为什么我的按钮的点击事件没有触发？

Question

I have two Buttons on my Sharepoint 2010 Web Page. One fires (server-side), the other doesn't*. They are set up similarly. Here is the one that does fire:

Button btnSave = new Button();
btnSave.Text = "Save";
btnSave.Click += new EventHandler(btnSave_Click);
this.Controls.Add(btnSave);
. . .
private void btnSave_Click(object sender, EventArgs e)
{
    LiteralControl message = null; // this breakpoint is hit, sho' nuff
. . . // code elided for brevity
}

...and here is the one that isn't invoked:

Button btnGeneratePDF = null;
. . .
btnGeneratePDF = new Button();
btnGeneratePDF.Text = "Generate PDF";
btnGeneratePDF.UseSubmitBehavior = true; // trying this after it didn't work without it... (still doesn't work)
btnGeneratePDF.Click += new EventHandler(btnGenPDF_Click);
this.Controls.Add(btnGeneratePDF);

private void btnGenPDF_Click(object sender, EventArgs e)
{
        GeneratePDF(listOfListItems); // breakpoint here never reached
}        

Why is btnSave's handler invoked when I click it, but btnGeneratePDF's handler is not?

• I can get buttons to fire client-side (jQuery) by using HtmlButtons, but I need this one to fire server-side/C#.

UPDATE

Would the fact that I'm creating the pdfgen button inside the click handler of the other Button have anything to do with this? Here's the significant part of that:

private void btnSave_Click(object sender, EventArgs e)
{
    try
    {
        . . . relatively insignificant code elided for brevity
        Button btnGeneratePDF = new Button();
        btnGeneratePDF.Text = "Generate PDF";
        btnGeneratePDF.UseSubmitBehavior = true; // trying this after it didn't 
    work without it...still doesn't work; don't know why - configuration of this 
    button is the same as for btnSave
        btnGeneratePDF.Click += new EventHandler(btnGenPDF_Click);
        this.Controls.Add(btnGeneratePDF);
        . . . relatively insignificant code elided for brevity

?

UPDATE 2

Only the first (btnSave) button (and not the identically-created btnGeneratePDF button) is marked as type="submit":

<input type="submit" name="ctl00$ctl24$g_5f3fedca_19f7_4bc3_b84e_efbef0c48a33$ctl00$ctl152" value="Save" onclick="javascript:WebForm_DoPostBackWithOptions(new WebForm_PostBackOptions(&quot;ctl00$ctl24$g_5f3fedca_19f7_4bc3_b84e_efbef0c48a33$ctl00$ctl152&quot;, &quot;&quot;, true, &quot;&quot;, &quot;&quot;, false, false))" />

I believe only one button of type submit is allowed, but I tried to shove btnSave out of the way when I was done with it by setting its Enabled property to false, but that did nothing (good).

Answer 1

If you assign the click event handler of the "pdf" button inside the click event of the Save button means that the PDF button is dynamically created and its click event assigned each time you press click on the save button. Only at that time the pdf will get its event assigned.

Answer 2

You must recreate the dynamic control in page processing. Here is an example of how to do it:

protected void Page_Load(object sender, EventArgs e)
    {
        Button b = new Button();
        b.ID = "one";
        b.Text = "one";
        b.Click += B_Click;
        this.form1.Controls.Add(b);

        // this is where the dynamic control is created if id is in postback
        if (Request["two"] != null)
        {
            Button x = new Button();
            x.ID = "two";
            x.Text = "two";
            x.Click += X_Click;
            this.form1.Controls.Add(x);
        }
    }

    private void B_Click(object sender, EventArgs e)
    {
        Button x = new Button();
        x.ID = "two";
        x.Text = "two";
        x.Click += X_Click;
        this.form1.Controls.Add(x);
        LabelOutput.Text += " ...one";

    }

    private void X_Click(object sender, EventArgs e)
    {
        LabelOutput.Text += " ...two";
    }

Answer 3

This is how I got it to work:

0) Declare button at the top:

Button btnGeneratePDF = null;

1) Create and configure it within the Page_Load() event (as suggested by Michael Palermo)

btnGeneratePDF = new Button();
btnGeneratePDF.Text = "Generate PDF";
btnGeneratePDF.UseSubmitBehavior = true; // I don't know if this is necessary
btnGeneratePDF.Click += new EventHandler(btnGenPDF_Click);
btnGeneratePDF.Visible = false;
this.Controls.Add(btnGeneratePDF);

Note that visible is set to false at first

2) Make the "Generate PDF" button visible within the "btnSave" click handler:

btnGeneratePDF.Visible = true;

That's it - it works fine now.