I has rey use VS 2015 with xamarin forms to create a cross platform project. I add the xaml page which contain a text box and button. In the code behind, I has code as below
public Inno()
{
InitializeComponent();
btntest.Clicked += Btntest_Clicked;
}
Private void Btntest_Clicked(object sender, EventArgs e)
{
if(string.IsNullOrEmpty(Name.Text))
{
return;
}
}
When I run the android simulator to test the page, it fire the constructor. But when I clicke the button, it not fire the click event. Anything goes wrong? Please help. Thanks
Theres a few things you can try:
hook up the event handler in the xaml, see if that works - because you are subscribing to the event in the constructor this shouldn't make a difference functionality wise.
Edit: to do this, in your xaml:
<Button Clicked="buttonClicked" />
and Press tab when intellisense prompts you to create a new handler.
as #hankide said - set a breakpoint and make sure it isn't actually entering it and that the problem isn't the code inside the event handler.
You need to make sure that your btntest object has been properly mapped to the button on the XAML side of things. By default, XAML objects don't have "names" as you may be accustomed to in WinForms or WebForms and need to have a name property assigned to them. For me, I typically have my buttons marked up as:
<Button x:Name=btntest Text="Click Me></Button>
Then in the code behind I have to find the button by name in order to wire up the event:
var testButton = this.FindByName<Button>("btntest");
testButton.Clicked += Btntest_Clicked;
From there everything works as expected.
Try this:
btntest.Clicked += new EventHandler(Btntest_Clicked);
Thanks everyone for the answer...not sure why I close the solution and re-open it, it work fine.
Related
So, I would double click here on my designer
and it should create me the code, but well it doesn't. And there is no value changed event in the events either.
So if anyone knows how to fix this, it would be nice. (I doubt it) so how would I get around this? How would I go on about creating the code myself that should be created when I double click on it?
Click the form or control that you want to create an event handler for.
In the Properties window(F4), click the Events button
In the list of available events, click the event that you want to create an event handler for.
In the box to the right of the event name, type the name of the handler and press ENTER.
Add the appropriate code to the event handler.
To create an event handler in the code editor
Switch to the code editor by using one of the following techniques:
Create a new method like:
private void buttonName_Click(object sender, EventArgs e) { ... }
In the file YourFormName.Designer.cs find your button and add
this.buttonName.Click += new System.EventHandler(this.buttonName_Click);
Using VS2013 it was possible, at least with VB.NET, to double click on a control and then the default event would show up in the code file.
Above this there was a pull down list of the other possible events for this control.
Now I'm working in VS2015 and in C#, but that list is not there.
I can still double click on a control to get the default event, but I cannot add another event. I don't think I'm supposed to edit the designer file.
How do I do this now?
Do I need to add events in the code file now?
for example I want to be able to drop a file on my windows application.
So somewhere I need to add the event for this.
Winforms :
Wpf:
To see the properties window:
Using VS2013 it was possible, at least with VB.NET, to double click on
a control and then the default event would show up in the code file.
Above this there was a pull down list of the other possible events for
this control.
This is known as the Navigation Bar. You can toggle it on/off in Tools --> Options --> Text Editor --> {Select Language} --> Navigation Bar.
BUT...the Navigation Bar behaves differently in C# than it does in VB.Net. It won't do what you want in C#, sorry!
To wire up an event using the IDE in C#, you have to first select the thing in question, then go to the Properties Pane and switch it to the Events view with the "Lightning Bolt" icon as Empereur Aiman has shown in his post.
C#, however, can do something that VB.Net cannot. With C#, you can wire up an event by writing a line of code in the editor and have the IDE generate the event stub for you. For instance, in the snippet below, a dynamic button is being created:
Button btn = new Button();
If you want to wire up its Click() event, you'd type in:
btn.Click +=
After the equals sign = is typed, you'd press {Tab} and the event stub will be generated for you:
private void Btn_Click(object sender, EventArgs e)
{
throw new NotImplementedException();
}
If you keep the mouse on the Button key word in xaml code and then click on the lightning icon, you will be able to see the click event.
What I'm trying to do is get my winform to display a debug line when ever I click in my winform. However, when I do, nothing happens. I know how to get a button / other click event to happen. But what I need is to be able to click anywhere within my winform.
I've googled this for the past hour but can't see what I'm doing wrong. As far as I'm aware, this code should be correct in detecting a mouse click. This method is held withing the form1.cs class:
private void mouseClick(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
Trace.WriteLine("Mouse clicked");
}
I've tried setting brake points, but these don't get triggered either. What is it I'm doing wrong?
Sorry for the stupidly newbie question, but I am very new to winform programming.
How to add the EventHandler:
public Form1()
{
InitializeComponent();
// This line should you place in the InitializeComponent() method.
this.MouseClick += mouseClick;
}
Using the editor built-in to Visual Studio:
Go to the properties window (if you don't see it, press Alt + Enter).
Select the events icon (looks like lightning).
Double-click on the empty ComboBox to the right of Click.
You'll be taken to an empty method where you can put your code.
The method itself is correct. I think your actual problem is: you haven't added this method to MouseClick events.
In C# – and most other languages too – event is handled by an event handler. Windows forms and controls have events for all the events happening in your controls, such as OnClick or OnResize.
You can append methods to these events, and the methods will automatically get called when the actual event happens. Simply add the following line to your form's constructor, Form_Load-method, InitializeComponent-method, or such:
this.MouseClick += mouseClick;
Now when ever MouseClick event happens, your method mouseClick will be called automatically.
I would recommend reading Events C# Programming Guide. You need to add an event handler like so:
form1.MouseClick += mouseClick;
I have a textbox in Form and i want to detect when the text has changed but the code I have found is giving me no joy.
I am probably missing something in the proporties or something you have to define before.
Here is my code:
private void tbxparkingTimesS1_TextChanged(Object sender, EventArgs e)
{
MessageBox.Show("You are in the ToolStripItem.TextChanged event.");
}
Thanks for any help with this trivial problem.
To wire the TextChanged event to a particular method inside your code do the following
Click on the TextBox inside your form
Open the properties windows (press F4 or menu View -> Property Window )
Select the event page (lightning icon)
Double click on the TextChanged property line
Insert your code inside the template build for you by Visual Studio
Have you assigned the event handler to the textbox?
Normally this will be done "behind the scenes" by Visual Studio - with the result being an additional line of code in your .designer file.
Something like:
this.tbxparkingTimesS1.TextChanged += new System.EventHandler(tbxparkingTimesS1_TextChanged);
(It['s been a while since I've done webforms - so that might be slightly off)
Double Click on Text box it will generate text change event for you.
private void tbxparkingTimesS1_TextChanged(object sender, EventArgs e)
{
// implement your code here.
}
When you double click VS will create event handler in your designer.cs file as bellow
this.tbxparkingTimesS1.TextChanged += new System.EventHandler(this.tbxparkingTimesS1_TextChanged);
You can do the same by using property window events or create event on code behind.
Could anyone please explain what and how this code below is doing/working?
RoleEnvironment.Chaning += RoleEnvironmentChaning;
private void RoleEnvironmentChanaing(object sender, RoleEnvironmentchaningnEventArgs e)
{
......
}
basically, if you could walk me through how event handling works in c#.net will be greatly appreciated.
Thanks.
Let's forget about C# for a second and think about the following scenario.
You have a button on the screen that you want the user to click, you don't know when the user will click the button and neither do you want to check constantly if the user has clicked the button. What you want to do is run a bit of custom code when the user does eventually click on a button.
Welcome to events or delegates.
Let's take a look at the button.
The Button has a Click event that you can hook your custom code onto.
i.e.
//This happens in the designer
Button button = new Button();
button.Click += new EventHandler(YourMethod);
Your method will now be called once the button has been clicked.
What happens on Click of the button? Someone will check whether or not there are subscribers to the event
if(Click != null)
{
Click(this, someEventArguments);
}
Basically that's saying: whenever the RoleEnviroment decided to trigger the "changing" event, call that method. (I assume it should be Changing rather than Chaning or Chanaing as per your code.)
In other words, events in C# are an implementation of the publisher/subscriber or observer pattern.
See my article on events and delegates for more information.
Some first page search results:
http://www.codeproject.com/KB/cs/csevents01.aspx
http://www.c-sharpcorner.com/UploadFile/ddutta/EventHandlingInNetUsingCS11092005052726AM/EventHandlingInNetUsingCS.aspx
http://msdn.microsoft.com/en-us/library/aa645739%28VS.71%29.aspx