I want to open a form, make a screenshot and close it.
So I tried the Shown Event, but this fired before everything is painted.
Since Shown is the last event fired (according to MSDN), what can I do?
I think just delaying isn't such a good idea in an event driven environment.
Any advice? Thx in adv.
<
{
InitializeComponent();
UpdateData();
this.Shown += new System.EventHandler(this.PrintForm_Shown);
this.ShowDialog();
}
private void PrintForm_Shown(object sender, EventArgs e)
{
DoPrintForm();
Close();
}
>
Related
I am developing a Windows UWP App with C++. I want to add a button that can either be left-clicked or right-clicked and do corresponding task.
The button works perfectly on normal devices with mouse. Unfortunately on touch screen, if users press-and-hold the button, both left-click and right-click events are triggered.
I am using "Click" to handle the left click event and "RightTapped" to handle the right click event. Any suggestion on how to disable the left-click event when users press-and-hold the button? Thank you!
The XAML code is short:
<Button x:Name="m_NewPageButton"
Content="New Page"
Height="48"
Width="199"
Click="OnClick"
RightTapped="OnRightClick"/>
And here's the cpp code:
void MainPage::OnClick()
{
// Left click task
}
void MainPage::OnRightClick()
{
// Right click task
}
Edit:
Thanks guys, the solution is to change the left click handler to , which will not be triggered by press-and-hold.
Hacky but works...
private bool rightClicked;
private async void Button_Click(object sender, RoutedEventArgs e)
{
if (rightClicked)
return;
await new MessageDialog("left").ShowAsync();
}
private async void Button_RightTapped(object sender, RightTappedRoutedEventArgs e)
{
rightClicked = true;
await new MessageDialog("right").ShowAsync();
rightClicked = false;
}
I'm guessing this is a flaw in the design.. :(
Actually... If you use the button's Tapped and RightTapped events it works as it should. So in this case just replace Clicked with Tapped and all is well... Then you can ignore the hack I put above.
You can use the Holding event to detect a tap and hold. Use the Tapped event for a single tap (or click). The Tapped event should only fire for touch on a quick tap and release. The mouse specific click will raise Tapped but a touch tap-and-hold will not.
I'm currently in the process of developing a SideDrawer for Xamarin.Forms, because at this point, the one from telerik is rather awful sideeffect-wise.
I know how to do this in WPF, since it's rather easy, but in Xamarin it's way different.
My code for the GestureFrame is pretty much the same as this.
I've used the sources at some github project/xamarin docs/XLabs to get started. At first it was going well, but as soon as i'm placing controls within the gestureframe i will not receive any events anymore, because the childcontrols appear to consume any touch/gesture events there are.
Does this ring a bell to anyone? Right now i'm not sure what i might be doing wrong for the control to behave this way
The Only Gestures that Xamarin Forms handles currently are Tap and DoubleTap these bubble up by default. For Android, Windows and presumably IOS each handle other gestures differently.
Quick Review of Event Handling in the Xamarin.Forms world:
On Android
Gestures are handled by the Renderer each renderer has a Touch event. Touch is raised in the renderer when a gesture occurs. By subscribing to the Touch event and intupreting the EventArgs you can determine what is happening on the screen. Now you could make all the determinations yourself of what the user is doing or use the Mono.Android.GestureDetector to make those decisions for you. GestureDetector requires a GestureListener which it notifies when it believes an event like a tap or double have occured. Your Gesture listener can then contain whatever code you want to respond to these events.
On Windows
Each native control determines for itself When an event has occurred and exposes a set of EventHandlers for those events. To respond to these events you create a custom renderer and subscribe to the events on the native controls that then execute your own code.
On IOS?
Don't know yet haven't got that far in my project https://github.com/Indiponics/IndiXam-Lib maybe someone else can give you that piece.
Bubbling up the Events
Lets look at a simple bubbling situation:
public class App : Application
{
public App()
{
// The root page of your application
MainPage = new ContentPage
{
Content = new Frame
{
Content =
new Label {
Text = "Hold Me, Thrill Me, Kiss Me"
}
}
};
}
}
Lets put some Custom Renderers together and look at whats happening. To start with we'll need a renderer for every control in the stack so in our case a Label Renderer and a Frame Renderer.
We'll Start with Windows:
[assembly: ExportRenderer(typeof(Label), typeof(myLabelCustomRenderer))]
[assembly: ExportRenderer(typeof(Frame), typeof(myFrameCustomRenderer))]
namespace App4.WinPhone
{
public class myFrameCustomRenderer:FrameRenderer
{
protected override void OnElementChanged(ElementChangedEventArgs<Xamarin.Forms.Frame> e)
{
base.OnElementChanged(e);
if(e.NewElement!=null)
{
this.Control.Hold += Control_Hold;
}
}
void Control_Hold(object sender, System.Windows.Input.GestureEventArgs e)
{
System.Diagnostics.Debug.WriteLine("Frame Held");
e.Handled = false;
}
}
public class myLabelCustomRenderer : LabelRenderer
{
protected override void OnElementChanged(ElementChangedEventArgs<Xamarin.Forms.Label> e)
{
base.OnElementChanged(e);
if (e.NewElement != null)
{
this.Control.Hold += Control_Hold;
}
}
void Control_Hold(object sender, System.Windows.Input.GestureEventArgs e)
{
System.Diagnostics.Debug.WriteLine("Label Held");
e.Handled = false;
}
}
}
Running this we find that
Bubbling actually occurs by default in windows. If we wanted we could turn off bubbling by changing
e.Handled = true;
In our Label Renderer and the frame would never get notified of the Hold Event.
Now For Android
On Android things get a bit messier. Again we'll create two renderers.
[assembly: ExportRenderer(typeof(Label), typeof(myLabelCustomRenderer))]
[assembly: ExportRenderer(typeof(Frame), typeof(myFrameCustomRenderer))]
namespace App4.Droid
{
public class myFrameCustomRenderer : FrameRenderer
{
protected override void OnElementChanged(ElementChangedEventArgs<Xamarin.Forms.Frame> e)
{
base.OnElementChanged(e);
if (e.NewElement != null)
{
this.Touch += myFrameCustomRenderer_Touch;
}
}
void myFrameCustomRenderer_Touch(object sender, Android.Views.View.TouchEventArgs e)
{
System.Diagnostics.Debug.WriteLine("You Touched My Frame");
e.Handled = false;
}
}
public class myLabelCustomRenderer : LabelRenderer
{
protected override void OnElementChanged(ElementChangedEventArgs<Xamarin.Forms.Label> e)
{
base.OnElementChanged(e);
if (e.NewElement != null)
{
this.Touch += myFrameCustomRenderer_Touch;
}
}
void myFrameCustomRenderer_Touch(object sender, Android.Views.View.TouchEventArgs e)
{
System.Diagnostics.Debug.WriteLine("You Touched My Label");
e.Handled = false;
}
}
}
If we run this it appears that everything works the same as windows we geta touch event in the label and a touch event in the Frame. The bubbling up appears to be automatic. It Gets messy when we attempt to disable bubbling. If we change
e.Handled=true;
in the Label Renderer and run the app again---
Touch fires twice IN THE LABEL RENDERER. Once for when we touch the screen and once for when we stop. If we set the labelrenderer's e.Handled=false; and set the Frame to true. Then the label touch fires followed by the Frame but only the Frame Fires the second time.
In addition if we remove e.Handled=false from both renderer and run the app we find that only the LabelRenderer's Touch event fires. Implying that the default for Handled appears to be true. If you do not set e.Handled=false in the renderer the event will fire in the LabelRenderer and not bubble up the stack to the FrameRenderer.
In Conclusion:
Bubbling works out of the box on Windows. On Android it doesn't work like you might expect. First you have to explicitly set the Handled=false in every child so the parent gets notification and even then only the Handler that Handled the event gets notified that the touch event ended the rest of the stack gets notified of the start but never knows its over.
I am building an application that minimizes to tray when the user clicks the close button (the cross on the upper right corner) using this code:
private void FrmTest_FormClosing(object sender, FormClosingEventArgs e) {
e.Cancel = true;
WindowState = FormWindowState.Minimized;
}
however, if I want to actually close the window on a button using Close() this handler is called and the form doesn't close.
How can I close my form / application now?
I fixed it (thought I checked this, but apparently, something went amiss while debugging).
You can use the CloseReason property to find out why the event is called. When the user clicks on the close button on the window, e.CloseReason is UserClosing, otherwise it is ApplicationExitCall:
private void FrmTest_FormClosing(object sender, FormClosingEventArgs e) {
if (e.CloseReason == CloseReason.UserClosing) {
e.Cancel = true;
WindowState = FormWindowState.Minimized;
}
}
Update when using Close() to close the form, the CloseReason will be the same and you should use a boolean as Hans Passant mentions in the comments. When using Application.Exit(), this CloseReason solution works.
In normal version of silverlight you can create an event handler by registering it by EventManager. Windows Phone 7 hasn't got that class.
My question is: How to create an event, which will be handled by the parent panels.
My scenario: I've created a custom class with some textbox in it. Foreach I've added my custom behavior, which raises when textblock is clicked. Behavior works like: "When this Textblock in custom control is clicked, please raise a custom event with my custom args (i want to pass them to the Custom Control itself (for example to specify to which VisualState change it)."
Can you help me how to handle my problem?
Could you provide sample code of what you are trying to do? it seems you want to create an event for when the TextBlock is clicked.
Add an event handler to the textblock:
public Event EventHandler<RoutedEventsArgs> TextClicked;
// Fire the event
private void OnTextClicked(object sender, RoutedEventArgs e)
{
if (TextClicked != null)
{
TextClicked(sender, e);
}
}
TextBlock.Click =+ OnTextBlockClicked;
private void OnTextBlockClicked(object sender, RoutedEventArgs e)
{
// Raise event
OnTextClicked(sender, e);
}
Something along those lines I think.
I create a button control and it shows up, but when clicked event does not fire, not sure if it could be because control gets greated after previous event in AJAX which fires fine.
Should only get executed once.
Any ideas would be appreciated, thanks.
Button btnCommentSave = new Button();
btnCommentSave.ID = "mySavebtnComments" ;
btnCommentSave.Text = "Publish";
btnCommentSave.BackColor = Color.Aquamarine;
phBlog.Controls.Add(btnCommentSave);
btnCommentSave.CommandArgument = row["ID"].ToString();
btnCommentSave.Click += new EventHandler(btnSave_Click);
protected void btnSave_Click(object sender, EventArgs e)
{
other code
}
You are not by any chance executing this code on Page_Load?
You have to make sure that this code is executed only once, otherwise the event won't fire.