I have a lot of buttons in my project. To make the program I shorter need to get every click of a button to the same "Button_click" method. Is this possible?
Thanks
Just use the same event handler for all the buttons. In code, this would be:
button1.Click += HandleButtonClick;
button2.Click += HandleButtonClick;
etc
It should be possible to do in the designer too.
If these are buttons in different forms, you'll need to either have a static handler method somewhere, or each form will need a reference to whatever class has the handler method. You may well need to add these handlers in code, rather than using the designer.
Yes - it's perfectly possible.
You don't say whether you're WinForms or WPF but the basic way is to create a private method that's the handler and then call that from each button handler:
private void ButtonHandler(some arguments)
{
}
private void OnButton1Click(object sender, EventArgs e)
{
ButtonHandler(some arguments);
}
However, you can just subscribe the same handler to each button's click event:
Button1.Click += ButtonHandler;
Button2.Click += ButtonHandler;
Or set these from the designer - just pick the existing method from the drop-down list rather than creating a new handler.
With WPF you can quite easily bind each button click to the same handler in XAML:
<Button x:Name="Button1" Click="ButtonHandler" ... />
<Button x:Name="Button2" Click="ButtonHandler" ... />
Again the designer gives you the choice of selecting an existing handler as well as creating a new one.
Yes, it's possible, just select the method you need in your Events tab of Properties Window designer (you can show it from the main menu: View -> Properties Window):
Or do it manually in <Formname>.Designer.cs file:
this.button1.Click += new System.EventHandler(this.button1_Click);
//...
this.button2.Click += new System.EventHandler(this.button1_Click);
Also, if you want to perform slightly different actions depenging of which button was pressed and still only use one method, use sender argument. Its value will always be a reference to the button that was clicked, so you can do some logic by looking at button's Name or Tag properties:
private void button1_Click(object sender, EventArgs e)
{
Button btn = (Button)sender;
switch((int)btn.Tag) {
case 1:
// action 1
break;
case 2:
// action 2
break;
}
}
Still, you should be careful with this and see if it really gives you any benefits to share an event handler instead of creating separate handlers for different buttons.
Related
I am creating a windows store application for which I have to program computer to perform a click on different button after the user has clicked a button. I have Implemented the logic for computer click. But the code b1.Click += btnClick; doesn't help me to perform a click event on the b1 button. Please tell how to do so. And please mention the namespace too if any extra to be used.
private void button6_Click(object sender, EventArgs e)
{
//just make sure your button initialized on form!!
this.button7.Click += new EventHandler(button7_Click);
EvenArgs ee = new EventArgs();
button7_Click(this.button7, ee); //this will fire button event!
}
b1.Click += btnClick; should work for subscribing to a button click event. When the user taps/clicks on the button, the btnClick handler will be fired.
Now, if I read your question properly, are you asking to perform a button click? If so, you can call the event handler btnClick yourself: btnClick(this, null);
b1.Click += btnClick;
b2.Click += btn2Click;
b3.Click += btn3Click;
void btnClick(...)
{
...
// perform a click on different button after the user has clicked a button.
btn2Click(...);
btn3Click(...);
}
As andrew says you should be able to add multiple events to an event handler like so:
b1.Click += btnClick1;
b1.Click += btnClick2;
For that^ you might want to check if the event handler is already attached to the event like this question explains.
Also as mentioned by both Andrew and Nagaraj you can just call the function from the event handler like:
btnClick2(this, null);
and it will execute the code ( albeit with a little less control since you won't be able to remove it from the click handler without a bunch of extra effort ).
Option three would be to create a function with the desired functionality you want for both buttons and just call that from both the handlers instead of making another button "click". It's more modular and obvious what is happening in your code then.
Through Visual Studio you can easily create a method for an event (button click, etc). Is there a way to create a method for multiple events, like a method that would run any time one of three buttons were clicked, or one of many textboxes were typed in?
Once you've created the method once you should be able to use it for any other event that has a similar signature.
From the Designer, don't double-click the method but instead drop down the list for any existing event handler that can be assigned to your chosen event.
Like #lcfseth notes, you can identify which particular control sent the message via the object sender argument.
Yes ,you can bind many events to the same method (events of the same signature)
firstEvent += MyMethod;
secondEvent += MyMethod
You can assign the same handler to Click events of multiple controls. sender points to the control that caused the event.
When you bind a function to an object's event you're actually passing a delegate (i.e. a pointer-to-function) to its event handler. You can bind the same function to as many objects' event handlers as you want, as long as the required delegate's signature corresponds.
Button1.Click += new EventHandler(this.AnyButton_Click);
Button2.Click += new EventHandler(this.AnyButton_Click);
Button3.Click += new EventHandler(this.AnyButton_Click);
In case you need to run specific operations on the "sender" object depending on which button was clicked pay attention that the function's argument "sender" is the button you clicked so if you need to work on the button object remember to unbox it to its specific class (i.e. cast it to Button or whatever its type is).
void AnyButton_Click(Object sender, EventArgs e)
{
Button clickedButton = (Button)sender; // unbox the sender
MessageBox.Show("You just clicked button " clickedButton.Text);
}
(MSDN)
I'm creating buttons by code inside a FlowLayoutPanel and I can't create a click event for each one of the created buttons. I need some help cause i'm stuck on this.
You can just subscribe to each button's Click event as you create them.
For example:
Button newButton = new Button();
// Setup button...
newButton.Click += this.ClickHandler;
Then, somewhere else:
private void ClickHandler(object sender, RoutedEventArgs e)
{
// Do something here
}
The other, potentially more elegant, option would be to bind the Button's Command to an ICommand. You could also set it's CommandParameter in order to pass additional, button specific, information.
Here's the solution, Manage controls at Runtime.
I have a GUI app, that has a button added. Within several plugin dll's, a new button is created and needs to be added to the GUI in place of the existing one.
Is there a way to simply say ButtonA = ButtonB? Or do I have to remove the button from the GUI at runtime and then add the new one?
Thanks.
Or you can just link it to another handler, something like:
your old Click event handler
private void ButtonA_Click(object sender, EventArgs e)
{
//Do sth
}
your new Click Event handler (like if you create a new button)
private void ButtonB_Click(object sender, EventArgs e)
{
//Do sth
}
then you need to remove the first handler and add your new handler:
ButtonA.Click -= this.ButtonA_Click;
ButtonA.Click += new EventHandler(ButtonB_Click);
You button is added to some parent (the Form for example). That means you have to remove the original button from the Form's Controls collection, and add the new button. Or, you can replace the button inside the Controls collection.
Let's say after iterating through the collection, you find that the button is the 5'th element, you can do something like this:
this.Controls[4] = ButtonB;
I'm not 100% sure if this means that you will have to manually invalidate the screen to update the GUI. In that case call ButtonB.Invalidate();
Copy properties you are interested in from the first button to the second that is created, and then either remove first button from the Controls collection or set .Visible to false.
As for events, you'll have problem there, because you'll have to call old button event handlers manually - there is no way in .NET to read OnClick (or any other event) subscribers.
I have a TextBox on a WinForm and I want to execute some code every time someone presses a key inside of that TextBox. I'm looking at the events properties menu, and see the KeyDown event, but don't know how to add code to it.
You need to add an event handler for that event. So in the properties menu, double-click on the field beside the KeyDown event and Visual Studio will create an event handler for you. It'll look something like this:
private void textBox1_KeyDown(object sender, KeyEventArgs e)
{
// enter your code here
}
You can also subscribe to events yourself without using the Properties window. For example, in the form's constructor:
textBox1.KeyDown += HandleTextBoxKeyDownEvent;
And then implement the event handler:
private void HandleTextBoxKeyDownEvent(object sender, KeyEventArgs e)
{
// enter your code here
}
These answers will have visual studio generate the event and bind it behind the scenes in the Designer.cs file.
If you want to know how to bind events yourself, it looks like this.
MyTextBox.KeyDown += new KeyEventHandler(MyKeyDownFunction)
private function MyKeyDownFunction(object sender, KeyEventArgs e) {
// your code
}
If done this way, the new KeyEventHandler() part is optional. You can also use lambdas to avoid boilerplate code.
MyTextBox.KeyDown += (s, e) => {
// s is the sender object, e is the args
}
Doubleclick the textfield next to it.
I assume you are in Visual Studio. One way would be to double click on the empty textbox on the right of the KeyDown event: VS will generate the code for you.
You need to add a handler to the event.
Double-click the KeyPress event in the textbox's Properties window to make Visual Studio generate an event handler in the code file.
You can then put any code you want to inside the event handler function. You can check which key was pressed by writing e.KeyCode.