級聯下拉式獲取錯誤不是所有的代碼返回值

Question

我有兩個下拉菜單。我使用的是Cascading dropdown.My First dropdown is returned result on click of selected data from 1st dropdown that is no records for those does not have value。但對於具有相關數據的選定數據，其顯示方法錯誤。有誰可以提出什麼問題？而在sql服務器，我得到的答案值。 DD_Issue是view和tape_master是數據庫中的表。

Webservice： -

using System; using System.Collections.Generic;使用System.Linq的 ; using System.Web; using System.Web.Services; using System.Data; using System.Data.SqlClient; using System.Configuration; using System.Collections.Specialized; using System.Web.Script.Services;使用AjaxControlToolkit的 ; using System.Diagnostics;對於TapeWebService

/// ///概要描述/// /// ///

[WebService的（命名空間= 「http://tempuri.org/」）] [ WebServiceBinding（ConformsTo = WsiProfiles.BasicProfile1_1）]

//若要允許使用ASP.NET AJAX從腳本調用此Web服務，請取消註釋以下行。 [System.Web.Script.Services.ScriptService]

公共類TapeWebService：System.Web.Services.WebService { 的SqlConnection CON =新的SqlConnection（ConfigurationManager.AppSettings [ 「KK」]的ToString（））;

DataSet ds; 
IssueReturn ir; 
SqlCommand cmd; 
SqlDataAdapter sda; 
public TapeWebService() 
{ 

    //Uncomment the following line if using designed components 
    //InitializeComponent(); 
} 
[ScriptMethod] 
[WebMethod] 
public AjaxControlToolkit.CascadingDropDownNameValue[] FillTape(string knownCategoryValues,string category) 
    { 
     try 
     { 
      con.Open(); 
      cmd = new SqlCommand("Select id, t_code from tape_master", con); 
      cmd.ExecuteNonQuery(); 
      sda = new SqlDataAdapter(cmd); 
      ds = new DataSet(); 
      sda.Fill(ds); 
      con.Close(); 
      List<AjaxControlToolkit.CascadingDropDownNameValue> Tape = new List<AjaxControlToolkit.CascadingDropDownNameValue>(); 
      foreach (DataRow dr in ds.Tables[0].Rows) 
      { 
       string TapeID = Convert.ToString(dr["id"].ToString()); 
       string TapeName = dr["t_code"].ToString(); 
       Tape.Add(new AjaxControlToolkit.CascadingDropDownNameValue(TapeName, TapeID)); 
      } 
      return Tape.ToArray(); 
     } 
     catch (Exception e) 
     { 

      string message = e.Message; 
      HttpContext.Current.Response.Write(e.Message); 
     } 
} 
[ScriptMethod] 
[WebMethod] 
public AjaxControlToolkit.CascadingDropDownNameValue[] FillTapeCode(string knownCategoryValues, string category) 
{ 
    try 
    { 
     string TapeID; 
     StringDictionary Tape = AjaxControlToolkit.CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues); 
     TapeID = Convert.ToString(Tape["Tape"]); 
     con.Open(); 
     cmd = new SqlCommand("Select * from DD_Issue where tapetype='" + TapeID + "'", con); 
     cmd.Parameters.AddWithValue("id", TapeID); 
     cmd.ExecuteNonQuery(); 
     sda = new SqlDataAdapter(cmd); 
     ds = new DataSet(); 
     sda.Fill(ds); 
     con.Close(); 
     List<AjaxControlToolkit.CascadingDropDownNameValue> Code = new List<AjaxControlToolkit.CascadingDropDownNameValue>(); 
     foreach (DataRow dr in ds.Tables[0].Rows) 
     { 
      string TapeCodeID = Convert.ToString(dr["id"].ToString()); 
      string TapeCodeName = dr["fill"].ToString(); 
      Code.Add(new AjaxControlToolkit.CascadingDropDownNameValue(TapeCodeName, TapeCodeID)); 
     } 
     return Code.ToArray(); 
    } 
    catch(Exception e) 
    { 
     string message = e.Message; 
     HttpContext.Current.Response.Write(e.Message); 
    } 
} 

.aspx頁面中： -

<asp:DropDownList ID="DdlTapeType" runat="server" Width="140px" 
                     Height="22px"> 
                    </asp:DropDownList> 

                    <ajaxToolkit:CascadingDropDown ID="CascadingDDtape" runat="server" Category="Tape" 
                  TargetControlID="DdlTapeType" LoadingText="[Loading ...]" 
                  PromptText="Please select a Tape" 
               ServicePath="TapeWebService.asmx" ServiceMethod="FillTape"> 

                    </ajaxToolkit:CascadingDropDown> 

                   </td> 
                   <td class="style31"> 
                    &nbsp;<asp:DropDownList ID="DdlTapeCode" runat="server" 
                     Height="22px" 
                     Width="317px" > 
                    </asp:DropDownList> 

                    <ajaxToolkit:CascadingDropDown ID="CascadingDDCode" runat="server" 
                 TargetControlID="DdlTapeCode" LoadingText="[Loading ...]" 
                 PromptText="Please select a Code" EmptyText="No Records" ServicePath="TapeWebService.asmx" 
                 ServiceMethod="FillTapeCode" Category="Code" ParentControlID="DdlTapeType"> 
                    </ajaxToolkit:CascadingDropDown> 

Answer 1

因爲在catch塊沒有return語句您收到此錯誤。您僅在Try {}中給出了返回，還包括返回。

public AjaxControlToolkit.CascadingDropDownNameValue[] FillTape(string knownCategoryValues,string category) 
    { 
List<AjaxControlToolkit.CascadingDropDownNameValue> Tape = new List<AjaxControlToolkit.CascadingDropDownNameValue>(); 
     try 
     { 
      con.Open(); 
      cmd = new SqlCommand("Select id, t_code from tape_master", con); 
      cmd.ExecuteNonQuery(); 
      sda = new SqlDataAdapter(cmd); 
      ds = new DataSet(); 
      sda.Fill(ds); 
      con.Close(); 

      foreach (DataRow dr in ds.Tables[0].Rows) 
      { 
       string TapeID = Convert.ToString(dr["id"].ToString()); 
       string TapeName = dr["t_code"].ToString(); 
       Tape.Add(new AjaxControlToolkit.CascadingDropDownNameValue(TapeName, TapeID)); 
      } 

     } 
     catch (Exception e) 
     { 

      string message = e.Message; 
      HttpContext.Current.Response.Write(e.Message); 
     } 
return Tape.ToArray(); 
} 
[ScriptMethod] 
[WebMethod] 
public AjaxControlToolkit.CascadingDropDownNameValue[] FillTapeCode(string knownCategoryValues, string category) 
{ 
    List<AjaxControlToolkit.CascadingDropDownNameValue> Code = new List<AjaxControlToolkit.CascadingDropDownNameValue>(); 
    try 
    { 
     string TapeID; 
     StringDictionary Tape = AjaxControlToolkit.CascadingDropDown.ParseKnownCategoryValuesString(knownCategoryValues); 
     TapeID = Convert.ToString(Tape["Tape"]); 
     con.Open(); 
     cmd = new SqlCommand("Select * from DD_Issue where tapetype='" + TapeID + "'", con); 
     cmd.Parameters.AddWithValue("id", TapeID); 
     cmd.ExecuteNonQuery(); 
     sda = new SqlDataAdapter(cmd); 
     ds = new DataSet(); 
     sda.Fill(ds); 
     con.Close(); 

     foreach (DataRow dr in ds.Tables[0].Rows) 
     { 
      string TapeCodeID = Convert.ToString(dr["id"].ToString()); 
      string TapeCodeName = dr["fill"].ToString(); 
      Code.Add(new AjaxControlToolkit.CascadingDropDownNameValue(TapeCodeName, TapeCodeID)); 
     } 

    } 
    catch(Exception e) 
    { 
     string message = e.Message; 
     HttpContext.Current.Response.Write(e.Message); 
    } 
return Code.ToArray(); 
} 

感謝 Ashwani