Button Click in a TableCell never fires and table disappears

Question

In my ASP.NET Webforms app, I have a `table` in which I add all data dynamically. One row contains `Buttons` in each cell. I want the button to fire `onclick` event when the user clicks on it. But, with the below code, the event never fires and the table disappears. Here's the code :

        <asp:Table ID="floorTable" runat="server"  Width="100%" GridLines="Both">

        </asp:Table>

In Code behind :

       // This method is called on a DropDownList SelectedItemChanged Event - so

       // the buttons cannot be created in Page_Load or so. Have to create 

       // totally based on the DropDown selected item.

        private void PopulateFloorRow(int floorNo, FloorPattern fp)

        {

            int cols = fp.UnitPattern.Count;

            // HEADER ROW

            TableRow thead = new TableRow(); 

            thead.Width = Unit.Percentage(100);

            thead.TableSection = TableRowSection.TableHeader;

            TableCell theadCell = new TableCell();

            theadCell.ColumnSpan = cols;

            Label title = new Label();

            title.Text = "Floor # " + floorNo;

            theadCell.Controls.Add(title);

            thead.Controls.Add(theadCell);

            TableRow planRow = GetFloorPlan(floorNo, fp);

            TableRow tr = new TableRow();

            TableCell tc = null;

            int tcWidPerc = (int)fp.UnitPattern.Count / 100;

            foreach (UnitPattern up in fp.UnitPattern)

            {                

                tc = new TableCell();

                Button imgBtn = new Button();

                                

                // On Adding BELOW Line - ERROR - 0x800a1391 - JavaScript runtime error: 'UnitLinkClicked' is undefined

                //imgBtn.Attributes.Add("onClick", "UnitLinkClicked(this)");

                imgBtn.CommandArgument = up.UnitPatternId.ToString(); // I want to know which button is pressed. So, sort of Tag

                imgBtn.Click += new EventHandler(UnitLinkClicked);

                imgBtn.BorderWidth = Unit.Pixel(10);

                imgBtn.BorderColor = Color.Transparent;

                imgBtn.Width = Unit.Percentage(100);

                if (up.UnitNo != null)

                {

                    imgBtn.Text = up.UnitNo;

                }

                tc.Controls.Add(imgBtn);

                tr.Controls.Add(tc);

            }

            floorTable.Rows.Add(thead);

            floorTable.Rows.Add(planRow);

            floorTable.Rows.Add(tr);

            // Create Footer

            PopulateTableFooter(cols);

        }

        protected void UnitLinkClicked(object sender, EventArgs e)

        {

            Button btn = (Button)(sender);

            string upId = btn.CommandArgument;

            System.Diagnostics.Debug.WriteLine("LINK Button clicked Of UP ID :" + upId);

        }

In CODE OF SELECTEDiNDEXCHANGED ADDED
My DropDown_SelectedIndexChanged Code :

        protected void floorDropDownList_SelectedIndexChanged(object sender, EventArgs e)

        {

            if (selectedProject == null)

                selectedProject = _db.Projects.Find(projectsList.SelectedValue);

            System.Diagnostics.Debug.WriteLine("SELCTED Project = " + selectedProject.ProjectId);

            // "Select Floor" is selected, so Hide floor Table

            if (floorDropDownList.SelectedValue == "-1")

            {

                floorTable.Visible = false;

            }

            else

            {

                int floorNo = int.Parse(floorDropDownList.SelectedValue);

                if (floorNo > 0)

                {

                    PopulateFloorRow(floorNo, (FloorPattern)selectedProject.FloorPattern.ElementAt(floorNo - 1));

                }

            }

        }

If If I had selected "3" in my drop down, the table appears as expected. I click on a button and the table disappears, but the value in the drop down in still "3" only.

With the above code, I when I click on a button, the `UnitLinkClicked` event is never fired (I had added breakpoint) and the whole table disappears.

Can you say what problem can this be ? A button by default is meant to be `AutoPostBack` & it doesn't have that property too. What am I missing here and how to solve this. Am stuck on this since days and trying to figure out.

Any help is highly appreciated.

Thanks.