This question already has answers here:
Triggering a button click through code
(6 answers)
Closed 4 years ago.
private void btnSend_Click(object sender, EventArgs e)
{
Dosomething();
}
private void Something(object sender, EventArgs e)
{
btnSend_click( how to write in here?? )
}
I want to implement btnSend_Click in other section(?), but i don't know how to do this. i want to implement this code without using UI.
If you just need to call the method btnSend_Click from the method Something, you can pick any of these:
private void Something(object sender, EventArgs e)
{
btnSend_click(this, EventArgs.Empty);
}
Or
private void Something(object sender, EventArgs e)
{
btnSend_click(sender, e);
}
It is all about naming, that is, giving the methods a good name.
First, you write the underlying method that does the actual work.
public class Someone
{
public void DoSomething()
{
Console.Beep(); //make a noise
}
}
At this point, no UI is involved, no button, no sender, no EventArgs.
Then
Call this method when the button is clicked.
private void btnSend_Click(object sender, EventArgs e)
{
new Someone().DoSomething();
}
Call this method from any other place.
class AnotherOne
{
private void DoAnotherThing()
{
new Someone().DoSomething();
}
}
I don't answer your question on how to call btnSend_click from anywhere by passing faked sender and EventArgs.
Because that is not a good idea to write such calls - before long you will be confused by the names even if the code was written by yourself.
Related
This question already has answers here:
WinForms: How to programmatically fire an event handler?
(4 answers)
Closed 2 years ago.
I am using C# in WinForms to use a trackbar as follows. At the beginning of the code I define the event handler:
this.trackBar1.Scroll += new System.EventHandler(this.trackBar1_Scroll);
And here is the implementation when one scrolls the trackbar:
private void trackBar1_Scroll(object sender, EventArgs e)
{
//do something...
}
So this works, but I need to call the above function from inside another event handler such as:
public void numericUpDown1_TextChanged(object sender, EventArgs e)
{
//what to do here to call trackBar1_Scroll ?
}
What could be done to call trackBar1_Scroll from inside numericUpDown1_TextChanged?
Very often you do not need the sender and e parameters. Therefore just create a parameterless method
private void DoSomething() // Hopefully with a better name
{
// do things ...
}
and then call it inside your event handlers.
private void trackBar1_Scroll(object sender, EventArgs e)
{
DoSomething();
}
public void numericUpDown1_TextChanged(object sender, EventArgs e)
{
DoSomething();
}
If you give the method a descriptive name, your code becomes easier to read. But of course you could as well just call the other event handler. The event handler is just a method after all
public void numericUpDown1_TextChanged(object sender, EventArgs e)
{
trackBar1_ValueChanged(sender, e);
}
Since both of these event handlers have the same signature (the same parameter list and return type), you could declare a single one and attach the same to both controls:
void HandleUpdates(object sender, EventArgs e)
{
// do things...
}
And assign it with
trackBar1.Scroll += HandleUpdates;
numericUpDown1.TextChanged += HandleUpdates;
You can also assign it in the properties window on the events tab. new System.EventHandler(...) is not necessary. C# does it automatically for you.
I was wondering if there was a more efficient way to format the following code:
private void nmudc1_Enter(object sender, EventArgs e)
{
SelectAllNumericalUpDownText(nmudc1);
}
private void nmudc1_Click(object sender, EventArgs e)
{
SelectAllNumericalUpDownText(nmudc1);
}
private void nmudc2_Enter(object sender, EventArgs e)
{
SelectAllNumericalUpDownText(nmudc2);
}
private void nmudc2_Click(object sender, EventArgs e)
{
SelectAllNumericalUpDownText(nmudc2);
}
And so on.
I apologize if this has been asked before or elsewhere, and I assume the answer is relatively simple. Unfortunately, I have been unsuccessful in finding a suitable answer thus far.
I have thought about trying to put in in an array, or an object, but I really just have no idea how I would go about doing this to a function like this.
Thank you.
You can create only one event function, And send the sender as parameter to the SelectAllNumericalUpDownText function.
Register all events to this function:
nmudc1.Click += nmudc_Event;
nmudc1.Enter += nmudc_Event;
nmudc2.Click += nmudc_Event;
nmudc2.Enter += nmudc_Event;
Generic implementation to the function:
private void nmudc_Event(object sender, EventArgs e)
{
SelectAllNumericalUpDownText(sender as <TYPE>);
}
Since all event handlers in your code sample have the same method signature, you can simply use the same method to handle all the events:
private void NumericUpDown_event(object sender, EventArgs e)
{
SelectAllNumericalUpDownText(sender as NumericUpDown);
}
This is assuming, of course, that your sender object is actually a NumericUpDown.
You could use the following alternative:
private void NumericUpDown_Event(object sender, EventArgs e)
{
if (!(sender is <controltype> nump))
return;
SelectAllNumericalUpDownText(nump);
}
By this you do not call the method if the sender is not of type < controltype >. Therefor you already used the generic EventArgs class you can subscript the Enter/Click event to this method.
Is it a good practice to call Page_Load function in another function like this. It's working but I don't know if i should do this
public bool myButtonClick(object sender, EventArgs e){
Page_Load(this, null);
}
You can do this, but you shouldn't. And it is very easy to prevent this:
In your Page_Load, call a method that does the actual work in the method now. Then call that method from myButtonClick:
public void Page_Load(object sender, EventArgs e)
{
this.SomeMethod();
}
public void myButtonClick(object sender, EventArgs e)
{
this.SomeMethod();
}
private void SomeMethod()
{
// the actual code now in Page_Load
}
You see, nice and clean and reusable too.
So I have a form where I want to change the position of a trackbar and trigger the trackbar_scroll event after I click on a label. So far, clicking on the label changed the value of the trackbar, thats easy:
private void label4_Click(object sender, EventArgs e)
{
trackBar1.Value = 0;
}
private void trackBar1_Scroll(object sender, EventArgs e)
{
if (trackBar1.Value == 0)
{
try
{
//code...
}
catch
{
MessageBox.Show("Error occured");
}
}
}
How do I call the trackBar1_scroll(..) event from within the label click?
Try calling it directly. You just have to supply the parameters yourself:
trackBar1_Scroll(trackBar1, EventArgs.Empty);
or simply
trackBar1_Scroll(null, null);
if the parameters are not being utilized.
Another approach you could take, aside from #LarsTech answer (which is absolutely correct), would be to refactor your code to reduce the need to supply empty parameters. Since you're not actually using the EventArgs or referencing the sender directly, given your example above, you could do something like the following:
private void DoSomething(int value)
{
...
}
private void trackBar1_Scroll(object sender, EventArgs e)
{
DoSomething(trackBar1.Value);
}
private void label4_Click(object sender, EventArgs e)
{
DoSomething(...);
}
It always feels like code smell to me, when you call an event handler with empty parameters, simply to execute code which you could otherwise abstract out.
I want to call btnDisconnect_Click within btnExit_Click.
private void btnDisconnect_Click(object sender, EventArgs e)
{
//does something
}
private void btnExit_Click(object sender, EventArgs e)
{
//I want to call btnDisconnect_Click. What line of code should I use here?
}
Usually in cases like these I make my click handlers only call another function and pass in appropriate arguments:
private void btnDisconnect_Click(object sender, EventArgs e)
{
DoDisconnect();
}
private void DoDisconnect()
{
...
}
Then I can call that same function from wherever:
private void btnExit_Click(object sender, EventArgs e)
{
DoDisconnect();
}
This way your "disconnect" logic is gummed up by taking dummy arguments that don't actually affect the disconnect behavior in any way.
It also means you can start factoring out view logic from forms.
That depends on if you are using the arguments passed to the event handlers
You could yust call it using nulls
Something like
private void btnDisconnect_Click(object sender, EventArgs e)
{
//does something
}
private void btnExit_Click(object sender, EventArgs e)
{
//I want to call btnDisconnect_Click. What line of code should I use here?
btnDisconnect_Click(null,null);
}
They're just methods. Just call it. You'll need to provide whatever event arguments btnDisconnect_Click is expecting (which is probably nothing). So the simplest thing is:
private void btnExit_Click(object sender, EventArgs e)
{
btnDisconnect_Click(this, EventArgs.Empty);
}
This will pass the current form/window/whatever it is as the sender, and an EventArgs object with no data.
You can call it just as you have it listed. The this below isn't necessary but it puts context on the code:
private void btnExit_Click(object sender, EventArgs e)
{
//I want to call btnDisconnect_Click. What line of code should I use here?
this.btnDisconnect_Click(null, null);
// If you need to have sender as something you can always put
// this in directly
this.btnDisconnect_Click(this.btnDisconnect, new System.EventArgs());
}
I'm going to make an assumption here and say that what you're trying to do is call a Disconnect (perhaps a network resource) for both the disconnect and exit buttons. Instead of calling one event handler method from the other you may want to refactor the disconnect event handler's code into a separate method. Then call that method from both handlers. For example:
private void Disconnect()
{
//Disconnect here
}
private void btnDisconnect_Click(object sender, EventArgs e)
{
//do some other stuff here
Disconnect();
}
private void btnExit_Click(object sender, EventArgs e)
{
//do some other exit stuff here
Disconnect();
}
This makes your code much cleaner and saves you from having to call one event handler from another. This begins to separate your view logic from the rest of your program's logic, which is much more desirable and much easier to maintain in the long run. For instance you may want a separate controller for handling the network resource, instead of embedding it into the view's logic.
In the simplest case you can just call the btnDiconnect_Click directly as follows:
private void btnDisconnct_Click(Object sender, EventArgs e)
{
//Does Something
}
private void btnExit_Click(Object sender, EventArgs e)
{
//Call btnDisconnect_Click()
btnDisconnect_Click(sender, e);
}
You could just call the method passing in valid parameters.
btnDisconnect_Click(btnDisconnect,new EventArgs());
However you might want to consider refactoring out the code in btnDisconnect into a new method and calling that instead:
private void doSomething()
{
//....
}
private void btnDisconnect_Click(object sender, EventArgs e)
{
doSomething();
}
private void btnExit_Click(object sender, EventArgs e)
{
doSomething();
}
{// this is probably your constructor
.
public delegate void MyCustomHandler(object sender, EventArgs e);
.
MyCustomHandler myCustomHandler = new MyCustomHandler(); //you can do more in your delegates constructor, members etc
myCustomHandler += btnExit_Click;
myCustomHandler += btnDisconnect_Click;
}
private void btnDisconnect_Click(object sender, EventArgs e)
{
// do Something
}
private void btnExit_Click(object sender, EventArgs e)
{
// do Something
}
//And wherever you need to invoke these, you do
myCustomHandler(object sender, EventArgs e);