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
Related
Hi StackOverflow Community,
I have this code on CodeBehind:
protected void Btn_Search_Function(object sender, EventArgs e)
{
GV_Results.PageIndex = 0;
GV_Results.DataBind();
hdnSelectedTab.Value = "1";
}
This code is executed when I click a LinkButton. I want to call this function when another method (in the same page) finishes executing.
But I don't know what arguments to pass as object sender and EventArgs e. What is the best approach to achieve this?
Thank you in advance,
Best regards.
Ok so after 5 minutes I had the idea of creating a third method that would be called both by the function that is called when I click the LinkButton, and by the method I want to execute the same code.
I'm open to better ways of achieving this.
So, it is has follows:
protected void Btn_Search_Function(object sender, EventArgs e)
{
SearchFunction();
}
private void SearchFunction()
{
GV_Results.PageIndex = 0;
GV_Results.DataBind();
hdnSelectedTab.Value = "1";
}
If you have a button called Btn_Search and you have created an event handler for the button click event Btn_Search_Click(object sender, EventArgs e).
then, in your another method you can call like:
public void my_function()
{
//This simulates the button click from within your code.
Btn_Search_Click(Btn_Search, EventArgs.Empty);
}
or
Btn_Search_Click(null, EventArgs.Empty);
or for your function
Btn_Search_Function(null, EventArgs.Empty)
I want to call the event from within another event.
I want to call this event
private void gv_client_CellContentClick(object sender, DataGridViewCellEventArgs e){}
From this event as
private void update_staff_Click(object sender, EventArgs e){
//some codes
gv_client_CellContentClick(); // i want to call this event here
}
If the event is in same class you can call it like
private void update_staff_Click(object sender, EventArgs e){
//some codes
gv_client_CellContentClick(sender,e); // i want to call this event here
}
As per our comment thread, it seems you want to call the method (as opposed to raising the event).
In your original handler, you can simply call the method:
private void update_staff_Click(object sender, EventArgs e)
{
var rowIndex = ???;
var columnIndex = ???;
var args = new DataGridViewCellEventArgs(columnIndex, rowIndex);
gv_client_CellContentClick(sender, args); // Note: You might need to change sender too if you know this function uses it...
}
The bit you'll need to figure out is the row/column indexes. Presumably this can be retrieved based on the location of the "update_staff" button/control being clicked - tip: cast "sender" to whatever control type you know it is to work out which button/control was clicked.
I need to send a click event to refreshToolStripMenuItem from another form. Here is what I have, for some reason it doesn't work. Help please.
Menu item click:
public void refreshToolStripMenuItem_Click(object sender, EventArgs e)
{
noteslist.Items.Clear();
idlist.Items.Clear();
setnotes();
}
Code used to send event:
frmnotes notes = new frmnotes();
notes.refreshToolStripMenuItem_Click(this, e);
this.Close();
Dont call the event itself.
It's bad code.
Put the create an own protected void updateMyList() Method.
internal void updateMyList()
{
noteslist.Items.Clear();
idlist.Items.Clear();
setnotes();
}
Then call the update-method from within your event.
private void refreshToolStripMenuItem_Click(object sender, EventArgs e)
{
updateMyList();
}
Then simply call the update-method from your form:
frmnotes notes = new frmnotes();
notes.updateMyList();
this.Close();
Btw.: Set the modifier of your Click events i.e. refreshToolStripMenuItem_Click to private.
You never should call them from outside the form.
Take a look at the MVC pattern for more info. It really helps.
If I have a button which does something and also a double-click event on a data grid which I want to do the same thing, what is the best way to ensure that only one function has to be maintained?
Apart from doing the following, is there any fancy C# way to indicate that two events are to do the same thing?
void button1_Click(...) { MyFunction(); }
void dataGrid1_DoubleClick(...) { MyFunction(); }
void MyFunction() { // do stuff }
I suppose that you are talking about a DataGridView (WinForms) so the signature of the event DoubleClick in the DataGridView and the signature of Click event on a button control is the same.
(An EventHadler). In this case you can simply set the same method using the form designer or manually bind the event
dataGridView1.DoubleClick += new EventHandler(MyFunction);
button1.Click += new EventHandler(MyFunction);
Of course the MyFunction method should match the expected signature of an EventHandler
private void MyFunction(object sender, EventArgs e)
{
// do your work
}
Reviewing my answer after a few minutes I wish to add:
If you find yourself in a situation in which you need to differentiate between the controls using the sender object (like Control c = sender as Control; if (c.Name == "someName") ) I really suggest you to return to the first idea. Call a common method but keep the EventHandler separated for each control involved.
Using VS, in the form's designer view You can set the procedure You want to call to each control's each event in the control's properties window.
image
Just to add to what Steve said, you will want to bind these events to your function manually in the Load event of your form, instead of using the events under the lightning bolt in the properties window in the designer, like so:
private void Form1_Load(object sender, EventArgs e)
{
button1.Click += MyMethod;
dataGridView1.DoubleClick += MyMethod;
}
void MyMethod(object sender, EventArgs e)
{
//Do Stuff
}
Also, declaring a new instance of the EventHandler class has been redundant since Anonymous methods were introduced to C#, you can just point the event directly at the method as shown above.
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