set
{
SetProperty(ref _editFirstname, value);
}
}
It loads normally with the text "United". When I change the text, nothing happened.
I probably forgotten something.
Please let me know if you can help me with this problemn.
You didn't specify any bindings anywhere. You will need to write something like:
var entry = new Entry() { WidthRequest = 100 };
entry.SetBinding(Entry.TextProperty, nameof(ViewModel.EditFirstName));
stackLayoutF.Children.Add(entry);
Refer to the official docs here, there are multiple examples of this: https://learn.microsoft.com/en-us/xamarin/xamarin-forms/app-fundamentals/data-binding/basic-bindings
Related
I've only really just started on Tornadofx and was having a bit of trouble trying to figure out how to reload a view so the controls in that view are refreshed.
Below is a simplified version of the code I'm working with. I've got a loop to generate radio-button controls based on strings in a list.
class MainView: View("MainView") {
override val root = vbox {
for(x in radioText) {
radiobutton(x, radioGroup) {
action {
radioSelected = this#radiobutton.text
}
}
}
button("Next") {
action {
// Reload View to update radiobuttons with new values
}
}
}
}
In the program I need to go through several sets of these radio buttons, and so the idea was that each time the user presses the "Next" button, the items in the radioText list would be updated to match the next set of radio-buttons. Then I was looking for a way to get the view to update with these new values.
I tried using openWindow() to open a new instance of the view, but then when I used close() to get rid of the previous instance and ended up closing both windows.
button("Next") {
action {
MainView().openWindow()
close()
}
}
Any help with this would be much appreciated,
Thanks.
If I understood correctly, you are trying to have a list of string and generate radiobuttons with it. So, by adding the variables to your example, would be something like this:
class MainView: View("MainView") {
val radioText = ArrayList<String>()
var radioGroup : ToggleGroup by singleAssign()
lateinit var radioSelected : String
override val root = vbox {
radioText.addAll(arrayListOf("One","Two","Three","Four"))
radioGroup = togglegroup(){}
for(x in radioText) {
radiobutton(x,radioGroup) {
action {
radioSelected = text //You don't need this#radiobutton.text
}
}
}
button("Next") {
action {
// Reload View to update radiobuttons with new values
}
}
}
}
I thing is a better idea having your radiobutton created by a listview, wich would be updated by a observable list of string, like I do bellow:
class MainView2: View("MainView") {
// this is a list of observable string, so when the items on his list change
// the listview is updated
val radioText = FXCollections.observableArrayList<String>()
var radioGroup : ToggleGroup by singleAssign()
lateinit var radioSelected : String
override val root = vbox() {
prefWidth = 200.0
prefHeight = 300.0
radioText.setAll("One","Two","Three","Four")
radioGroup = togglegroup(){}
listview<String>(radioText){
// Setting listview height dinamically
fixedCellSize = 25.0
prefHeightProperty().bind(radioText.sizeProperty.multiply(fixedCellSizeProperty().add(2)))
// Generating the radiobutton acording to strings on radioText
cellFormat {
graphic = cache(it){
radiobutton(it,radioGroup){
action {
radioSelected = text
}
}
}
}
}
button("Next") {
action {
radioText.clear()
radioText.setAll("Five","Six","Seven","Eight","Nine","Ten")
}
}
}
}
Please let me know if there is something you don't understand on my aproach.
Am trying to load ItemSource of a picker when the picker is focused.
But the data is not loaded on 1st focus.
here is the code sample
List<object> itmSrc;
Picker picker = new Picker();
itmSrc = Controls[i].ItemSource;
picker.Focused += BindItemSourceOnFocus;
public void BindItemSourceOnFocus(object sender, FocusEventArgs e)
{
var p = e.VisualElement as Picker;
p.ItemsSource = itmSrc;
}
If any other different approach is possible, let me know.
You can do it adding items on an async method, or another thread. Load the data on view focus is just transferring the issue to another place, and it gives a bad user experience at all.
If you run a code block inside a Task.Run(), for example, this code will be executed on another thread, and the interface should not hang on data loading.
Something like this:
public class MyPage : ContentPage
{
List<object> itmSrc;
Picker picker;
public MyPage()
{
// Your stuff goes here
itmSrc = new List<object>();
picker = new Picker();
StackLayout content = new StackLayout();
content.Crindren.Add(picker);
this.Content = content;
Task.Run(() => LoadData());
}
private void LoadData()
{
// Get your data from anywhere and put it on the itemSrc from here.
// Then...
picker.ItemsSource = itmSrc;
}
}
I hope it helps.
I'm developing my first Visual Studio (2015 Community) Command Menu and I'm trying to get access to IEditorOperations to delete text, send backspace etc. but I'm not sure how to. I can do:
var Service = Provider.GetService(typeof(IEditorOperationsFactoryService)) as IEditorOperationsFactoryService;
Service.GetEditorOperations(???);
I'm not sure what to pass in the ??? since I don't have access to an ITextView instead what I have is a IVsTExtView via:
IVsTextView View;
IVsTextManager Manager = (IVsTextManager)ServiceProvider.GetService(typeof(SVsTextManager));
int MustHaveFocus = 1;
Manager.GetActiveView(MustHaveFocus, null, out View);
When creating the Command Menu, VS generates a template for me with a private ctor creating the command service, binding it to the command set id etc. An overridden Initialize method, and a bunch of properties.
Any ideas?
EDIT: After help from Sergey, I managed to get a bit further. But now I get a null when I try to get the IEditorOperationsFactoryService, all the other values are valid.
static IEditorOperations GetEditorService(IServiceProvider Provider, IVsTextView VsView)
{
IEditorOperations Result;
try
{
var Model = (IComponentModel)Provider.GetService(typeof(SComponentModel));
var Editor = (IEditorOperationsFactoryService)Provider.GetService(typeof(IEditorOperationsFactoryService)); // returns null
var Adaptor = Model.GetService<IVsEditorAdaptersFactoryService>();
IWpfTextView TextView = Adaptor.GetWpfTextView(VsView);
Result = Editor.GetEditorOperations(TextView);
}
catch (Exception e)
{
System.Windows.Forms.MessageBox.Show(e.ToString());
Result = null;
}
return (Result);
}
You can get IEditorOperationsFactoryService instance from variable named Model, like this:
var Model = (IComponentModel)this.ServiceProvider.GetService(typeof(SComponentModel));
var Editor = (IEditorOperationsFactoryService)Model.GetService<IEditorOperationsFactoryService>();
You can get IWpfTextView (that implements ITextView) from IVsTextView using:
IVsTextView textView = ...;
IWpfTextView v = GetEditorAdaptersFactoryService().GetWpfTextView(textView);
private Microsoft.VisualStudio.Editor.IVsEditorAdaptersFactoryService GetEditorAdaptersFactoryService()
{
Microsoft.VisualStudio.ComponentModelHost.IComponentModel componentModel =
(Microsoft.VisualStudio.ComponentModelHost.IComponentModel)serviceProvider.GetService(
typeof(Microsoft.VisualStudio.ComponentModelHost.SComponentModel));
return componentModel.GetService<Microsoft.VisualStudio.Editor.IVsEditorAdaptersFactoryService>();
}
I have a problem and It's 10 days that I am working and can't solve it.I made a layout for each row for ListView.This Layout Contains a linearLayout that there is a TextView and a WebView inside it.Now I Need a C# Project that I can add a new Row to the ListView with new text and url whenever I want.For Example: button.click { ListView.add(Resource.Layout.Items, "Text","Url")}..I know this command is wrong. Just I wanted to clear the problem for you.
I khnow it's custom Row layout and I read manny examples at this site other sites and Xamarin site about that,adapters,... but I can't do it. :(
Please answer me correctly.
It is very important for me.
Thanks a lot.
You need to create an adapter that can work with you custom objects as items. It could look like the following sample:
public class MyAdapter : BaseAdapter<MyItem>
{
readonly LayoutInflater inflater;
List<MyItem> myItemList;
public MyAdapter(Context context)
{
inflater = LayoutInflater.FromContext(context);
myItemList = YOUR_DATASOURCE.GetMyItems();
}
public override MyItem this [int index]
{
get { return myItemList[index]; }
}
public override int Count
{
get { return myItemList.Count; }
}
public override long GetItemId(int position)
{
return position;
}
public override View GetView(int position, View convertView, ViewGroup parent)
{
View view = convertView ?? inflater.Inflate(Resource.Layout.MyItemLayout, parent, false);
var item = myItemList[position];
var viewHolder = view.Tag as MyViewHolder;
if (viewHolder == null)
{
viewHolder = new MyViewHolder();
viewHolder.Web = view.FindViewById<WebView>(Resource.Id.MyItemLayout_Icon);
viewHolder.Name = view.FindViewById<TextView>(Resource.Id.MyItemLayout_Title);
view.Tag = viewHolder;
}
viewHolder.Web.Url = item.Url; //You need to check how you have to set the url for a WebView
viewHolder.Name.Text = item.Text;
return view;
}
public override void NotifyDataSetChanged()
{
myItemList = YOUR_DATASOURCE.GetMyItems();
base.NotifyDataSetChanged();
}
}
class MyViewHolder : Java.Lang.Object
{
public WebView Web { get; set; }
public TextView Name { get; set; }
}
You apply the adapter to your ListView with ListView.Adapter = new MyAdapter(Activity);. Each time you change an item in you button click event, you tricker (ListView.Adapter as MyAdapter).NotifyDataSetChanged(); which will force the adapter to reload and refresh the data.
YOUR_DATASOURCE represents the point in your code where you store the informations like the url or text of all your items. This could typically be a database or something similar. While GetMyItems() is a method for example to query your database.
Hope this clears things up.
hopefully you can help me. First of all, let me explain what my problem is.
I have two ViewModels. The first one has e.g. stored information in several textboxes.
For example
private static string _tbxCfgLogfile;
public string TbxCfgLogfile
{
get { return _tbxCfgLogfile; }
set
{
_tbxCfgLogfile = value;
NotifyOfPropertyChange(() => TbxCfgLogfile);
}
}
The other ViewModel has a Button where i want to save this data from the textboxes.
It does look like this
public bool CanBtnCfgSave
{
get
{
return (new PageConfigGeneralViewModel().TbxCfgLogfile.Length > 0 [...]);
}
}
public void BtnCfgSave()
{
new Functions.Config().SaveConfig();
}
How can i let "CanBtnCfgSave" know that the condition is met or not?
My first try was
private static string _tbxCfgLogfile;
public string TbxCfgLogfile
{
get { return _tbxCfgLogfile; }
set
{
_tbxCfgLogfile = value;
NotifyOfPropertyChange(() => TbxCfgLogfile);
NotifyOfPropertyChange(() => new ViewModels.OtherViewModel.CanBtnCfgSave);
}
}
It does not work. When i do remember right, i can get the data from each ViewModel, but i cannot set nor Notify them without any effort. Is that right? Do i have to use an "Event Aggregator" to accomplish my goal or is there an alternative easier way?
Not sure what you are doing in your viewmodels - why are you instantiating viewmodels in property accessors?
What is this line doing?
return (new PageConfigGeneralViewModel().TbxCfgLogfile.Length > 0 [...]);
I can't be sure from your setup as you haven't mentioned much about the architecture, but sincce you should have an instance of each viewmodel, there must be something conducting/managing the two (or one managing the other)
If you have one managing the other and you are implementing this via concrete references, you can just pick up the fields from the other viewmodel by accessing the properties directly, and hooking the PropertyChanged event of the child to notify the parent
class ParentViewModel : PropertyChangedBase
{
ChildViewModel childVM;
public ParentViewModel()
{
// Create child VM and hook up event...
childVM = new ChildViewModel();
childVM.PropertyChanged = ChildViewModel_PropertyChanged;
}
void ChildViewModel_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
{
// When any properties on the child VM change, update CanSave
NotifyOfPropertyChange(() => CanSave);
}
// Look at properties on the child VM
public bool CanSave { get { return childVM.SomeProperty != string.Empty; } }
public void Save() { // do stuff }
}
class ChildViewModel : PropertyChangedBase
{
private static string _someProperty;
public string SomeProperty
{
get { return _someProperty; }
set
{
_someProperty = value;
NotifyOfPropertyChange(() => SomeProperty);
}
}
}
Of course this is a very direct way to do it - you could just create a binding to CanSave on the child VM if that works, saving the need to create the CanSave property on the parent