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在我的MVC應用程序中，我正在使用ajax下拉列表和ajax Cascading下拉列表，我想編寫級聯下拉列表的onChange事件，請告訴我該怎麼做。我將如何調用ajax下拉列表的on change事件？
我發佈了我正在使用的視圖頁面以及創建級聯dropdownlist的js文件。請告訴我所有需要進行更改的位置。
的視圖是如下
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Index1</title>
<script src="../../Scripts/MicrosoftAjax.js" type="text/javascript"></script>
<script type="text/javascript" src="../../Scripts/MicrosoftMvcAjax.js"></script>
<script type="text/javascript" src="../../Scripts/CascadingDropDownList.js"></script>
</head>
<body>
<div>
<label for="Makes">Car Make:</label>
<%= Html.DropDownList("Makes")%>
<label for="Makes">Car Model:</label>
<%= Html.CascadingDropDownList("Models", "Makes")%>
<br />
<%=Html.TextBox ("id",ViewData ["id"]) %>
</div>
</body>
</html>
其中正在形成的級聯下拉列表中的JavaScript：
public static class JavaScriptExtensions
{
public static string CascadingDropDownList(this HtmlHelper helper, string name, string associatedDropDownList)
{
var sb = new StringBuilder();
// render select tag
sb.AppendFormat("<select name='{0}' id='{0}'></select>", name);
sb.AppendLine();
// render data array
sb.AppendLine("<script type='text/javascript'>");
var data = (CascadingSelectList)helper.ViewDataContainer.ViewData[name];
var listItems = data.GetListItems();
var colArray = new List<string>();
foreach (var item in listItems)
colArray.Add(String.Format("{{key:'{0}',value:'{1}',text:'{2}'}}", item.Key, item.Value, item.Text));
var jsArray = String.Join(",", colArray.ToArray());
sb.AppendFormat("$get('{0}').allOptions=[{1}];", name, jsArray);
sb.AppendLine();
sb.AppendFormat("$addHandler($get('{0}'), 'change', Function.createCallback(bindDropDownList, $get('{1}')));", associatedDropDownList, name);
sb.AppendLine();
sb.AppendLine("</script>");
return sb.ToString();
}
}
public class CascadingSelectList
{
private IEnumerable _items;
private string _dataKeyField;
private string _dataValueField;
private string _dataTextField;
public CascadingSelectList(IEnumerable items, string dataKeyField, string dataValueField, string dataTextField)
{
_items = items;
_dataKeyField = dataKeyField;
_dataValueField = dataValueField;
_dataTextField = dataTextField;
}
public List<CascadingListItem> GetListItems()
{
var listItems = new List<CascadingListItem>();
foreach (var item in _items)
{
var key = DataBinder.GetPropertyValue(item, _dataKeyField).ToString();
var value = DataBinder.GetPropertyValue(item, _dataValueField).ToString();
var text = DataBinder.GetPropertyValue(item, _dataTextField).ToString();
listItems.Add(new CascadingListItem(key, value, text));
}
return listItems;
}
}
public class CascadingListItem
{
public CascadingListItem(string key, string value, string text)
{
this.Key = key;
this.Value = value;
this.Text = text;
}
public string Key { get; set; }
public string Value { get; set; }
public string Text { get; set; }
}