C# 如果为空，如何使反序列化返回null
我正在进行反序列化，现在我能够按预期成功地反序列化XML 然而，当我试图反序列化一个不存在的XML标记时，我得到了C# 如果为空，如何使反序列化返回null,c#,xml,C#,Xml,我正在进行反序列化，现在我能够按预期成功地反序列化XML 然而，当我试图反序列化一个不存在的XML标记时，我得到了NullException错误，这是可以理解的 如果标记不存在，我希望它只返回null，而不是获取错误消息，但我不确定如何执行该操作 List<FolkbokforingspostTYPE> deserializedList = new List<FolkbokforingspostTYPE>(); deserializedList = Deserialize
NullExceptionnullList<FolkbokforingspostTYPE> deserializedList = new List<FolkbokforingspostTYPE>();
deserializedList = Deserialize<List<FolkbokforingspostTYPE>>();
var PostNr = deserializedList.Select(item => item.Personpost.Adresser.Folkbokforingsadress.PostNr).ToList();
class Program
{
static void Main(string[] args)
{
//try
//{
List<FolkbokforingspostTYPE> deserializedList = new List<FolkbokforingspostTYPE>();
deserializedList = Deserialize<List<FolkbokforingspostTYPE>>();
var PersonalIdentityNumber = deserializedList.Select(item => item.Personpost.PersonId.PersonNr).ToList();
var FirstName = deserializedList.Select(item => item.Personpost.Namn.Fornamn).ToList();
var LastName = deserializedList.Select(item => item.Personpost.Namn.Efternamn).ToList();
var LanKod = deserializedList.Select(item => item.Personpost.Folkbokforing.LanKod).ToList();
var Kommunkod = deserializedList.Select(item => item.Personpost.Folkbokforing.KommunKod).ToList();
var UtdelAdress2 = deserializedList.Select(item => item.Personpost.Adresser.Folkbokforingsadress.Utdelningsadress2).ToList();
var PostNr = deserializedList.Select(item => item?.Personpost?.Adresser?.Folkbokforingsadress?.PostNr).ToList();
//var PostOrt = deserializedList.Select(item => item.Personpost.Adresser.Folkbokforingsadress.Postort).ToList();
//var FodelselanKod = deserializedList.Select(item => item.Personpost.Fodelse.HemortSverige.FodelselanKod).ToList();
//var Fodelseforsamling = deserializedList.Select(item => item.Personpost.Fodelse.HemortSverige.Fodelseforsamling).ToList();
var MedborgarskapslandKod = deserializedList.Select(item => item.Personpost.Medborgarskap.MedborgarskapslandKod).ToList();
var Medborgarskapsdatum = deserializedList.Select(item => item.Personpost.Medborgarskap.Medborgarskapsdatum).ToList();
//var zipped = PersonalIdentityNumber.Zip(FirstName, Tuple.Create);
// foreach (var tuple in zipped)
// {
// //Console.WriteLine(tuple.Item1);
// //Console.WriteLine(tuple.Item2);
// }
//Console.WriteLine(PersonalIdentityNumber.Count());
//for (int i = 0; i < PersonalIdentityNumber.Count; i++)
//{
// var personnummer = PersonalIdentityNumber[i];
// var fornamn = FirstName[i];
// var efternamn = LastName[i];
// var lankod = LanKod[i];
// var kommunkod = Kommunkod[i];
// var utdelAdress2 = UtdelAdress2[i];
// var postNr = PostNr[i];
// var postOrt = PostOrt[i];
// var fodelselanKod = FodelselanKod[i];
// var fodelseforsamling = Fodelseforsamling[i];
// var medborgarskapslandKod = MedborgarskapslandKod[i];
// var medborgarskapsdatum = Medborgarskapsdatum[i];
// use your variables
//}
//Console.WriteLine(PersonalIdentityNumber.Count());
//foreach (var i in PersonalIdentityNumber)
//{
// Console.WriteLine("Personnummer: " + i);
// foreach(var a in FirstName)
// {
// Console.WriteLine("Namn: " + a);
// }
string connetionString = null;
SqlDataAdapter adpter = new SqlDataAdapter();
DataSet ds = new DataSet();
XmlReader xmlFile;
connetionString = "Data Source=tsrv2062;Initial Catalog=Bums;User ID=BumsUser;Password=2tusen7Bums";
xmlFile = XmlReader.Create("navetout.xml", new XmlReaderSettings());
ds.ReadXml(xmlFile);
using (var connection = new SqlConnection(connetionString))
{
connection.Open();
DateTime datum = DateTime.Now;
SqlCommand command1 = new SqlCommand("UPDATE Seamen SET FirstName = @FirstName, LastName = @LastName, NationalRegistrationCountyCode = @NationalRegistrationCountyCode, NationalRegistrationMunicipalityCode = @NationalRegistrationMunicipalityCode, CitizenshipCode = @CitizenshipCode, LastChangedDate = @LastChangedDate WHERE PersonalIdentityNumber = @PersonalIdentityNumber", connection);
for (int i = 0; i < PersonalIdentityNumber.Count; i++)
{
var personnummer = PersonalIdentityNumber[i];
var fornamn = FirstName[i];
var efternamn = LastName[i];
var lankod = LanKod[i];
var kommunkod = Kommunkod[i];
var utdelAdress2 = UtdelAdress2[i];
var postNr = PostNr[i];
//var postOrt = PostOrt[i];
//var fodelselanKod = FodelselanKod[i];
//var fodelseforsamling = Fodelseforsamling[i];
var medborgarskapslandKod = MedborgarskapslandKod[i];
// var medborgarskapsdatum = Medborgarskapsdatum[i];
command1.Parameters.Clear();
command1.Parameters.AddWithValue("@PersonalIdentityNumber", personnummer);
command1.Parameters.AddWithValue("@FirstName", fornamn);
command1.Parameters.AddWithValue("@LastName", efternamn);
command1.Parameters.AddWithValue("@NationalRegistrationCountyCode", lankod);
command1.Parameters.AddWithValue("@NationalRegistrationMunicipalityCode", kommunkod);
command1.Parameters.AddWithValue("@NationalRegistrationDistributionAddress2", utdelAdress2);
//command1.Parameters.AddWithValue("@NationalRegistrationPostCode", postNr);
//command1.Parameters.AddWithValue("@NationalRegistrationCity", postOrt);
//command1.Parameters.AddWithValue("@BirthCountyCode", fodelselanKod);
//command1.Parameters.AddWithValue("@BirthParish", fodelseforsamling);
command1.Parameters.AddWithValue("@CitizenshipCode", medborgarskapslandKod);
// command1.Parameters.AddWithValue("@CitizenshipDate", medborgarskapsdatum);
command1.Parameters.AddWithValue("@LastChangedDate", datum);
command1.ExecuteNonQuery();
Console.WriteLine(personnummer);
}
}
Console.WriteLine("Done");
}
//}// Put a break-point here, then mouse-over PersonalIdentityNumber... deserializedList contains everything if you need it
// catch (Exception)
// {
// throw;
// }
// Console.ReadKey();
//}
private static T Deserialize<T>() where T : new()
{
// Create an instance of T
T ReturnListOfT = CreateInstance<T>();
// Create a new file stream for reading the XML file
using (FileStream ReadFileStream = new FileStream("navetout.xml", FileMode.Open, FileAccess.Read, FileShare.Read))
{
// Construct a XmlSerializer and use it
// to serialize the data from the stream.
XmlSerializer SerializerObj = new XmlSerializer(typeof(T));
try
{
// Deserialize the hashtable from the file
ReturnListOfT = (T)SerializerObj.Deserialize(ReadFileStream);
}
catch (Exception ex)
{
Console.WriteLine(string.Format("Failed to serialize. Reason: {0}", ex.Message));
}
}
// return the Deserialized data.
return ReturnListOfT;
}
// function to create instance of T
public static T CreateInstance<T>() where T : new()
{
return (T)Activator.CreateInstance(typeof(T));
}
类程序
{
静态void Main（字符串[]参数）
{
//试一试
//{
List deserializedList=新列表（）；
反序列化列表=反序列化（）；
var PersonalIdentityNumber=deserializedList.Select（item=>item.Personpost.PersonId.PersonNr.ToList（）；
var FirstName=deserializedList.Select（item=>item.Personpost.Namn.Fornamn.ToList（）；
var LastName=deserializedList.Select（item=>item.Personpost.Namn.Efternamn.ToList（）；
var LanKod=deserializedList.Select（item=>item.Personpost.Folkbokforing.LanKod.ToList（）；
var Kommunkod=deserializedList.Select（item=>item.Personpost.Folkbokforing.Kommunkod.ToList（）；
var UtdelAdress2=deserializedList.Select（item=>item.Personpost.Adresser.folkbokforingsaddress.Utdelningsadress2.ToList（）；
var PostNr=反序列化列表。选择（项=>项？.Personpost？.Adresser？.FolkBookForingsAdress？.PostNr）。ToList（）；
//var posort=deserializedList.Select（item=>item.Personpost.Adresser.folkbokforingsaddress.posort）.ToList（）；
//var FodelselanKod=deserializedList.Select（item=>item.Personpost.Fodelse.HemortSverige.FodelselanKod.ToList（）；
//var Fodelseforsamling=deserializedList.Select（item=>item.Personpost.Fodelse.HemortSverige.Fodelseforsamling.ToList（）；
var MedborgarskapslandKod=deserializedList.Select（item=>item.Personpost.Medborgarskap.MedborgarskapslandKod.ToList（）；
var medborgarskapsdatam=deserializedList.Select（item=>item.Personpost.Medborgarskap.medborgarskapsdatam.ToList（）；
//var zipped=PersonalIdentityNumber.Zip（FirstName，Tuple.Create）；
//foreach（压缩的变量元组）
// {
////Console.WriteLine（tuple.Item1）；
////Console.WriteLine（tuple.Item2）；
// }
//Console.WriteLine（PersonalIdentityNumber.Count（））；
//对于（int i=0；i class Program
{
static void Main(string[] args)
{
//try
//{
List<FolkbokforingspostTYPE> deserializedList = new List<FolkbokforingspostTYPE>();
deserializedList = Deserialize<List<FolkbokforingspostTYPE>>();
var PersonalIdentityNumber = deserializedList.Select(item => item.Personpost.PersonId.PersonNr).ToList();
var FirstName = deserializedList.Select(item => item.Personpost.Namn.Fornamn).ToList();
var LastName = deserializedList.Select(item => item.Personpost.Namn.Efternamn).ToList();
var LanKod = deserializedList.Select(item => item.Personpost.Folkbokforing.LanKod).ToList();
var Kommunkod = deserializedList.Select(item => item.Personpost.Folkbokforing.KommunKod).ToList();
var UtdelAdress2 = deserializedList.Select(item => item.Personpost.Adresser.Folkbokforingsadress.Utdelningsadress2).ToList();
var PostNr = deserializedList.Select(item => item?.Personpost?.Adresser?.Folkbokforingsadress?.PostNr).ToList();
//var PostOrt = deserializedList.Select(item => item.Personpost.Adresser.Folkbokforingsadress.Postort).ToList();
//var FodelselanKod = deserializedList.Select(item => item.Personpost.Fodelse.HemortSverige.FodelselanKod).ToList();
//var Fodelseforsamling = deserializedList.Select(item => item.Personpost.Fodelse.HemortSverige.Fodelseforsamling).ToList();
var MedborgarskapslandKod = deserializedList.Select(item => item.Personpost.Medborgarskap.MedborgarskapslandKod).ToList();
var Medborgarskapsdatum = deserializedList.Select(item => item.Personpost.Medborgarskap.Medborgarskapsdatum).ToList();
//var zipped = PersonalIdentityNumber.Zip(FirstName, Tuple.Create);
// foreach (var tuple in zipped)
// {
// //Console.WriteLine(tuple.Item1);
// //Console.WriteLine(tuple.Item2);
// }
//Console.WriteLine(PersonalIdentityNumber.Count());
//for (int i = 0; i < PersonalIdentityNumber.Count; i++)
//{
// var personnummer = PersonalIdentityNumber[i];
// var fornamn = FirstName[i];
// var efternamn = LastName[i];
// var lankod = LanKod[i];
// var kommunkod = Kommunkod[i];
// var utdelAdress2 = UtdelAdress2[i];
// var postNr = PostNr[i];
// var postOrt = PostOrt[i];
// var fodelselanKod = FodelselanKod[i];
// var fodelseforsamling = Fodelseforsamling[i];
// var medborgarskapslandKod = MedborgarskapslandKod[i];
// var medborgarskapsdatum = Medborgarskapsdatum[i];
// use your variables
//}
//Console.WriteLine(PersonalIdentityNumber.Count());
//foreach (var i in PersonalIdentityNumber)
//{
// Console.WriteLine("Personnummer: " + i);
// foreach(var a in FirstName)
// {
// Console.WriteLine("Namn: " + a);
// }
string connetionString = null;
SqlDataAdapter adpter = new SqlDataAdapter();
DataSet ds = new DataSet();
XmlReader xmlFile;
connetionString = "Data Source=tsrv2062;Initial Catalog=Bums;User ID=BumsUser;Password=2tusen7Bums";
xmlFile = XmlReader.Create("navetout.xml", new XmlReaderSettings());
ds.ReadXml(xmlFile);
using (var connection = new SqlConnection(connetionString))
{
connection.Open();
DateTime datum = DateTime.Now;
SqlCommand command1 = new SqlCommand("UPDATE Seamen SET FirstName = @FirstName, LastName = @LastName, NationalRegistrationCountyCode = @NationalRegistrationCountyCode, NationalRegistrationMunicipalityCode = @NationalRegistrationMunicipalityCode, CitizenshipCode = @CitizenshipCode, LastChangedDate = @LastChangedDate WHERE PersonalIdentityNumber = @PersonalIdentityNumber", connection);
for (int i = 0; i < PersonalIdentityNumber.Count; i++)
{
var personnummer = PersonalIdentityNumber[i];
var fornamn = FirstName[i];
var efternamn = LastName[i];
var lankod = LanKod[i];
var kommunkod = Kommunkod[i];
var utdelAdress2 = UtdelAdress2[i];
var postNr = PostNr[i];
//var postOrt = PostOrt[i];
//var fodelselanKod = FodelselanKod[i];
//var fodelseforsamling = Fodelseforsamling[i];
var medborgarskapslandKod = MedborgarskapslandKod[i];
// var medborgarskapsdatum = Medborgarskapsdatum[i];
command1.Parameters.Clear();
command1.Parameters.AddWithValue("@PersonalIdentityNumber", personnummer);
command1.Parameters.AddWithValue("@FirstName", fornamn);
command1.Parameters.AddWithValue("@LastName", efternamn);
command1.Parameters.AddWithValue("@NationalRegistrationCountyCode", lankod);
command1.Parameters.AddWithValue("@NationalRegistrationMunicipalityCode", kommunkod);
command1.Parameters.AddWithValue("@NationalRegistrationDistributionAddress2", utdelAdress2);
//command1.Parameters.AddWithValue("@NationalRegistrationPostCode", postNr);
//command1.Parameters.AddWithValue("@NationalRegistrationCity", postOrt);
//command1.Parameters.AddWithValue("@BirthCountyCode", fodelselanKod);
//command1.Parameters.AddWithValue("@BirthParish", fodelseforsamling);
command1.Parameters.AddWithValue("@CitizenshipCode", medborgarskapslandKod);
// command1.Parameters.AddWithValue("@CitizenshipDate", medborgarskapsdatum);
command1.Parameters.AddWithValue("@LastChangedDate", datum);
command1.ExecuteNonQuery();
Console.WriteLine(personnummer);
}
}
Console.WriteLine("Done");
}
//}// Put a break-point here, then mouse-over PersonalIdentityNumber... deserializedList contains everything if you need it
// catch (Exception)
// {
// throw;
// }
// Console.ReadKey();
//}
private static T Deserialize<T>() where T : new()
{
// Create an instance of T
T ReturnListOfT = CreateInstance<T>();
// Create a new file stream for reading the XML file
using (FileStream ReadFileStream = new FileStream("navetout.xml", FileMode.Open, FileAccess.Read, FileShare.Read))
{
// Construct a XmlSerializer and use it
// to serialize the data from the stream.
XmlSerializer SerializerObj = new XmlSerializer(typeof(T));
try
{
// Deserialize the hashtable from the file
ReturnListOfT = (T)SerializerObj.Deserialize(ReadFileStream);
}
catch (Exception ex)
{
Console.WriteLine(string.Format("Failed to serialize. Reason: {0}", ex.Message));
}
}
// return the Deserialized data.
return ReturnListOfT;
}
// function to create instance of T
public static T CreateInstance<T>() where T : new()
{
return (T)Activator.CreateInstance(typeof(T));
}
var PostNr =
deserializedList
.Select(item => item.Personpost.Adresser.Folkbokforingsadress?.PostNr)
.ToList();
var PostNr = deserializedList.Select(item => item?.Personpost?.Adresser?.Folkbokforingsadress?.PostNr).ToList();
var result = x?.Y
var PostNr = deserializedList.Where(item => item.Personpost.Adresser.Folkbokforingsadress != null).Select(item2 => item2.Personpost.Adresser.Folkbokforingsadress.PostNr).ToList();