通用事件处理程序未从动态按钮触发

Question

I have a bunch of buttons being dynamically created and setting its click event to an event handler...When I run it they handler in never firing, I've stepped through the code and nothing seems out of the ordinary but it just won't fire.

Here is a snippet of the code where the button is being created..

for (cellCtr = 1; cellCtr <= 9; cellCtr++)
            {

                Button button = new Button();

                HyperLink link = new HyperLink();

                TableCell tCell = new TableCell();

                if (rowCtr == rN)
                    break;

                string myStr = daccess.dsSubjects.Tables[0].Rows[rowCtr]["SubjectName"].ToString();
                int myID = Convert.ToInt32(daccess.dsSubjects.Tables[0].Rows[rowCtr]["SubjectID"].ToString());

                button.ID = Convert.ToString(myID);
                button.Text = myStr;

                button.CssClass = "btn btn-primary btn-sm"; 

                button.Click += ButtonSubjectClick;

                tCell.Controls.Add(button);

                tRow.Cells.Add(tCell);
                rowCtr++;

                if (cellCtr == rN)
                {
                    rowCtr = rowCtr - 1;
                    break;
                }
            }

and here is the handler that's it suppose to call...

void ButtonSubjectClick(object sender, EventArgs e)
    {
        Button button = (Button)sender;
        daccess.DeleteSubjects(Int32.Parse(button.ID.ToString()));
        button.CssClass = "btn-active";  
    }

When its ran, the source looks like this

<input type="submit" name="38" value="Math" id="38" class="btn btn-primary btn-sm" />

Answer 1

This code works for me:

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        // do something if needed
    }

    // outside of postback, you need to add it each time
    Button button = new Button();
    button.ID = "btn1";
    button.Text = "clicky me";
    button.Click += new EventHandler(ButtonSubjectClick);
    pnl.Controls.Add(button);
}

void ButtonSubjectClick(object sender, EventArgs e)
{
    Button button = (Button)sender;
    button.Text = "clicked me";
}

I believe it's a question about how are you adding your button to the page. I'm adding my button at each postback and it is thus registered by the server.

If you are adding your buttons in another event then you could use viewstate or session variables, store some kind of a flag to create the button and then check for this flag in each postback.

Edit, for the sake of clarity, pnl is a Panel on my page:

<form id="form1" runat="server">
<div>
    <asp:Panel ID="pnl" runat="server"></asp:Panel>
</div>
</form>