Question

我有两个下拉列表。我正在使用级联下拉列表。我的第一个下拉列表是从第一个下拉列表中点击所选数据返回结果，它显示没有那些没有值的记录。但对于具有相关数据的选定数据，其显示方法错误。任何人都可以建议这个问题是什么？在sql server中我得到了答案值。 DD_Issue是view，tape_master是数据库中的表。

web服务： -

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

/// /// TapeWebService的摘要描述 /// /// ///

[WebService（Namespace =“http://tempuri.org/”）] [WebServiceBinding（ConformsTo = WsiProfiles.BasicProfile1_1）]

//要允许使用ASP.NET AJAX从脚本调用此Web Service，请取消注释以下行。 [System.Web.Script.Services.ScriptService]

public class TapeWebService：System.Web.Services.WebService { SqlConnection con = new SqlConnection（ConfigurationManager.AppSettings [“kk”]。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页面： -

<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

您收到此错误，因为catch块中没有return语句。您只在Try {}中返回，包括在catch中返回。

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();
}

由于 Ashwani

级联下拉列表获取错误并非所有代码都返回值

1 个答案: