Synchronize Data in Secondary User Control(s) Based Upon User Selections

This code shows how to create two DropDownList controls where selecting an item in the first list populates the items in the second list।

public partial class _Default : System.Web.UI.Page

{

protected void Page_Load(object sender, EventArgs e)

{

if (!Page.IsPostBack)

{

DropDownList1.Items.Add(new ListItem("Select Country", "0"));

DropDownList1.Items.Add(new ListItem("Egypt", "1"));

DropDownList1.Items.Add(new ListItem("Saudi Arabia", "2"));

DropDownList2.Enabled = false;

}

}

public void GetGovernora(string index)

{

DropDownList2.Enabled = true;

switch (index)

{

case "1":

DropDownList2.Items.Clear();

DropDownList2.Items.Add(new ListItem("Cairo","1"));

DropDownList2.Items.Add(new ListItem("Alex","2"));

DropDownList2.Items.Add(new ListItem("Mansoura","3"));

DropDownList2.Items.Add(new ListItem("Domiatta","4"));

break;

case "2":

DropDownList2.Items.Clear();

DropDownList2.Items.Add(new ListItem("Ryiad","1"));

DropDownList2.Items.Add(new ListItem("Gada", "2"));

DropDownList2.Items.Add(new ListItem("Jezan", "3"));

break;

default:

DropDownList2.Items.Clear();

DropDownList2.Items.Add("No Avaliable Country");

DropDownList2.Enabled = false;

break;

}

}

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)

{

GetGovernora(DropDownList1.SelectedValue);

}

}