Drop down list

I wish to made other server control like textbox enabled after selecting the drop down list during run time, can i do it?

protected void ddlGroupType_SelectedIndexChanged(object sender, EventArgs e)
    {
        int groupType;     
        groupType = ddlGroupType.SelectedIndex;

        if (groupType == 1)
        {
            ddlNoStud.Enabled = true;
            tbStud1.Enabled = true;
            tbStud2.Enabled = true;
            tbStud3.Enabled = true;
            tbS ...