AjaxControlToolkit AutoCompleteExtender 不显示建议

我在 asp.net 中使用 AutoCompleteExtender 根据令牌（empno）获取名称和名称。这是从数据库中提取的，我可以在 Chrome Dev-tools 的网络选项卡中看到它。但它不会呈现为建议列表。

我对代码的尝试：

<div class="modal-body">                        
                     <div class="form-group">
                        <label for="pToken">Token</label>
                         <asp:TextBox ID="pToken" runat="server" CssClass="form-control" placeholder="Enter Token No" />                           
                         <ajaxcontrol:AutoCompleteExtender runat="server" 
                                    ID="acToken" TargetControlID="pToken" MinimumPrefixLength="3"
                                    EnableCaching="true" FirstRowSelected="false" 
                                    ServiceMethod="getPatients" ServicePath="CheckPatientDetails.aspx"
                                    CompletionSetCount="6" DelimiterCharacters="|"
                                    CompletionListItemCssClass="AutoCompleteExtender_CompletionListItem"
                                    CompletionListHighlightedItemCssClass="AutoCompleteExtender_HighlightedItem"
                                    CompletionListCssClass="AutoCompleteExtender_CompletionList">
                          </ajaxcontrol:AutoCompleteExtender>
                     </div>
                    <div class="form-group">
                        <label for="pName">Name</label>                            
                        <asp:TextBox ID="pName" runat="server" CssClass="form-control" placeholder="Enter patient name" required />
                    </div>
                    <div class="form-group">
                        <label for="pDesig">Designation</label>                            
                        <asp:TextBox ID="pDesig"  runat="server" CssClass="form-control" placeholder="Enter designation" />
                    </div>
                    <div class="form-group">
                        <label for="pType">Type</label>                            
                        <asp:DropDownList ID="pType" runat="server" CssClass="form-control" required>
                            <asp:ListItem Value="E" Selected="True">Employee</asp:ListItem>
                            <asp:ListItem Value="I">In Patient</asp:ListItem>
                            <asp:ListItem Value="O">Out Patient</asp:ListItem>                        
                            <asp:ListItem Value="X">Others</asp:ListItem>                                
                        </asp:DropDownList>                            
                    </div>

相同的后端代码如下：

[WebMethod]
    [System.Web.Script.Services.ScriptMethod()]
    public static List<Patient> getPatients(string prefixText, int count)
    {
        List<Patient> patientList = new List<Patient>();
        OracleConnection con = null;
        OracleDataReader odr = null;

        string query = "select nvl(emp.empid,'') token,DECODE(SHORTNAME,NULL,FIRSTNAME,SHORTNAME)  name,DESIGSHORT desigdesc" +
                        " from employee emp join designation desig  on (emp.desigcode = desig.desigcode and desig.isactive = 'Y') " +
                        " where empid like '%" + prefixText + "%' and emp.EMPSTATUS = 'A' order by empid";
        try
        {
            con = getHRMSConnection();
            con.Open();
            using (con)
            {
                using (OracleCommand cmd = new OracleCommand(query, con))
                {
                    odr = cmd.ExecuteReader();
                    Patient patient = null;
                    while (odr.Read())
                    {
                        patient = new Patient();
                        patient.setToken(Convert.ToString(odr["token"]));
                        patient.setName(Convert.ToString(odr["name"]));
                        patient.setDesignation(Convert.ToString(odr["desigdesc"]));
                        patientList.Add(patient);
                    }

                }
            }
        }
        catch (Exception ex)
        {

        }
        return patientList;
    }