在ASP.NET中动态创建下拉菜单

Question

I have a table with 3 columns

  EmployeeId EmployeeName ReportingTo 1 A 2 B 1 3 C 1 4 D 1 5 E 2 6 F 3 7 I 3 8 J 4 9 K 8 

Employee Ids are unique. ReportingTo is id of person to whom employee is reporting. ReportingTo is null means A is Boss.

In Asp.net, I want to create a page with one dropdownlist by default. In that dropdownlist EmployeeId whose reportingto is null will be loaded. when I select that dropdown with EmployeeId 1 then next dropdownlist will get created & fill with employees who are reporting to EmployeeId 1.

I have created this whole page, but for that i am generating dropdownlist manually in aspx page.

Anyone can guide me how to create this scenario with dynamic dropdownlist, so I can generate any number of dropdowns & fill it dynamically.

Answer 1

You can add a placeholder control on your web page and then create the new dropdown and add it to the placeholder like so:

private void AddDropDown(){
  var dl = new DropDownList();
  dl.ID="empDDL";
  dl.DataSource = list;
  dl.DataBind();
  myPlaceholer.Controls.Add(dl);
}

Hope this helps.

Answer 2

You use ASP.Net cascade dropdownlist. This example

http://www.aspsnippets.com/Articles/Creating-Cascading-DropDownLists-in-ASP.Net.aspx