Question

In Ajaxcontroltoolkit website they do a lot of async upates in their labels

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

In this website, if you select Audi -> S4 -> Metallic, the Label below this DropDowns is updated automatically (before: [No response provided yet] after: You have chosen a Azure Audi A4. Nice car!)

can anyone share a simple example of how to do this?

Answer 1

from the ajaxcontrol toolkit sample project:

protected void DropDownList3_SelectedIndexChanged(object sender, EventArgs e)
{
    // Get selected values
    string make = DropDownList1.SelectedItem.Text;
    string model = DropDownList2.SelectedItem.Text;
    string color = DropDownList3.SelectedItem.Text;

    // Output result string based on which values are specified
    if (string.IsNullOrEmpty(make))
    {
        Label1.Text = "Please select a make.";
    }
    else if (string.IsNullOrEmpty(model))
    {
        Label1.Text = "Please select a model.";
    }
    else if (string.IsNullOrEmpty(color))
    {
        Label1.Text = "Please select a color.";
    }
    else
    {
        Label1.Text = string.Format("You have chosen a {0} {1} {2}. Nice car!", color, make, model);
    }
}