Develop Reference

How to define a "description" for each XMLElement of a class at design time

I have this class that i want to serialize to a XML file. I want to add a "Description" attribute to each property of the class like below. Is it possible? Or how can i achieve this?
[Serializable]
public class Arm : INotifyPropertyChanged{
private int _ID;
private ArmStore _aStore;
private ArmDimension _dimension;
private Zone _accessibleZone;
[XmlElement("ID")]
[XmlAttribute("description"), Value="It defines ID number of the Arm"]
public int ID {
get { return _ID; }
set { _ID = value; }
}
[XmlElement("Store")]
[XmlAttribute("description"), Value="It defines the Store of the Arm"]
public ArmStore aStore {
get { return _aStore; }
set {
_aStore = value;
Notify("aStore");
}
}
[XmlElement("Dimension")]
[XmlAttribute("description"), Value="It defines the dimension of the Arm"]
public ArmDimension dimension {
get { return _dimension; }
set {
_dimension = value;
Notify("dimension");
}
}
I want to have the following result:
<ID description="It defines ID number of the Arm">1</ID>
<Dimension description="It defines the dimension of the Arm">
<XMin>-150</XMin>
<XMax>150</XMax>
<YMin>-300</YMin>
<YMax>300</YMax>
</Dimension>
Thanks in advance!

You can create custom attribute
[AttributeUsage(AttributeTargets.Property)]
public class XmlDescription : Attribute
{
public string Value { get; set; }
}
and set it on the desired properties
public class Arm
{
[XmlElement("ID")]
[XmlDescription(Value = "It defines ID number of the Arm")]
public int ID { get; set; }
[XmlElement("Store")]
[XmlDescription(Value = "It defines the Store of the Arm")]
public ArmStore Store { get; set; }
[XmlElement("Dimension")]
[XmlDescription(Value = "It defines the dimension of the Arm")]
public ArmDimension Dimension { get; set; }
}
Next, you need to create a custom XmlWriter
public class DescriptionWriter : XmlTextWriter
{
public DescriptionWriter(string filename, Encoding encoding) : base(filename, encoding) { }
public override void WriteStartElement(string prefix, string localName, string ns)
{
base.WriteStartElement(prefix, localName, ns);
var prop = typeof(Arm).GetProperty(localName);
if (prop != null)
{
var data = prop.GetCustomAttributesData();
var description = data.FirstOrDefault(a => a.AttributeType == typeof(XmlDescription));
if (description != null)
{
var value = description.NamedArguments.First().TypedValue.ToString().Trim('"');
base.WriteAttributeString("description", value);
}
}
}
}
There are many shortcomings in this implementation. In particular, the property name and XmlElement name must be the same. Or it won't work getting the property by name: GetProperty(localName).
Use it as follows
Arm arm = ...
var xs = new XmlSerializer(typeof(Arm));
using (var writer = new DescriptionWriter("test.xml", Encoding.Unicode))
{
writer.Formatting = Formatting.Indented;
xs.Serialize(writer, arm);
}

Try following :
[XmlRoot("Arm")]
public class Arm
{
[XmlElement("ID")]
public ID id {get;set;}
[XmlElement("Dimension")]
public Dimension dimension { get; set;}
}
[XmlRoot("Dimension")]
public class Dimension
{
[XmlAttribute("description")]
public string Value { get; set; }
[XmlElement("XMin")]
public int XMin { get; set; }
[XmlElement("XMax")]
public int XMax { get; set; }
[XmlElement("YMin")]
public int YMin { get; set; }
[XmlElement("YMax")]
public int YMax { get; set; }
}
[XmlElement("ID")]
public class ID
{
[XmlAttribute("description")]
public string Value { get; set; }
[XmlText]
public int value { get; set; }
}

Error when deserializing xml into array

I'm trying to deserialize xml retrieved from a web service call
using (var client = new WebClient())
{
client.UseDefaultCredentials = true;
var content = client.DownloadString("call to service");
System.Xml.Serialization.XmlSerializer serializer = new System.Xml.Serialization.XmlSerializer(typeof(List<NewCourseApply.Models.Education>));
using (TextReader textReader = new StringReader(content))
{
var e = (List<NewCourseApply.Models.Education>)serializer.Deserialize(textReader);
}
}
The xml returned from the service is:
<ArrayOfEducation xmlns="http://schemas.datacontract.org/2004/07/CovUni.Domain.Admissions" xmlns:i="http://www.w3.org/2001/XMLSchema-instance"><Education><_auditList xmlns="http://schemas.datacontract.org/2004/07/CovUni.Common.Base" xmlns:a="http://schemas.microsoft.com/2003/10/Serialization/Arrays"/><_apCode>670104552</_apCode><_attendanceType>FT</_attendanceType><_educationId>1</_educationId><_establishmentDetails>test school</_establishmentDetails><_fromDate>2016-11-01T00:00:00</_fromDate><_toDate>2016-11-22T00:00:00</_toDate><_ucasSchoolCode/></Education></ArrayOfEducation>
My client side object is:
[Serializable]
public class Education
{
protected int _apCode;
protected int _educationId;
protected string _establishmentDetails;
protected string _ucasSchoolCode;
protected DateTime? _fromDate;
protected DateTime? _toDate;
protected string _attendanceType;
protected string _auditList;
public int ApCode
{ get { return _apCode;}
set { _apCode = value;} }
public int EducationId
{ get { return _educationId;}
set { _educationId = value;} }
public string EstablishmentDetails
{ get { return _establishmentDetails;}
set { _establishmentDetails = value;} }
public string UcasSchoolCode
{ get { return _ucasSchoolCode;}
set { _ucasSchoolCode = value;} }
public DateTime? FromDate
{ get { return _fromDate;}
set { _fromDate = value;} }
public DateTime? ToDate
{ get { return _toDate;}
set { _toDate = value;} }
public string AttendanceType
{ get { return _attendanceType;}
set { _attendanceType = value;} }
public string AuditList
{ get { return _auditList;}
set { _auditList = value;} }
}
The error I am getting is:
There is an error in XML document (1, 2).
<ArrayOfEducation xmlns='http://schemas.datacontract.org/2004/07/CovUni.Domain.Admissions'> was not expected.
Also if I call a web service call and get the singular Education response i.e.:
<Education xmlns="http://schemas.datacontract.org/2004/07/CovUni.Domain.Admissions" xmlns:i="http://www.w3.org/2001/XMLSchema-instance"><_auditList xmlns="http://schemas.datacontract.org/2004/07/CovUni.Common.Base" xmlns:a="http://schemas.microsoft.com/2003/10/Serialization/Arrays"/><_apCode>670104552</_apCode><_attendanceType>FT</_attendanceType><_educationId>1</_educationId><_establishmentDetails>test school</_establishmentDetails><_fromDate>2016-11-01T00:00:00</_fromDate><_toDate>2016-11-22T00:00:00</_toDate><_ucasSchoolCode/></Education>
Surely I just need one Simple Education class on the client side that can deserialise from the 2 examples of xml i have provided i.e. array and non array
Can some of you kind souls let me know where i'm going wrong or if there's a better way of doing this?
Many Thanks

Change the Class to
[XmlRoot("ArrayOfEducation", Namespace = "http://schemas.datacontract.org/2004/07/CovUni.Domain.Admissions")]
public class ArrayOfEducation
{
[XmlElement("Education")]
public List<ContainerEducation> education { get; set; }
}
public class ContainerEducation
{
[XmlElement(ElementName = "_apCode")]
public int _apCode { get; set; }
[XmlElement(ElementName = "_educationId")]
public int _educationId { get; set; }
[XmlElement(ElementName = "_establishmentDetails")]
public string _establishmentDetails { get; set; }
[XmlElement(ElementName = "_ucasSchoolCode")]
public string _ucasSchoolCode { get; set; }
[XmlElement(ElementName = "_fromDate")]
public DateTime? _fromDate { get; set; }
[XmlElement(ElementName = "_toDate")]
public DateTime? _toDate { get; set; }
[XmlElement(ElementName = "_attendanceType")]
public string _attendanceType { get; set; }
[XmlElement(ElementName = "_auditList", Namespace = "http://schemas.datacontract.org/2004/07/CovUni.Common.Base")]
public string _auditList { get; set; }
}
And Deserialize below way. Now, when I run the code to deserialize your XML, I do get the objects filled nicely.
XmlSerializer mySerializer = new XmlSerializer(typeof(ArrayOfEducation));
using (TextReader textReader = new StringReader(content))
{
ArrayOfEducation arrEdu = (ArrayOfEducation)mySerializer.Deserialize(textReader);
}
Update as per your comment:
If you are sure that web service is going to send single Education then you need to change the class to
[XmlRoot("ArrayOfEducation", Namespace = "http://schemas.datacontract.org/2004/07/CovUni.Domain.Admissions")]
public class ArrayOfEducation
{
[XmlElement("Education")]
public ContainerEducation education { get; set; }
}

set is throwing StackOverflowException C#

I am trying to get and send a list of this object to a text file. The text file is in the following format.
name,IDnumber,department,value
there are quite a few lines of this so i used a for to read them in.
This is the code for the read and write to the file.
public List<Employee> ReadFile(string fileName) {
StreamReader fileIn = new StreamReader(fileName);
fileIn = File.OpenText(fileName);
List<Employee> list = new List<Employee>();
string[] test;
string name;
string ID;
string dep;
string post;
while (!fileIn.EndOfStream || !File.Exists(fileName)) {
string inString = fileIn.ReadLine();
test = inString.Split('#');
name = test[0];
ID = test[1];
dep = test[2];
post = test[3];
Employee newEmp = new Employee(name, ID, dep, post);
list.Add(newEmp);
}
fileIn.Close();
return list;
}
public void WriteFile(List<Employee> outList, string file) {
StreamWriter writeOut = new StreamWriter(file);
for (int i = 0; i < outList.Count; i++) {
writeOut.WriteLine(outList[i].name + '#' + outList[i].IDnum + '#' + outList[i].department + '#' + outList[i].position);
}
writeOut.close();
}
This is the code for my class. The error is being thrown at the set.
public class Employee {
public string name { get { return name; } set { name = value; } }
public string IDnum { get { return IDnum; } set { IDnum = value; } }
public string department { get { return department; } set { department = value; } }
public string position { get { return position; } set { position = value; } }
public Employee() {
name = string.Empty;
IDnum = string.Empty;
department = string.Empty;
position = string.Empty;
}
public Employee(string newName, string newID) {
name = newName;
IDnum = newID;
department = string.Empty;
position = string.Empty;
}
public Employee(string newName, string newID, string newDep, string
newPost) {
name = newName;
IDnum = newID;
department = newPost;
position = newDep;
}
}
I am not sure if there is some kind of formatting that I am missing for the set function to function as needed. The This is the function i am calling for the in and out of the file. I believe that it is never making it to the out so it is likely how i am importing the data.

It's a really common gotcha... a C# rite of passage!
Let's take a look at a single property (this applies to all of your properties though)...
public string name { get { return name; } set { name = value; } }
so what happens when you try myObj.name = "foo";?
In the set method, you refer back to the very same property name. So it tries to access name, which goes around again (and again, and again, recursively until you StackOverflow).
A backing field with proper naming conventions is the norm here:
private string name;
public string Name{get { return name; } set{ name = value; }}
or even better, if there's no logic involved, an auto-property.
public string Name{ get; set; }

You keep calling IDnum and other properties over and over recursively, until the stack overflows
public string IDnum { get { return IDnum; } set { IDnum = value; } }
When you do something like
IDnum = someValue;
that calls the setter for IDnum, which runs the code in the setter
IDnum = value
Which in turn calls the setter of IDnum, until you run out of stack.
The Fix
In your case, it looks like you can use automatic properties
public string IDnum { get; set; }

You should change
public string name { get { return name; } set { name = value; } }
public string IDnum { get { return IDnum; } set { IDnum = value; } }
public string department { get { return department; } set { department = value; } }
public string position { get { return position; } set { position = value; } }
to
public string name { get; set; }
public string IDnum { get; set; }
public string department { get; set; }
public string position { get; set; }
or introduce backing fields:
private string _name;
public string name { get { return _name; } set { _name = value; } }
See https://msdn.microsoft.com/en-us/library/bb384054.aspx for more info on Auto-Implemented Properties in C#.
Please note, that the commonly used naming of public properties is PascalCasing. Your properties in PascalCasing would look like this:
public string Name { get; set; }
public string IdNum { get; set; }
public string Department { get; set; }
public string Position { get; set; }

Filtering mongodb data

I have the following model:
Base class:
public abstract class Identifiable{
private ObjectId id;
private string name;
protected Identifiable(){
id = ObjectId.GenerateNewId();
}
[BsonId]
public ObjectId Id{
get { return id; }
set { id = value; }
}
[BsonRequired]
public string Name{
get { return name; }
set { name = value; }
}
}
The name is unique.
A channel class
public class Channel : Identifiable{
private DateTime creationDate;
private string url;
private DailyPrograming dailyPrograming;
public DailyPrograming DailyPrograming{
get { return dailyPrograming; }
set { dailyPrograming = value; }
}
public DateTime CreationDate{
get { return creationDate; }
set { creationDate = value; }
}
public string Url{
get { return url; }
set { url = value; }
}
}
Daily programs. The name property is the date stored as ddMMyyyy:
public class DailyPrograming : Identifiable{
public DailyPrograming(){
DailyPrograms = new List<Program>(30);
}
public IList<Program> DailyPrograms { get; set; }
}
The programs:
public class Program : Identifiable{
private DateTime programDate;
private string category;
private string description;
public DateTime ProgramDate{
get { return programDate; }
set { programDate = value; }
}
public string Category{
get { return category; }
set { category = value; }
}
public string Description{
get { return description; }
set { description = value; }
}
}
Now, I want to filter the program of certain channel for specific date using:
public DailyPrograming GetProgramsForDate(string channelId, string prgDate){
ObjectId id = new ObjectId(channelId);
IMongoQuery query = Query.And(Query<Channel>.EQ(c => c.Id, id),
Query<DailyPrograming>.EQ(dp => dp.Name, prgDate));
var result = Database.GetCollection<DailyPrograming>(CollectionName).Find(query).FirstOrDefault();
return result;
}
But it never returns the existing data. How to retrieve the programings of a channel for a date?
-

var builder = Builders<BsonDocument>.Filter;
var filt = builder.Eq("Price", "9.20")
& builder.Eq("ProductName", "WH-208");
var list = await collection.Find(filt).ToListAsync();
We can use & instead of $and. See this post, for another example.

According to your sample I used id = "54c00c65c215161c7ce2a77c" and prgDate = "2212015"
then I changed the query to this:
var collection = database.GetCollection<Channel>("test6");
var id = new ObjectId("54c00c65c215161c7ce2a77c");
var query = Query.And(Query<Channel>.EQ(c => c.Id, id), Query<Channel>.EQ(c => c.DailyPrograming.Name, "2212015"));
var result = collection.Find(query).FirstOrDefault();
this query works fine
Some point:
Your collection type is Chanel not DailyPrograming
When your collection is Chanel you have to use Query<Channel> and query nested DailyPrograming via Query<Channel>.EQ(c => c.DailyPrograming.Name, "2212015")

Stackoverflow error C# with getter and setter

This is the working class:
namespace Lite
{
public class Spec
{
public int ID { get; set; }
public string Name { get; set; }
public string FriendlyName { get; set; }
public int CategoryID { get; set; }
public int Width { get; set; }
public int Height { get; set; }
public string UOM { get; set; }
public int Pagination { get; set; }
public int ColoursFront { get; set; }
public int ColoursBack { get; set; }
public string Material { get; set; }
public int GSM { get; set; }
public string GSMUOM { get; set; }
public bool Seal { get; set; }
public Spec(int ID)
{
using (CrystalCommon.MainContext db = new CrystalCommon.MainContext())
{
var q = (from c in db.tblSpecifications where c.id == ID select c).SingleOrDefault();
if (q != null)
loadByRec(q);
}
}
public Spec(CrystalCommon.tblSpecification Rec)
{
loadByRec(Rec);
}
public void loadByRec(CrystalCommon.tblSpecification Rec)
{
this.ID = Rec.id;
this.Name = Rec.Title;
this.Width = Convert.ToInt32(Rec.FinishedSizeW.Value);
this.Height = Convert.ToInt32(Rec.FinishedSizeL.Value);
this.UOM = Rec.FlatSizeUOM;
this.Pagination = Rec.TxtPagination.Value;
this.ColoursFront = Convert.ToInt32(Rec.TxtColsF.Value);
this.ColoursBack = Convert.ToInt32(Rec.TxtColsB.Value);
this.Material = Rec.TxtMaterial;
this.GSM = Rec.TxtGSM.Value;
this.GSMUOM = Rec.txtGsmUnit;
this.Seal = Rec.TxtSeal.Value == 1;
}
public string displayDimensions()
{
return Width + " x " + Height + " " + UOM;
}
}
}
Then I try and modify the Name getter and setter:
namespace Lite
{
public class Spec
{
public int ID { get; set; }
// User friendly name if available otherwise fall back on spec name
public string Name { get {
if (null != FriendlyName)
return FriendlyName;
else
return Name;
}
set
{
Name = value;
}
}
public string FriendlyName { get; set; }
public int CategoryID { get; set; }
public int Width { get; set; }
public int Height { get; set; }
public string UOM { get; set; }
public int Pagination { get; set; }
public int ColoursFront { get; set; }
public int ColoursBack { get; set; }
public string Material { get; set; }
public int GSM { get; set; }
public string GSMUOM { get; set; }
public bool Seal { get; set; }
public Spec(int ID)
{
using (CrystalCommon.MainContext db = new CrystalCommon.MainContext())
{
var q = (from c in db.tblSpecifications where c.id == ID select c).SingleOrDefault();
if (q != null)
loadByRec(q);
}
}
public Spec(CrystalCommon.tblSpecification Rec)
{
loadByRec(Rec);
}
public void loadByRec(CrystalCommon.tblSpecification Rec)
{
this.ID = Rec.id;
this.Name = Rec.Title;
this.Width = Convert.ToInt32(Rec.FinishedSizeW.Value);
this.Height = Convert.ToInt32(Rec.FinishedSizeL.Value);
this.UOM = Rec.FlatSizeUOM;
this.Pagination = Rec.TxtPagination.Value;
this.ColoursFront = Convert.ToInt32(Rec.TxtColsF.Value);
this.ColoursBack = Convert.ToInt32(Rec.TxtColsB.Value);
this.Material = Rec.TxtMaterial;
this.GSM = Rec.TxtGSM.Value;
this.GSMUOM = Rec.txtGsmUnit;
this.Seal = Rec.TxtSeal.Value == 1;
}
public string displayDimensions()
{
return Width + " x " + Height + " " + UOM;
}
}
}
On my computer this compiles fine, but the server seems to crash when it runs. (First version works fine). My colleague compiled it on his machine and it threw a "Stack overflow error" apparently, but he's not around for me to get specifics on that right now.
Am I applying the getter correctly here?

This is an endless loop:
public string Name { get {
...
set
{
Name = value;
}
}
The setter will call itself repeatedly until you get the Stack overflow exception.
usually you have a backing variable, so it ends up like this
private string name;
public string Name {
get {
if (null != FriendlyName)
return FriendlyName;
else
return name;
}
set {
name = value;
}
}

Your set is referencing the property itself, and your get is referencing the property itself, both of these will cause a potentially endless loop leading to a StackOverflowException (no more stack space to push the current call into). You need to use a backing field:
private string _name;
public string Name
{
get
{
if (null != FriendlyName)
return FriendlyName;
else
return _name;
}
set
{
_name = value;
}
}
It looks as though you tried to turn an auto-property into a manual one. Auto-properties (public string Name { get; set; }) work because the compiler will create the backing field itself.
As a learning exercise, if you step through with the debugger and step into return Name or Name = value you will see first hand the code going back into the property you are already in.

This is much better.
string _name = "";
public string Name
{
get { return FriendlyName ?? _name; }
set { _name = value; }
}

One of your properties gets and sets itself, see:
public string Name
{
get {
if (null != FriendlyName)
return FriendlyName;
else
return Name; //<-- StackOverflow
}
set
{
Name = value; //<-- StackOverflow
}
}

You have a getter for Name, that calls the property Name, which will call the getter for Name, etc. You need a private field to back the property, and you need to access that backing field in your getter instead.

public string Name { get {
if (null != FriendlyName)
return FriendlyName;
else
return Name;
}
set
{
Name = value;
}
}
Name in the get/set refers to the property. You will need to define a backing field and use that.

If FriendlyName is null then the Name getter attempts to get the value from the Name getter - i.e. it loops. This is what causes the stack overflow.

No you should use a backing field. The error is in the else
public string Name { get {
if (null != FriendlyName)
return FriendlyName;
else
return Name;//error, you're calling the property getter again.
}