asp.net两级联动(包含添加和修改)

  <script language="javascript" type="text/javascript">

  //科目数据初始化

  var subcat = new Array();

  subcat[0] = new Array('0', '请选择科目', '0');

  subcat[1] = new Array('x1', '语文', 'x1yw');

  subcat[2] = new Array('x2', '语文', 'x2yw');

  subcat[3] = new Array('x3', '语文', 'x3yw');

  subcat[4] = new Array('x4', '语文', 'x4yw');

  subcat[5] = new Array('x5', '语文', 'x5yw');

  subcat[6] = new Array('x6', '语文', 'x6yw');

  subcat[7] = new Array('c5', '语文', 'c5yw');

  subcat[8] = new Array('c6', '语文', 'c6yw');

  subcat[9] = new Array('c7', '语文', 'c7yw');

  subcat[10] = new Array('g1', '语文', 'g1yw');

  subcat[11] = new Array('g3', '语文', 'g3yw');

  subcat[12] = new Array('g4', '语文', 'g4yw');

  subcat[13] = new Array('x1', '数学', 'x1sx');

  subcat[14] = new Array('x2', '数学', 'x2sx');

  subcat[15] = new Array('x3', '数学', 'x3sx');

  subcat[16] = new Array('x4', '数学', 'x4sx');

  subcat[17] = new Array('x5', '数学', 'x5sx');

  subcat[18] = new Array('x6', '数学', 'x6sx');

  subcat[19] = new Array('c5', '数学', 'c5sx');

  subcat[20] = new Array('c6', '数学', 'c6sx');

  subcat[21] = new Array('c7', '数学', 'c7sx');

  subcat[22] = new Array('g1', '数学', 'g1sx');

  subcat[23] = new Array('g3', '数学', 'g3sx');

  subcat[24] = new Array('g4', '数学', 'g4sx');

  subcat[25] = new Array('x1', '英语', 'x1yy');

  subcat[26] = new Array('x2', '英语', 'x2yy');

  subcat[27] = new Array('x3', '英语', 'x3yy');

  subcat[28] = new Array('x4', '英语', 'x4yy');

  subcat[29] = new Array('x5', '英语', 'x5yy');

  subcat[30] = new Array('x6', '英语', 'x6yy');

  subcat[31] = new Array('c5', '英语', 'c5yy');

  subcat[32] = new Array('c6', '英语', 'c6yy');

  subcat[33] = new Array('c7', '英语', 'c7yy');

  subcat[34] = new Array('g1', '英语', 'g1yy');

  subcat[35] = new Array('g3', '英语', 'g3yy');

  subcat[36] = new Array('g4', '英语', 'g4yy');

  subcat[37] = new Array('c5', '物理', 'c5wl');

  subcat[38] = new Array('c6', '物理', 'c6wl');

  subcat[39] = new Array('c7', '物理', 'c7wl');

  subcat[40] = new Array('g1', '物理', 'g1wl');

  subcat[41] = new Array('g3', '物理', 'g3wl');

  subcat[42] = new Array('g4', '物理', 'g4wl');

  subcat[43] = new Array('c5', '化学', 'c5hx');

  subcat[44] = new Array('c6', '化学', 'c6hx');

  subcat[45] = new Array('c7', '化学', 'c7hx');

  subcat[46] = new Array('g1', '化学', 'g1hx');

  subcat[47] = new Array('g3', '化学', 'g3hx');

  subcat[48] = new Array('g4', '化学', 'g4hx');

  subcat[49] = new Array('c5', '政治', 'c5zz');

  subcat[50] = new Array('c6', '政治', 'c6zz');

  subcat[51] = new Array('c7', '政治', 'c7zz');

  subcat[52] = new Array('g1', '政治', 'g1zz');

  subcat[53] = new Array('g3', '政治', 'g3zz');

  subcat[54] = new Array('g4', '政治', 'g4zz');

  subcat[55] = new Array('c5', '历史', 'c5ls');

  subcat[56] = new Array('c6', '历史', 'c6ls');

  subcat[57] = new Array('c7', '历史', 'c7ls');

  subcat[58] = new Array('g1', '历史', 'g1ls');

  subcat[59] = new Array('g3', '历史', 'g3ls');

  subcat[60] = new Array('g4', '历史', 'g4ls');

  subcat[61] = new Array('c5', '生物', 'c5sw');

  subcat[62] = new Array('c6', '生物', 'c6sw');

  subcat[63] = new Array('c7', '生物', 'c7sw');

  subcat[64] = new Array('g1', '生物', 'g1sw');

  subcat[65] = new Array('g3', '生物', 'g3sw');

  subcat[66] = new Array('g4', '生物', 'g4sw');

  subcat[67] = new Array('c5', '地理', 'c5dl');

  subcat[68] = new Array('c6', '地理', 'c6dl');

  subcat[69] = new Array('c7', '地理', 'c7dl');

  subcat[70] = new Array('g1', '地理', 'g1dl');

  subcat[71] = new Array('g3', '地理', 'g3dl');

  subcat[72] = new Array('g4', '地理', 'g4dl');

  subcat[73] = new Array('x1', '其它', 'x1qt');

  subcat[74] = new Array('x2', '其它', 'x2qt');

  subcat[75] = new Array('x3', '其它', 'x3qt');

  subcat[76] = new Array('x4', '其它', 'x4qt');

  subcat[77] = new Array('x5', '其它', 'x5qt');

  subcat[78] = new Array('x6', '其它', 'x6qt');

  subcat[79] = new Array('c5', '其它', 'c5qt');

  subcat[80] = new Array('c6', '其它', 'c6qt');

  subcat[81] = new Array('c7', '其它', 'c7qt');

  subcat[82] = new Array('g1', '其它', 'g1qt');

  subcat[83] = new Array('g3', '其它', 'g3qt');

  subcat[84] = new Array('g4', '其它', 'g4qt');

  //选择年级

  function ChangeGrade(obj,id)

  {

  var oObj = document.getElementById(id);

  oObj.length = 0;

  for(i=0; i<subcat.length; i++)

  {

  if(subcat[i][0] == obj)

  {

  oObj.options[oObj.length] = new Option(subcat[i][1], subcat[i][2]);

  }

  }

  }

  //修改页面科目数据加载

  function LoadingCourse()

  {

  var SubjectSelect = "<%=SubjectSelect %>";

  var GradeSelect = "<%=GradeSelect %>";

  if(SubjectSelect != "")

  {

  LoadingSubject(GradeSelect, 'Course', SubjectSelect);

  }

  }

  function LoadingSubject(obj,id, sid)

  {

  var slt = document.forms[0].elements["id"];

  var oObj = document.getElementById(id);

  oObj.length = 0;

  oObj.options[0] = new Option('全部科目', '0');

  for(i=0; i<subcat.length; i++)

  {

  if(subcat[i][0] == obj)

  {

  oObj.options[oObj.length] = new Option(subcat[i][1], subcat[i][2]);

  if(subcat[i][2] == sid)

  {

  oObj.options[oObj.length-1].selected = true;

  }

  }

  }

  }

  </script>

  <body onload="LoadingCourse();">

  <select name="Grade" id="Grade" class="input" onchange="ChangeGrade(this.value,'Course')">

  <option value="0">请选择年级</option>

  <option value="x1" <%=GradeSelect == "x1" ? "selected":"" %>>一年级</option>

  <option value="x2" <%=GradeSelect == "x2" ? "selected":"" %>>二年级</option>

  <option value="x3" <%=GradeSelect == "x3" ? "selected":"" %>>三年级</option>

  <option value="x4" <%=GradeSelect == "x4" ? "selected":"" %>>四年级</option>

  <option value="x5" <%=GradeSelect == "x5" ? "selected":"" %>>五年级</option>

  <option value="x6" <%=GradeSelect == "x6" ? "selected":"" %>>六年级</option>

  <option value="c5" <%=GradeSelect == "c5" ? "selected":"" %>>七年级</option>

  <option value="c6" <%=GradeSelect == "c6" ? "selected":"" %>>八年级</option>

  <option value="c7" <%=GradeSelect == "c7" ? "selected":"" %>>九年级</option>

  <option value="g1" <%=GradeSelect == "g1" ? "selected":"" %>>高一</option>

  <option value="g3" <%=GradeSelect == "g3" ? "selected":"" %>>高二</option>

  <option value="g4" <%=GradeSelect == "g4" ? "selected":"" %>>高三</option>

  </select>

  <select name="Course" id="Course" class="input">

  <option value="0">请选择年级</option>

  </select>

  </body>

  //C#代码

  protected void Page_Load(object sender, System.EventArgs e)

  {

  public string GradeSelect = String.Empty;

  public string SubjectSelect = String.Empty;

  if (!(IsPostBack))

  {

  GradeSelect = Request.QueryString["Grade"];

  SubjectSelect = Request.QueryString["Course"];

  }

  }