work with two dropdown control...

Hi,

IF your dropdows are static then follow the below code,

protected void DropDownList_SelectedIndexChanged(object sender, EventArgs e)

{

var value = DropDownList1.SelectedValue;

if(value == "1")

{

DropDownList2.SelectedValue="2";

}

else if(value == "2")

{

DropDownList2.SelectedValue="1";

}

Else if your dropdown values are dynamic then follow the below link,

http://www.c-sharpcorner.com/UploadFile/009464/cascading-one-dropdownlist-with-other-dropdownlist-in-asp-ne/

Hope this may helps you. Thanks in advance