Question

protected void ddlEnvironment_SelectedIndexChanged(object sender, EventArgs e)
{
    if (ddlEnvironment.SelectedIndex == 0)
    {
        ddlServers.Items.Add("item1");
    }

    if (ddlEnvironment.SelectedIndex == 1)
    {
        ddlServers.Items.Add("item2");
    }

    if (ddlEnvironment.Text == "Production")
    {
    }
}

The above is not working. When I make a selection on ddlEnvironment and it is the first item on the list (index 0), the other dropdownlist is not upading with “item1”. Why?

Answer 1

There could be different reasons by default dropdown list do no do postback.

• Check if you have AutoPostBack="true"

• You bind the ddlEnvironment in !Page.IsPostBack block so that it maintains its state on postback

  if(!Page.IsPostBack)
  {
     ddlEnvironment.AuutoPostBack = true;
     ddlEnvironment.DataSource = datasource; 
     ddlEnvironment.DataBind();
  }