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How to call common Method to multiple Events

Hello I have this code:
private void txtNumero_KeyDown(object sender, KeyEventArgs e)
{
CercaCliente();
}
private void txtNote_KeyDown(object sender, KeyEventArgs e)
{
CercaCliente();
}
private void txtNominativo_KeyDown(object sender, KeyEventArgs e)
{
CercaCliente();
}
How can I write this code in better mode? Thanks

there are two approaches you can choose from, and it depends what type of effort you are ready to do...
first when you bind the event there itself call the method rather than creating handler method for each.
Currently, you are doing -
txtNumero.KeyDown += new txtNumero_KeyDown;
..
..
txtNote.KeyDown += new txtNumero_KeyDown;
then in your method you are calling this common method 'CercaCliente()'. you can directly use func delegate to call you common method. e.g.
txtNumero.KeyDown += (o,e)=>CercaCliente();
..
..
txtNote.KeyDown += (o, e)=>CercaCliente();
OR
You can create custom control, derived from textbox, and there you can handle it.

Add this common method
private void HandlerMethod(object sender, EventArgs e)
{
CercaCliente();
}
Then inside your form load Attach this handler method to all events
this.txtNominativo.KeyDown += HandlerMethod;
this.txtNote.KeyDown += HandlerMethod;
this.txtNumero.KeyDown += HandlerMethod;

How to call treeView.SelectedItemChanged programmatically

In my program I would like to call to a SelectedItemChanged event using c# code-behind, I am just unsure about what to pass as parameters. This is for a TreeViewItem.
//Gets selected item in TreeView
private void TreeOne_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
{
MainWindowViewModel.SelectedItem = e.NewValue as TreeViewItem;
}
//I'm calling the SelectedItemChanged event from a RightButtonDown event
private void TreeOne_MouseRightButtonDown(object sender, MouseButtonEventArgs e)
{
TreeOne_SelectedItemChanged(/* What would go here? **/);
}
Also, when I try to build this I receive this compiler error that pretty much led to this question...
No overload for method TreeOne_SelectedItemChanged takes '0' arguments
I'm hoping that this is an easy question, but if I have not provided enough information, or haven't been clear enough please let me know.

Adding to #Bart Friederichs' answer and assuming that you have a reference to your TreeView, you could add the following method:
private void SetSelectedItem()
{
MainWindowViewModel.SelectedItem = TreeOne.SelectedItem;
}
Then you can simply call this from wherever you like:
private void TreeOne_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
{
SetSelectedItem();
}
private void TreeOne_MouseRightButtonDown(object sender, MouseButtonEventArgs e)
{
SetSelectedItem();
}

The usual design pattern would be to call some kind of processing method, and not to "manually" fire events:
private TreeOne_SelectedItemChaned(object sender,
RoutedPropertyChangedEventArgs<object> e) {
processChange();
}
Then, from withing your code, you just call processChange(), no need to call TreeOne_SelectedItemChanged.

try to call
TreeOne_SelectedItemChanged(null, null);

Trigger control's event programmatically

Assume that I have a WinFoms project. There is just one button (e.g. button1).
The question is: is it possible to trigger the ButtonClicked event via code without really clicking it?

Button controls have a PerformClick() method that you can call.
button1.PerformClick();

The .NET framework uses a pattern where for every event X there is a method protected void OnX(EventArgs e) {} that raises event X. See this Msdn article. To raise an event from outside the declaring class you will have to derive the class and add a public wrapper method. In the case of Button it would look like this:
class MyButton : System.Windows.Forms.Button
{
public void ProgrammaticClick(EventArgs e)
{
base.OnClick(e);
}
}

You can just call the event handler function directly and specify null for the sender and EventArgs.Empty for the arguments.
void ButtonClicked(object sender, EventArgs e)
{
// do stuff
}
// Somewhere else in your code:
button1.Click += new EventHandler(ButtonClicked);
// call the event handler directly:
ButtonClicked(button1, EventArgs.Empty);
Or, rather, you'd move the logic out of the ButtonClicked event into its own function, and then your event handler and the other code you have would in turn call the new function.
void StuffThatHappensOnButtonClick()
{
// do stuff
}
void ButtonClicked(object sender, EventArgs e)
{
StuffThatHappensOnButtonClick();
}
// Somewhere else in your code:
button1.Click += new EventHandler(ButtonClicked);
// Simulate the button click:
StuffThatHappensOnButtonClick();
The latter method has the advantage of letting you separate your business and UI logic. You really should never have any business logic in your control event handlers.

Yes, just call the method the way you would call any other. For example:
private void btnSayHello_Click(object sender, EventArgs e)
{
MessageBox.Show("Hello World!");
}
private void btnTriggerHello_Click(object sender, EventArgs e)
{
btnSayHello_Click(null, null);
}

button1.PerformClick();
But if you have to do something like this maybe it's better to move the code you have under the event on a new method ?

Why don't you just put your event code into a Method. Then have the Event execute the method. This way if you need to execute the same code that the Event rises, you can, but simply just calling the "Method".
void Event_Method()
{
//Put Event code here.
MessageBox.Show("Hello!");
}
void _btnSend_Click(object sender, EventArgs e)
{
Event_Method();
}
void AnotherMethod()
{
Event_Method();
}
Make sense? Now the "Click" event AND anywhere in code you can trigger the same code as the "Click" event.
Don't trigger the event, call the method that the event calls. ;)

In most cases you would not need to do that. Simply wrap your functionality in functions related to a specific purpose (task). You call this function inside your event and anywhere else it's needed.
Overthink your approach.

I recently had this problem where I wanted to programatically click a button that had multiple event handlers assigned to it (think UserControl or derived classes).
For example:
myButton.Click += ButtonClicked1
myButton.Click += ButtonClicked2;
void ButtonClicked1(object sender, EventArgs e)
{
Console.WriteLine("ButtonClicked1");
}
void ButtonClicked2(object sender, EventArgs e)
{
Console.WriteLine("ButtonClicked1");
}
When you click the button, both functions will get called. In the instances where you want to programmatically fire an event handler for a function from a form (for example, when a user presses enter in a Text field then call the InvokeOnClick method passing through the control you. For example
this.InvokeOnClick(myButton, EventArgs.Empty);
Where this is the Form instance you are in.

use a for loop to call the button_click event
private void btnadd_Click(object sender, RoutedEventArgs e)
{
for (int i = 0; i <= 2; i++)
StuffThatHappensOnButtonClick();
}
void StuffThatHappensOnButtonClick()
{
........do stuff
}
we assume at least one time you need click the button

Best Practice with Common Event Handling

In a WinForms solution, you have multiple controls of the same type. You need to add an event handler to each of the control and at the current time the event handler will be doing the same thing. You do not expect there to be difference between them down the road any reason.
eg:
ScheduledPatientsGrid.ProcessGridKey += ScheduledPatientsGrid_ProcessGridKey;
RecentPatientsGrid.ProcessGridKey += RecentPatientsGrid_ProcessGridKey;
RecentPatientsGrid.ProcessGridKey += RecentPatientsGrid_ProcessGridKey;
...
private void ScheduledPatientsGrid_ProcessGridKey(object sender, KeyEventArgs e)
{
...
}
private void RecentPatientsGrid_ProcessGridKey(object sender, KeyEventArgs e)
{
...
}
private void PatientsGrid_ProcessGridKey(object sender, KeyEventArgs e)
{
...
}
Now is it better to sharing an single Event Handler between the different events as shown below or use different ones like in the code sample shown above?
ScheduledPatientsGrid.ProcessGridKey += ProcessGridKey;
RecentPatientsGrid.ProcessGridKey += ProcessGridKey;
RecentPatientsGrid.ProcessGridKey += ProcessGridKey;
private void ProcessGridKey(object sender, KeyEventArgs e)
{
...
}
In the following page, Microsoft seems to suggest that sharing is better, however I notice that they have not updated it since .NET 2.0 (ie: Visual Studio 2008)
http://msdn.microsoft.com/en-us/library/4ac48519%28v=vs.90%29.aspx
Is there a Guide that makes a best practices recommendation in this case?

I would absolutely use the same method. What possible benefit is there to having multiple methods which do exactly the same, none of which is named to say what it does?
Personally I abhor the source_EventName convention that Visual Studio spawns. I prefer to give my event handler methods meaningful names which say what they do. Then when you look down the event handler list in the designer, you can see that when a button is clicked, X will happen rather than "the button's click event handler will be called" which is useless.
Alternatively, use lambda expressions to subscribe to the events and call meaningful methods with meaningful parameters. (The sender and args are often useless for event handlers.)

In this case, I usually have them wrap a common method, but I keep their event handlers named per usage. This allows me to easily unit test the method and (usually) reduce the needed parameters, and any errors in the stack trace will be very readable as to which grid the process failed for:
ScheduledPatientsGrid.ProcessGridKey += ScheduledPatientsGrid_ProcessGridKey;
RecentPatientsGrid.ProcessGridKey += RecentPatientsGrid_ProcessGridKey;
RecentPatientsGrid.ProcessGridKey += RecentPatientsGrid_ProcessGridKey;
...
private void ScheduledPatientsGrid_ProcessGridKey(object sender, KeyEventArgs e)
{
ProcessGridKey(e.Key);
}
private void RecentPatientsGrid_ProcessGridKey(object sender, KeyEventArgs e)
{
ProcessGridKey(e.Key);
}
private void PatientsGrid_ProcessGridKey(object sender, KeyEventArgs e)
{
ProcessGridKey(e.Key);
}
private void ProcessGridKey(Key e)
{
...
}
Your mileage may vary depending on what the shared method does, or the parameters passed in. (For example, in my above sample, I duplicate the pulling of the Key from the KeyEventArgs.

I prefer sharing, if the logic gets out of hand you can always just use the single event as a router to the correct method like...
private void ProcessGridKey(object sender, KeyEventArgs e)
{
if (sender is x)
xmethod();
if (sender is y)
ymethod(); //etc
}
I'm aware this syntax doesn't quite make sense as the sender will always be the same object in OP example, but you get the idea.

How do I call an event method in C#?

When I create buttons in C#, it creates private void button_Click(object sender, EventArgs e) method as well.
How do I call button1_click method from button2_click?
Is it possible?
I am working with Windows Forms.

How do I call button1_click method
from button2_click? Is it possible?
Its wholly possible to invoke the button's click event, but its a bad practice. Move the code from your button into a separate method. For example:
protected void btnDelete_OnClick(object sender, EventArgs e)
{
DeleteItem();
}
private void DeleteItem()
{
// your code here
}
This strategy makes it easy for you to call your code directly without having to invoke any event handlers. Additionally, if you need to pull your code out of your code behind and into a separate class or DLL, you're already two steps ahead of yourself.

// No "sender" or event args
public void button2_click(object sender, EventArgs e)
{
button1_click(null, null);
}
or
// Button2's the sender and event args
public void button2_click(object sender, EventArgs e)
{
button1_click(sender, e);
}
or as Joel pointed out:
// Button1's the sender and Button2's event args
public void button2_click(object sender, EventArgs e)
{
button1_click(this.button1, e);
}

You don't mention whether this is Windows Forms, ASP.NET, or WPF. If this is Windows Forms, another suggestion would be to use the button2.PerformClick() method. I find this to be "cleaner" since you are not directly invoking the event handler.

You can wire up the button events in the ASPX file code.
The button tag will wire the events like this:
<asp:Button Text="Button1" OnClick="Event_handler_name1" />
<asp:Button Text="Button2" OnClick="Event_handler_name1" />
Just wire the OnClick= to your handler method for button1

You can bind same handler for the event of both buttons