Question

I have three dropdowns, which are all loaded in the same function. How do I grey out dropdown 2 & 3? I want them to activate if a certain choice is made on dropdown 1.

Answer 1

If you’re using the AJAX ControlKit you can use cascading dropdowns:

http://www.asp.net/ajaxLibrary/AjaxControlToolkitSampleSite/CascadingDropDown/CascadingDropDown.aspx

If not you can add an event handler for each drop box OnSelectedIndexChanged, then perfom your logic on postback. (set textbox 1 & 2 do .Enable = false onLoad)

if(Textbox1.Text == "hello world"){
Textbox2.enabled = true;
}

Or you can use javascript to do it clientside like this: so disable the postback for the dropdown, use the OnClient javascript hooks and implement enable/disable in javascript.

function checkDrop(DropDown)
{
  ...check logic disable Dropdown etc
  document.getElementById(DropDown).disabled = true;
}