C# 为什么我在调用一个web服务时遇到这个错误，即序列化类型的对象时检测到循环引用？

我正在aspx页面中使用ASMXWebService。我正在调用它，但它抛出了这个错误

序列化SAPWebServices.clsFunctionalLocation类型的对象时检测到循环引用。

我以前使用过web服务，但这一次真的让我很为难。有什么问题？为什么会这样

单击事件：

protected void btnAdd_Click(object sender, EventArgs e)
    {
        SAPWebServicesSoapClient c = new SAPWebServicesSoapClient("SAPWebServicesSoap");

        List<clsFunctionalLocation> ListFuncLocations = new List<clsFunctionalLocation>();
        SAPWebServices.clsFunctionalLocation objFunLocation = new SAPWebServices.clsFunctionalLocation();

        for(int i=1; i<=Convert.ToInt32(txtBoxRecords.Text); i++)
        {



            objFunLocation.Description = txtDes.Text;
            objFunLocation.EquipmentCategory = txtEqCat.Text;
            objFunLocation.EquipmentNo = txtEqNo.Text + txtBoxRecords.Text;
            objFunLocation.EquipmentType = txtEqNo.Text + txtBoxRecords.Text;
            objFunLocation.FunctionalLocation = txtFL.Text;

            ListFuncLocations.Add(objFunLocation);



        }

        objFunLocation.ListFunctionalLocations = ListFuncLocations.ToArray();

        c.SendFunctionalLocations(objFunLocation);
    }

达尔：

命名空间SAPServicesCollection
{
公共类clsFunctionalLocation
{
公共字符串说明{get；set；}
公共字符串函数分配{get；set；}
公共字符串设备no{get；set；}
公共字符串设备类别{get；set；}
公共字符串设备类型{get；set；}
公共列表ListFunctionalLocations{get；set；}
公共clsFunctionalLocation（）
{
}
公共CLSFunctionAllocResponse InsertFunctionalLocationsSAP（clsFunctionalLocation参数_ObjFunctionalLocations）
{
尝试
{
string query=“InsertFunctionalLocationsSAP”；
string ConnectionString=System.Configuration.ConfigurationManager.ConnectionString[“SAPConnection”].ConnectionString；
CLSFunctionAllocResponse OBJFunctionAllocResponse=新的CLSFunctionAllocResponse（）；
ObjFunctionalLocsResponse.StatusRet=“”；
使用（SqlConnection cn=newsqlconnection（ConnectionString））
使用（SqlCommand cmd=newsqlcommand（query，cn））
{
cmd.CommandType=CommandType.storedProcess；
如果（ListFunctionalLocations.Count>0）
{
foreach（Param_ObjFunctionalLocations.ListFunctionalLocations中的变量遍历器）
{
cmd.Parameters.Add（“@Description”，SqlDbType.VarChar，1000）.Value=traverser.Description；
cmd.Parameters.Add（“@FunctionalLocation”，SqlDbType.VarChar，20）.Value=traverser.FunctionalLocation；
cmd.Parameters.Add（“@EquipmentNo”，SqlDbType.VarChar，20）。Value=traverser.EquipmentNo；
cmd.Parameters.Add（“@EquipmentCategory”，SqlDbType.VarChar，20）。Value=traverser.EquipmentCategory；
cmd.Parameters.Add（“@EquipmentType”，SqlDbType.VarChar，20）。Value=traverser.EquipmentType；
cmd.Parameters.Add（“@StatusRet”，SqlDbType.VarChar，20）.Direction=ParameterDirection.Output；
cmd.Parameters.Add（“@ErrorRet”，SqlDbType.VarChar，100）.Direction=ParameterDirection.Output；
cn.Open（）；
cmd.ExecuteNonQuery（）；
ObjFunctionalLocsResponse.StatusRet=Convert.ToString（cmd.Parameters[“@StatusRet”].Value）；
ObjFunctionalLocsResponse.ErrorRet=Convert.ToString（cmd.Parameters[“@ErrorRet”].Value）；
cmd.Parameters.Clear（）；
cn.Close（）；
}
}
其他的
{
ObjFunctionalLocsResponse.StatusRet=“失败”；
ObjFunctionalLocsResponse.ErrorRet=“未提供任何数据”；
}
}
返回ObjFunctionalLocsResponse；
}
捕获（例外情况除外）
{
掷骰子；
}
}
}
公共类clsFunctionalLocsResponse
{
公共字符串StatusRet{get；set；}
公共字符串ErrorRet{get；set；}
公共clsFunctionalLocsResponse（）
{
}
}
}

在您的类中

clsFunctionalLocation

您有一个相同类型的列表（

list

），在序列化时无法运行。一般来说，你可以说，如果你能用它来构造一个

struct

，它将被序列化，在你的例子中，它不会，因为你是从对象本身引用它，它被称为“curcular引用”

为了避免这样的错误，您应该只序列化

structs

而不是类，这样您就安全了

以下是我所改变的：

• 因为在循环中不使用递归嵌套，所以我删除了它们
• 修复了命名约定冲突
• 将

  insertfunctionallocationsap

  重命名为相应的名称

  appendfunctionallocationsap

• 简化了

  AppendFunctionalLocationsSAP

  的参数
• 在适当的情况下，将显式类型声明替换为

  var

• 将

  FUNCTIONALLOCATION

  和

  FunctionalLocsResponse

  从类移动到结构
• 使用简化的语句
• 删除无用的尝试捕捉

以下是您的结构的外观

public struct FunctionalLocation
{
   public string Description {get; set;}
   public string FunctionalLocation {get; set;}
   public string EquipmentNo { get; set; }
   public string EquipmentCategory { get; set; }
   public string EquipmentType { get; set; }
}

public struct FunctionalLocsResponse
{
   public string StatusRet {get; set;}
   public string ErrorRet {get; set;}
}

public class FunctionalLocationCollection
{
   public string Description {get; set;}
   public string FunctionalLocation {get; set;}
   public string EquipmentNo { get; set; }
   public string EquipmentCategory { get; set; }
   public string EquipmentType { get; set; }
   public List<FunctionalLocation> ListFunctionalLocations {get; set;}

   public FunctionalLocsResponse AppendFunctionalLocationsSAP(List<FunctionalLocation> locationCollection)
   {
      var query = "InsertFunctionalLocationsSAP";
      var locsResponse = new clsFunctionalLocsResponse();
      locsResponse.StatusRet = "";       
      string ConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings["SAPConnection"].ConnectionString;
      using var cn = new SqlConnection(ConnectionString)
      using var cmd = new SqlCommand(query, cn)
      cmd.CommandType = CommandType.StoredProcedure;
      if (ListFunctionalLocations.Count > 0)
      {
         foreach (var item in locationCollection)
         {
            cmd.Parameters.Add("@Description", SqlDbType.VarChar, 1000).Value = item.Description;
            cmd.Parameters.Add("@FunctionalLocation", SqlDbType.VarChar, 20).Value = item.FunctionalLocation;
            cmd.Parameters.Add("@EquipmentNo", SqlDbType.VarChar, 20).Value = item.EquipmentNo;
            cmd.Parameters.Add("@EquipmentCategory", SqlDbType.VarChar, 20).Value = item.EquipmentCategory;
            cmd.Parameters.Add("@EquipmentType", SqlDbType.VarChar, 20).Value = item.EquipmentType;
            cmd.Parameters.Add("@StatusRet", SqlDbType.VarChar, 20).Direction = ParameterDirection.Output;
            cmd.Parameters.Add("@ErrorRet", SqlDbType.VarChar, 100).Direction = ParameterDirection.Output;
            cn.Open();
            cmd.ExecuteNonQuery();
            locsResponse.StatusRet = Convert.ToString(cmd.Parameters["@StatusRet"].Value);
            locsResponse.ErrorRet = Convert.ToString(cmd.Parameters["@ErrorRet"].Value);
            cmd.Parameters.Clear();
            cn.Close();
         }
      }
      else 
      {
         locsResponse.StatusRet = "Failed";
         locsResponse.ErrorRet = "No data has been provided";
      }      
      return locsResponse;
   }
}

公共结构函数分配
{
公共字符串说明{get；set；}
公共字符串函数分配{get；set；}
公共字符串设备no{get；set；}
公共字符串设备类别{get；set；}
公共字符串设备类型{get；set；}
}
公共结构函数响应
{
公共字符串StatusRet{get；set；}
公共字符串ErrorRet{get；set；}
}
公共类函数分配集合
{
公共字符串说明{get；set；}
公共字符串函数分配{get；set；}
公共字符串设备no{get；set；}
公共字符串设备类别{get；set；}
公共字符串设备类型{get；set；}
公共列表ListFunctionalLocations{get；set；}
public FunctionAllocResponse AppendFunctionalLocationsSAP（列表位置集合）
{
var query=“InsertFunctionalLocationsSAP”；
var locsResponse=新的clsFunctionalLocsResponse（）；
本地响应
namespace SAPServicesCollection 
{
    public class clsFunctionalLocation
    {
        public string Description { get; set; }
        public string FunctionalLocation { get; set; }
        public string EquipmentNo { get; set; }
        public string EquipmentCategory { get; set; }
        public string EquipmentType { get; set; }
        public List<clsFunctionalLocation> ListFunctionalLocations { get; set; }

        public clsFunctionalLocation()
        {


        }

        public clsFunctionalLocsResponse InsertFunctionalLocationsSAP(clsFunctionalLocation Param_ObjFunctionalLocations)
        {

            try
            {
                string query = "InsertFunctionalLocationsSAP";
                string ConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings["SAPConnection"].ConnectionString;

                clsFunctionalLocsResponse ObjFunctionalLocsResponse = new clsFunctionalLocsResponse();
                ObjFunctionalLocsResponse.StatusRet = "";

                using (SqlConnection cn = new SqlConnection(ConnectionString))

                using (SqlCommand cmd = new SqlCommand(query, cn))
                {
                    cmd.CommandType = CommandType.StoredProcedure;
                    if (ListFunctionalLocations.Count > 0)
                    {
                        foreach (var traverser in Param_ObjFunctionalLocations.ListFunctionalLocations)
                        {
                            cmd.Parameters.Add("@Description", SqlDbType.VarChar, 1000).Value = traverser.Description;
                            cmd.Parameters.Add("@FunctionalLocation", SqlDbType.VarChar, 20).Value = traverser.FunctionalLocation;
                            cmd.Parameters.Add("@EquipmentNo", SqlDbType.VarChar, 20).Value = traverser.EquipmentNo;
                            cmd.Parameters.Add("@EquipmentCategory", SqlDbType.VarChar, 20).Value = traverser.EquipmentCategory;
                            cmd.Parameters.Add("@EquipmentType", SqlDbType.VarChar, 20).Value = traverser.EquipmentType;
                            cmd.Parameters.Add("@StatusRet", SqlDbType.VarChar, 20).Direction = ParameterDirection.Output;
                            cmd.Parameters.Add("@ErrorRet", SqlDbType.VarChar, 100).Direction = ParameterDirection.Output;

                            cn.Open();

                            cmd.ExecuteNonQuery();

                            ObjFunctionalLocsResponse.StatusRet = Convert.ToString(cmd.Parameters["@StatusRet"].Value);
                            ObjFunctionalLocsResponse.ErrorRet = Convert.ToString(cmd.Parameters["@ErrorRet"].Value);

                            cmd.Parameters.Clear();

                            cn.Close();
                        }
                    }
                    else 
                    {
                        ObjFunctionalLocsResponse.StatusRet = "Failed";
                        ObjFunctionalLocsResponse.ErrorRet = "No data has been provided";
                    }

                 }

                return ObjFunctionalLocsResponse;
            }
            catch (Exception ex)
            {

                throw ex;
            }
        }
    }

    public class clsFunctionalLocsResponse
    {
        public string StatusRet { get; set; }
        public string ErrorRet { get; set; }

        public clsFunctionalLocsResponse()
        {


        }
    }
}

public struct FunctionalLocation
{
   public string Description {get; set;}
   public string FunctionalLocation {get; set;}
   public string EquipmentNo { get; set; }
   public string EquipmentCategory { get; set; }
   public string EquipmentType { get; set; }
}

public struct FunctionalLocsResponse
{
   public string StatusRet {get; set;}
   public string ErrorRet {get; set;}
}

public class FunctionalLocationCollection
{
   public string Description {get; set;}
   public string FunctionalLocation {get; set;}
   public string EquipmentNo { get; set; }
   public string EquipmentCategory { get; set; }
   public string EquipmentType { get; set; }
   public List<FunctionalLocation> ListFunctionalLocations {get; set;}

   public FunctionalLocsResponse AppendFunctionalLocationsSAP(List<FunctionalLocation> locationCollection)
   {
      var query = "InsertFunctionalLocationsSAP";
      var locsResponse = new clsFunctionalLocsResponse();
      locsResponse.StatusRet = "";       
      string ConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings["SAPConnection"].ConnectionString;
      using var cn = new SqlConnection(ConnectionString)
      using var cmd = new SqlCommand(query, cn)
      cmd.CommandType = CommandType.StoredProcedure;
      if (ListFunctionalLocations.Count > 0)
      {
         foreach (var item in locationCollection)
         {
            cmd.Parameters.Add("@Description", SqlDbType.VarChar, 1000).Value = item.Description;
            cmd.Parameters.Add("@FunctionalLocation", SqlDbType.VarChar, 20).Value = item.FunctionalLocation;
            cmd.Parameters.Add("@EquipmentNo", SqlDbType.VarChar, 20).Value = item.EquipmentNo;
            cmd.Parameters.Add("@EquipmentCategory", SqlDbType.VarChar, 20).Value = item.EquipmentCategory;
            cmd.Parameters.Add("@EquipmentType", SqlDbType.VarChar, 20).Value = item.EquipmentType;
            cmd.Parameters.Add("@StatusRet", SqlDbType.VarChar, 20).Direction = ParameterDirection.Output;
            cmd.Parameters.Add("@ErrorRet", SqlDbType.VarChar, 100).Direction = ParameterDirection.Output;
            cn.Open();
            cmd.ExecuteNonQuery();
            locsResponse.StatusRet = Convert.ToString(cmd.Parameters["@StatusRet"].Value);
            locsResponse.ErrorRet = Convert.ToString(cmd.Parameters["@ErrorRet"].Value);
            cmd.Parameters.Clear();
            cn.Close();
         }
      }
      else 
      {
         locsResponse.StatusRet = "Failed";
         locsResponse.ErrorRet = "No data has been provided";
      }      
      return locsResponse;
   }
}