I am creating one button on a page dynamically. Now I want to use the button click event on that button.
How can I do this in C# ASP.NET?
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6 Answers
Button button = new Button();
button.Click += (s,e) => { your code; };
//button.Click += new EventHandler(button_Click);
container.Controls.Add(button);
//protected void button_Click (object sender, EventArgs e) { }
7 Comments
Egor4eg
You have to create button in OnInit method, otherwise event handler won't work
AB Vyas
First of all thnx IN this u write button.Click += (s,e) => { your code; }; s= object sender and e = event argument ri8? but then also button click event not fire ... can u explain me that how it can work..
abatishchev
@amitvyas: This is shorter, but more complex version of the same code. Instead of explicit event handler declaration - implicit using lambda expression and anonymous method:
{ this is anon method with 2 arguments declared }
Sam
This also didn't work for me; the event handler never fired. It might be because a new event handler is created for the button each time a request is received.
nativegrip
dynamic generated event must be register in Page_Load/Page_Init event outside of !IsPostBack.
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The easier one for newbies:
Button button = new Button();
button.Click += new EventHandler(button_Click);
protected void button_Click (object sender, EventArgs e)
{
Button button = sender as Button;
// identify which button was clicked and perform necessary actions
}
4 Comments
Mike
What is the non-newbie version?
A9S6
@MichaelMello: Non-newbie one could have been the lambda one. "button.click += (sender, e) => { // do something here }" :)
Simply add the eventhandler to the button when creating it.
button.Click += new EventHandler(this.button_Click);
void button_Click(object sender, System.EventArgs e)
{
//your stuff...
}
Comments
It is much easier to do:
Button button = new Button();
button.Click += delegate
{
// Your code
};
Comments
You can create button in a simple way, such as:
Button button = new Button();
button.Click += new EventHandler(button_Click);
protected void button_Click (object sender, EventArgs e)
{
Button button = sender as Button;
// identify which button was clicked and perform necessary actions
}
But event probably will not fire, because the element/elements must be recreated at every postback or you will lose the event handler.
I tried this solution that verify that ViewState is already Generated and recreate elements at every postback,
for example, imagine you create your button on an event click:
protected void Button_Click(object sender, EventArgs e)
{
if (Convert.ToString(ViewState["Generated"]) != "true")
{
CreateDynamicElements();
}
}
on postback, for example on page load, you should do this:
protected void Page_Load(object sender, EventArgs e)
{
if (Convert.ToString(ViewState["Generated"]) == "true") {
CreateDynamicElements();
}
}
In CreateDynamicElements() you can put all the elements you need, such as your button.
This worked very well for me.
public void CreateDynamicElements(){
Button button = new Button();
button.Click += new EventHandler(button_Click);
}
Comments
Let's say you have 25 objects and want one process to handle any one objects click event. You could write 25 delegates or use a loop to handle the click event.
public form1()
{
foreach (Panel pl in Container.Components)
{
pl.Click += Panel_Click;
}
}
private void Panel_Click(object sender, EventArgs e)
{
// Process the panel clicks here
int index = Panels.FindIndex(a => a == sender);
...
}
