ajaxToolkit:CascadingDropDown获得错误

Question

我想使用ajaxtoolkit创建级联下拉列表，但是有错误。

因为新版本的ajaxcontroltoolkit工具箱已经删除了ToolkitScriptManager，所以我使用了脚本管理器。

<ajaxToolkit:CascadingDropDown 
    ID="cdlOffice" 
    TargetControlID="DropDownList1" 
    PromptText="Select Office" 
    PromptValue="" 
    ServicePath="~/WebService1.asmx" 
    ServiceMethod="GetLocation" 
    runat="server" 
    Category="LocationId" 
    LoadingText="Loading..." />

<div class="form-group">
                            <asp:Label runat="server" AssociatedControlID="DropDownList1" CssClass="col-md-2 control-label">Location</asp:Label>
                            <div class="col-md-10">
                                <asp:DropDownList id="DropDownList1" runat="server" class="select2-me" data-placeholder="--SELECT--" data-rule-required="true" style="width:250px;" />
                            </div>
                        </div>

和WebService1.asmx如下所示

  [WebService(Namespace = "http://tempuri.org/")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [System.ComponentModel.ToolboxItem(false)]
    // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. 
    // [System.Web.Script.Services.ScriptService]
    public class WebService1 : System.Web.Services.WebService
    {

        [WebMethod]
        public CascadingDropDownNameValue[] GetLocation(string knownCategoryValues)
        {
            string query = "SELECT DISTINCT ITOFF_NAME, ITOFF_ID FROM ITOFF_TBL ORDER BY ITOFF_NAME";
            List<CascadingDropDownNameValue> Location = GetData(query);
            return Location.ToArray();
        }

        [WebMethod]
        public CascadingDropDownNameValue[] GetFloor(string knownCategoryValues)
        {
            string Location = CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues)["LocationId"];
            string query = string.Format("SELECT ITOFF_LEVEL, ITOFF_ID FROM ITOFF_TBL WHERE ITOFF_NAME = {0}", Location);
            List<CascadingDropDownNameValue> Floor = GetData(query);
            return Floor.ToArray();
        }

        private List<CascadingDropDownNameValue> GetData(string query)
        {
            string conString = ConfigurationManager.ConnectionStrings["ITFORMConnectionString"].ConnectionString;
            SqlCommand cmd = new SqlCommand(query);
            List<CascadingDropDownNameValue> values = new List<CascadingDropDownNameValue>();
            using (SqlConnection con = new SqlConnection(conString))
            {
                con.Open();
                cmd.Connection = con;
                using (SqlDataReader reader = cmd.ExecuteReader())
                {
                    while (reader.Read())
                    {
                        values.Add(new CascadingDropDownNameValue
                        {
                            name = reader[0].ToString(),
                            value = reader[1].ToString()
                        });
                    }
                    reader.Close();
                    con.Close();
                    return values;
                }
            }
        }

    }

我在显示错误

http://localhost:60461/Scripts/WebForms/MsAjax/MicrosoftAjax.js中第97862列第6行的未处理异常 0x800a138f - JavaScript运行时错误:无法获得未定义或空引用的属性“webServiceFailedNoMsg”

我从谷歌上学到的所有代码。有没有遗漏什么或做错了什么？

Answer 1

尝试将字符串Param 'knownCategoryValues‘从您的getLocation() web方法定义中删除：

 [WebMethod]
            public CascadingDropDownNameValue[] GetLocation()
            {
                string query = "SELECT DISTINCT ITOFF_NAME, ITOFF_ID FROM ITOFF_TBL ORDER BY ITOFF_NAME";
                List<CascadingDropDownNameValue> Location = GetData(query);
                return Location.ToArray();
            }

并从级联locationID定义中删除DropDown属性。

或者，如果要从另一个下拉列表中获取locationID，那么将其放在其中并将其定义为ParentControlID。