Question

I want to create a method in code behind that creates a button and places it in a PlaceHolder. I want this button to have a Click event.

After calling the “test” method button is placed correctly but the click event is not called.

private void test()
    {
        Button linkBtn1 = new Button();
        linkBtn1.Text = "linkBtn1";
        linkBtn1.OnClientClick = "return false;";
        linkBtn1.Click += new EventHandler(linkBtn1_Click);
        PagesPlaceHolder.Controls.Add(linkBtn1);          

    }

    void linkBtn1_Click(object sender, EventArgs e)
    {
        throw new NotImplementedException();
    }

Answer 1

Removing the OnClientClick = "return false;" is necessary but not sufficient to get this to work. If you want the event handler on the dynamically added button to be triggered, you’ll need to add this button every time the page loads.

One simple way would be to save the fact that the button has been added in ViewState, and then check that on PageLoad, and re-add the button if needed.

Here’s a sample that works for me (and throws the exception when clicked)

protected void Page_Load(object sender, EventArgs e)
{
    //if the button was added previously, add it again
    if (ViewState["Added"] != null && (bool)ViewState["Added"])
        addButton();
}

//this is the method that adds the button
protected void add_Click(object sender, EventArgs e) {
    ViewState["Added"] = true;
    addButton();
}

private void addButton() {
    Button linkBtn1 = new Button();
    linkBtn1.Text = "linkBtn1";
    linkBtn1.Click += new EventHandler(linkBtn1_Click);
    placeholder1.Controls.Add(linkBtn1);
}

void linkBtn1_Click(object sender, EventArgs e) {
    throw new Exception("Button Click Event Triggered.  Hello yellow screen!!!");
}