Develop Reference

restrict a setter to a static list of values

I have the following models
public class CustomEvent
{
private string _tag;
public int Id { get; set; }
public int PId { get; set; }
public DateTimeOffset TimeStamp { get; set; }
public string Mentor { get; set; }
public string Type { get; set; }
public string Tag
{
get => _tag;
set
{
_tag = GetTagTypeList.GetTagType(typeof(TagType)).Contains(value) ? value : "Unspecified";
}
}
}
public static class TagType
{
public const string Unspecified = "Unspecified";
public const string AmxPersonalItemCreate = "Amx.PersonalItem.Create";
public const string AmxPersonalItemUpdate = "Amx.PersonalItem.Update";
public const string AmxPersonalItemDelete = "Amx.PersonalItem.Delete";
public const string AmxRegionCreate = "Amx.Region.Create";
public const string AmxRegionUpdate = "Amx.Region.Delete";
public const string AmxRegionDelete = "Amx.Region.Update";
}
public class GetTagTypeList
{
public static List<String> GetTagType(Type type)
{
return type.GetFields(BindingFlags.Public | BindingFlags.Static | BindingFlags.FlattenHierarchy)
.Select(x=>x.GetValue(null).ToString()).ToList();
}
}
The above code restricts the setter to the list of static values. However this is very inefficient, as it is reflecting over the class every single time the method [GetTagType] is called.
I now have a requirement to Create a TagType class with a private constructor, and static values.
Given the values to be expressed have "." in them, it will require a custom json serializer as well.
I have read somewhere that a solution could be to use nested classes to get values which match the string being created.
i.e. for "Amx.PersonalItem.Create" we could create a class which resemble:
public static class Amx
{
public static class PersonalItem
{
public static TagType Create { get; } = new TagType("Amx.PersonalItem.Create");
}
}
I need to integrate the above example into my CustomEvent Class.
Or any other solution that uses static values to achieve same result.
Would appreciate any help ?

How about making a static item in the class that builds the list and stores it in a static variable? That means you can build the list once no matter how many times your setter is called. You still have to search the list but you don't need to use reflection.

Add class properties from the List and put them into the string together with a comma as a delimiter

Although the thing I want to do seems be really trivial I can not find a way to achieve what I want. I know there exist multiple questions how to put class properties into the list together and separate it by a comma like that on SO, but none of them seemed to be relevant to my case.
I have a class Form defined as follows:
public class Form
{
public string CustomerName { get; set; }
public string CustomerAdress { get; set; }
public string CustomerNumber { get; set; }
public string OfficeAdress { get; set; }
public string Date { get; set; }
public Boolean FunctionalTest { get; set; }
public string Signature { get; set; }
public Form()
{
}
}
In the MainPage.xaml.cs, I create a List<Form> with the Form class properties and subsequently I would like to create a string with all of those class properties separated by a comma. For that case I use basic Join method with Select which converts any kinds of objects to string.
I do that by createCSV method inside MainPage.xaml.cs :
void createCSV()
{
var records = new List<Form>
{
new Form {CustomerName = customerName.Text,
CustomerAdress = customerAdress.Text,
CustomerNumber = customerNumber.Text,
OfficeAdress = officeAdress.Text,
Date = date.Date.ToString("MM/dd/yyyy"),
FunctionalTest = testPicker.ToString()=="YES" ? true : false,
Signature = signature.Text
}
};
string results = String.Join(",", (object)records.Select(o => o.ToString()));
}
The problem is instead of the desirable outcome which is:"Mark Brown,123 High Level Street,01578454521,43 Falmouth Road,12/15/2020,false,Brown"
I am getting: "System.Linq.Enumerable+SelectListIterator'2[MyApp.Form,System.String]"
PS. As you have noticed I am newbie in C#. Instead of non constructive criticism of the code, please for a valuable reply which would help me to understand what am I doing wrong.
Thanks in advance

In the Form class, You can override the ToString() method and use System.Reflection to get your comma string.
Form.cs
public class Form
{
public string CustomerName { get; set; }
public string CustomerAdress { get; set; }
public string CustomerNumber { get; set; }
public string OfficeAdress { get; set; }
public string Date { get; set; }
public bool FunctionalTest { get; set; }
public string Signature { get; set; }
public override string ToString()
{
string modelString = string.Empty;
PropertyInfo[] properties = typeof(Form).GetProperties();
foreach (PropertyInfo property in properties)
{
var value = property.GetValue(this); // you should add a null check here before doing value.ToString as it will break on null
modelString += value.ToString() + ",";
}
return modelString;
}
}
Code
List<string> CSVDataList = new List<string>();
List<Form> FormList = new List<Form>();
...
foreach (var data in FormList)
{
CSVDataList.Add(data.ToString());
}
Now you have a list of string CSVDataList with each Form object's data in comma style
P.S.
for DateTime
var value = property.GetValue(this);
if(value is DateTime date)
{
modelString += date.ToString("dd.MM.yyyy") + ",";
}

Dynamic method return type in C#

I need your help. I've got the following situation that I have a method with has to determine some conditions and depending on these conditions, returning an object of a specific type.
Now, I do not want to say public object methodXY() with object as return type but I have the approach which does not seem to work yet.
public T methodXY<T>()
{
if (condition A)
return (T)Convert.ChangeType(myValue, typeof(myType));
else if (condition B)
return (T)Convert.ChangeType(myValue, typeof(myOtherType));
else
throw new exception("xyz")
}
But with this, it seems that I have to set the return type already when calling the method. That's what I don't want and don't can.
//myType looks like this
public class myType
{
public string name;
public string firstname;
public string address;
}
and
//myOtherType looks like
public class myOtherType
{
public string name;
public string firstname;
}
Do you need more or more detailed information? Let me know.
Thanks in advance :-)
EDIT:
Here is the complete code sample of the method with object
public object myMethod(MyDto myDto)
{
userHasRoles = GetUserRoles();
if (userHasRoles .Contains("Admin"))
return (mapper.Map<myType>(myDto));
else if (userHasRoles.Contains("User"))
return (mapper.Map<myOtherType>(myDto));
throw new Exception("No elements!");
}

As far as I understand the problem, you need to return a more complete data when the retriever is the admin, and a not-so-complete one when not.
If that is the objective, then you can retrieve the appropriate data from the database and fill in an object of one of the following classes:
public class PersonData {
public string Name { get; private set; }
public string Surname { get; private set; }
}
public class ExtendedPersonData: PersonData {
public string Name { get; private set; }
public string Surname { get; private set; }
public string Address { get; private set; }
}
Since the latter class inherits from the former, you can just create a List<PersonData> and that will cover both cases.
Another, different approach: the data class takes into account the user in order to return or not certain data:
class Person {
public Person(User usr, string address)
{
this.User = usr;
this.address = address;
}
public string User { get; private set; }
public string Name { get; private set; }
public string Surname { get; private set; }
public string Address {
get {
string toret = "N/A";
if ( this.User.IsAdmin() ) {
toret = this.address;
}
return toret;
}
}
private string address;
}
Neither of both solutions is perfect, and both have their own issues, but the problem, at least how you stated it, cannot be solved.
Hope this helps.

Assigning data to attributes and static attributes directly in c#

I have a method as follows which gets data and stores them to specific variables. I also have two static variables that preserves their value if a condition is met. My question is how can I store this data in attributes in a specific class ?
Like for example, I have a class called UserDetails with attributes :
UserDetails class
public class UserDetails {
public static string RateCountry { get; set; }
public static string RateWeek { get; set; }
public int Start { get; set; }
public int Length { get; set; }
public string Name { get; set; }
public string Address { get; set; }
}
Second Class
For now, its working like this. But I want to enhance it by making use of objects.
public static string RateCountry { get; private set; }
public static string RateWeek { get; private set; }
public ActionResult ShowList()
{
int start = Convert.ToInt32(Request["start"]);
int length = Convert.ToInt32(Request["length"]);
string name = Request["search[value]"];
string address = Request[("columns[3][search][value]")];
string rateType = Request[("columns[7][search][value]")];
if (string.IsNullOrEmpty(rateType)) // if null, reset the static variables to null
{
RateCountry = "";
RateWeek = "";
}
else
{
if (CheckDate(rateType)) // if contains date, assign to RateWeek
{
RateWeek = rateType;
}
else
{
RateCountry = rateType; // else if contains a string word, assing to ratecountry
}
}
var items = AssignDetails(start, length, name, address, RateWeek, RateCountry);
return items;
}
Then instead of passing several parameters like start, length, name etc. in the method AssignDetails, I can pass an object of the UserDetails class directly taking into consideration the static variables.
Can someone please help ?

Note: In C#, they are called properties not attributes. Attributes are a totally different thing.
What you want to do is straight forward:
Firstly, you need to change your method so it accepts your class UserDetails as an argument:
public void AssignDetails(UserDetails userDetails)
{
// Use userDetails here to do whatever you want
}
Secondly, when you call the above method, you need to pass the argument to it. You can create an instance of UserDetails and pass it to the AssignDetails method:
var userDetails = new UserDetails
{
Start = start,
Length = length,
Name = name
Address = address
}
I am not sure why RateWeek, and RateCountry properties are static in your class, but to set those you can do them as below (Please note it is using the class and not the instance of the class):
UserDetails.RateWeek = RateWeek;

You could make use of the instance's properties as an indirection to the class' static properties, although all this thing is really ugly in terms of design.
public class UserDetails
{
public static string PersistedRateCountry { get; set; }
public static string PersistedRateWeek { get; set; }
public static string RateCountry
{
get { return string.IsNullOrEmpty(rateType) ? "" : PersistedRateCountry; }
set { PersistedRateCountry = value; }
}
public static string RateWeek
{
get { return string.IsNullOrEmpty(rateType) ? "" : PersistedRateWeek; }
set { PersistedRateWeek= value; }
}
public static string RateWeek { get; set; }
public int Start { get; set; }
public int Length { get; set; }
public string Name { get; set; }
public string Address { get; set; }
}
I strongly suggest you to move these static properties out to another class, which would be responsible for persisting them.
E.g. try to separate your Data Object (which just holds data) from your Business Object (which contains business logic, and is constructed by receiving a Data Object as parameter). Put all that crazy persistence logic in the Business Object, and use the Business Object everywhere in your code (instead of using the Data Object).
Keep your classes short and clean. If you are coding a lot in the same class, it's probably because you got a bad object-oriented design.

How to apply different regular expression to view model property?

I have the following view model in asp.net mvc app.
[Required]
public string Name { get; set; }
[Required]
public int Age { get; set; }
public DateTime DateOfBirth { get; set; }
public Address CurrentAddress { get; set; }
My Address object contains Post Code property, that has RegularExpession attribute to validate UK post codes.
public class Address
{
...
[RegularExpression(#"^[A-Z]{1,2}[0-9][0-9A-Z]? [0-9][A-Z]{2}$")]
public string PostCode { get; set; }
...
}
I want to expand the current functionality to validate PostCode using different regular expression when for example person is non-Uk resident.
Any ideas how I could achieve that? Is there any way to modify regular expression value at run-time?
If you need more information, please let me know and I'll update the question.

You can create your own Person dependand attribute:
public class MyTestAttribute : ValidationAttribute
{
private readonly Regex _regex1;
private readonly Regex _regex2;
public MyTestAttribute(string regex1, string regex2)
{
_regex1 = new Regex(regex1);
_regex2 = new Regex(regex2);
}
public override bool Match(object obj)
{
var input = (string) obj;
if (IsUk())
{
return _regex1.IsMatch(input);
}
return _regex2.IsMatch(input);
}
private bool IsUk()
{
//is person in UK
}
}