I am working on xamarin.forms. I need to detect the event of tab being changed either by swapping left or right or by clicking without using custom renderer
I tried below event but it is firing in both cases when child page being pushed or tab being changed. how can i get isolated event of tab being changed
public class MyTabbedPage : TabbedPage
{
public MyTabbedPage()
{
this.CurrentPageChanged += CurrentPageHasChanged;
}
protected void CurrentPageHasChanged(object sender,EventArgs e)
{
var pages= Navigation.NavigationStack;
if (pages.Count > 0)
{
this.Title = pages[pages.Count - 1].Title;
}
else
this.Title = this.CurrentPage.Title;
}
}
This issue I am facing is: In below screenshot part1 is Homepage(title="Diary") & part2 is Childpage(title="Homework") when I change tab & again come to first tab than navigationbar title getting changed "Homework" to "Diary"(Screeshot2)
As you are on your tabbed page already you can literally just do the following
public partial class MyTabbedPage : TabbedPage
{
public MyTabbedPage()
{
InitializeComponent();
CurrentPageChanged += CurrentPageHasChanged;
}
private void CurrentPageHasChanged(object sender, EventArgs e) => Title = CurrentPage.Title;
}
if you want to use the sender you can do the following
public partial class MyTabbedPage : TabbedPage
{
public MyTabbedPage()
{
InitializeComponent();
CurrentPageChanged += CurrentPageHasChanged;
}
private void CurrentPageHasChanged(object sender, EventArgs e)
{
var tabbedPage = (TabbedPage) sender;
Title = tabbedPage.CurrentPage.Title;
}
}
Or if you can elaborate on what you are trying to do exactly I can give a better answer as I do not know what it is that you are trying to do exactly
I don't think you can achieve what you want to do, at least not like this. The event behaves the way it does and as described: it is fired whenever the current page changes, also for children.
That being said, I think you should focus on implementing the functionality you want with the tools we have. I can't really deduce from your code what you are trying to do, but it looks like you want to change the title? When a tab is changed? Why not just make some kind of condition to only do it for certain pages? For example when the page is contained in the Children collection?
Related
I am trying to code a WPF desktop Application. Currently i have a Main Window (MainWindow) and a page (Pageone) under the same solution. From my MainWindow.xaml.cs page, i have a variable (proc1) which i want to pass to my Pageone.xaml.cs page and maybe even more pages in the future to access and use for some calculation.
However i cant seem to find a method to successfully do this, i have tried making my variable "public", and instantiate the MainWindow object for my page to access it but it doesn't seem to work. (A field initializer cannot reference the non-static field, method, or property 'Pageone.pog')
MainWindow.xaml.cs
public string proc1;
public void startTroubleshootButton_Click(object sender, RoutedEventArgs e)
{
try
{
var selectedProcess = listViewProcesses.SelectedItems[0] as myProcess;
if (selectedProcess == null)
{
MessageBox.Show("no selection made");
return;
}
proc1 = selectedProcess.processName;
MessageBox.Show($"you have selected the {proc1} application ");
Pageone pg = new Pageone(this);
this.Content = pg;
}
catch(ArgumentOutOfRangeException)
{
return;
}
}
Pageone.xaml.cs
public partial class Pageone : Page
{
public Pageone(MainWindow mainWindow)
{
InitializeComponent();
}
MainWindow pog = new MainWindow();
string procName = pog.proc1;
...
I've heard that i will maybe need to use something called the MVVM or code a parameterized constructor but i'm not sure if its related to the code i'm doing. Is there a better way to go about coding this? Thanks.
It can be done like:
var window = (MainWindow)Application.Current.MainWindow;
I am trying to develop a program in which it could create forms and add controls to it at runtime.
It also should be able to save, (Open and Edit) the forms created with the new controls added it at Runtime.The Application starts In the Main form.
CODE BEHIND MAIN Form
private void Btn_CREATE_FORM_Click(object sender, EventArgs e)
{
Form_Properties fp = new Form_Properties();
fp.Show();
}
private void BTn_ADD_BTN_Click(object sender, EventArgs e)
{
/// WHAT CODE SHOULD I ENTER TO ADD BUTON TO NEW FORM
}
Basically the main form is used to create/open/save new forms and add controls to it.
When the user clicks on Create New Form button the user will be presented with the following form (FORM_PROPERTIES) in which the user can customize the name, width and height of the new form.
CODE BEHIND FORM_PROPERTIES Form
public partial class Form_Properties : Form
{
public Form_Properties()
{
InitializeComponent();
}
String form_name;
int form_width;
int form_height;
private void Btn_OK_Click(object sender, EventArgs e)
{
form_name = TBox_NAME.Text;
form_width = Convert.ToInt32(TBox_WIDTH.Text);
form_height = Convert.ToInt32(TBox_HEIGHT.Text);
New_Form nf = new New_Form();
nf.Text = form_name;
nf.Width = form_width;
nf.Height = form_height;
nf.Show();
}
}
The following image shows what happens at runtime based on the code I have written so far.
ISSUES
Need help to Write Code
To add controls to new form created.
To Save/Open/Edit Functionalities.
I also need to know the method to access properties of added controls at runtime.
eg: If the user adds a text box to the NEW FORM and decides to type some text in it, I need a method to save that text.
Is there a way for me to name the added controls?
It seems you want to build some kind of WinForms' form designer. Your program would be similar to Glade (though Glade is much more powerful).
I'm afraid the question is too broad, though. There are many questions to answer, for example, how do you describe the created interface.
While Glade uses XML, you can choose another format, such as JSON. Let's say that you have a TextBox with the word "example" inside it.
{ type:"textbox" text:"example" }
It seems you want to add your components to the form as in a stack. Maybe you could add its position. For example, a form containing a label
("data"), a textbox ("example"), and a button ("ok"), would be:
{
{ pos:0, type:"label", text:"data" },
{ pos:1, type:"textbox", text:"example" },
{ pos:2, type:"button", text:"ok" },
}
But this is just a representation. You need to a) store this when the form is saved, and b) load it back when the form is loaded.
For that, you will need a class representing the components, such as:
public class Component {
public override string ToString()
{
return string.Format( "position:{0}, text:{1}", this.Position, this.Text );
}
public int Position { get; set; }
public string Text { get; set; }
}
public class TextBoxComponent: Component {
public override string ToString()
{
return base.ToString() + "type:\"textbox\"";
}
}
...and so on. This is a big task, I'm afraid, with no simple answer.
using xamarin forms & PCL.
i want to validate the Picker using the Behavior to ensure that user picked an item from the Picker.
my behavior class is
public class PickerValidationBehaviour :Behavior<Picker>
{
private Picker _associatedObject;
public string PropertyName { get; set; }
protected override void OnAttachedTo(Picker bindable)
{
base.OnAttachedTo(bindable);
_associatedObject = bindable;
if (_associatedObject.SelectedIndex < 0 )
{
HandleValidation();
}
}
private void HandleValidation()
{
}
private void _associatedObject_SelectedIndexChanged(object sender, EventArgs e)
{
}
protected override void OnDetachingFrom(Picker bindable)
{
base.OnDetachingFrom(bindable);
_associatedObject = null;
}
}
}
and i was stuck because i want execute the validation before user action, such that the submit button will be hidden until the user fill the form.
and beside if there is any easy efficient way that i can perform the validation please mention it.
I think this scenario you should put logic in VM instead of using behavior.
Cause behavior can change some UI element, like color something and most of them are the element itself's property.
In your case, you want to change another element in Page. There is a problem, how to access another element in your page.
If you binding SelectedIndex in you VM, and when property changed you can raise another property which controls the submit button. That will be easier then do it in behavior.
I have a Main Page for my application that is formed froma number of other windows. One of which is the settings for my applications and is open/closed by clicking a button from my Main Page. This window has a View Model as well as two buttons, Save and Cancel. Pressing Cancel is used to restore the previous settings and Save just stores them. Now, when I use the main menu to close the Properties I want the Cancel to be called and am wondering about the best way to do this.
So in my view model I have something like this:
public RelayCommand CancelRC { get; private set; }
public PropertiesViewModel
{
CancelRC = new RelayCommand(RestoreProperties)
}
private RestoreProperties
{
// Restore
}
In my MainPage.xaml.cs
private void Properties_Click(object sender, RoutedEventArgs e)
{
if (PropertiesForm.Visibility == Visibility.Collapsed)
{
PropertiesForm.Visibility = Visibility.Visible;
PropertiesForm.IsSelected = true;
}
else
{
PropertiesForm.Visibility = Visibility.Collapsed;
IncidentForm.IsSelected = true;
// Send a Cancel relaycommand to the Properties View Model?
}
}
The obvious solution to me is to trigger the RelayCommand manually but I am not sure this is the most appropriate way to do it and I am not sure how you would trigger that anyway. So it this the way to do it or is there a more preferred way to do something like this?
Similarly is manually hiding and showing the Properties via the Main Page like this the best way to do it?
Remove the Properties_Click method and in your xaml do the following:
<Button Command="{Binding CancelRC}">Properties</Button>
This will cause the button to use RelayCommand.CanExecute and RelayCommand.Execute with no code on your part. The code assumes the window datacontext is set to your View Model.
Hi guys can anyone tell me how to do this... I have a Silverlight application with two XAML pages. On the first one I have a button. When the button is clicked I would like to redirect the user to the second XAML page.
How can I accomplish this?
This is what i have so far:
public partial class MainPage : UserControl
{
public MainPage()
{
InitializeComponent();
this.HelloMessage.Text = "Hello Universe";
}
private void button1_Click(object sender, RoutedEventArgs e)
{
}
private void HelloMessage_Loaded(object sender, RoutedEventArgs e)
{
MessageBox.Show("This is the load event for this page");
}
}
If you really have a need to navigate from one XAML page to another, this will set you in the right direction: Silverlight Navigation Overview. I would say, however, that in a Silverlight app, if you're simply trying to display different content on the page, you don't generally follow the standard web navigation paradigm.
Application.Current.RootVisual = new MySecondPage();
where MySecondPage is the xaml page to which you want to navigate to.