Develop Reference

C# is there any better way to check if more than 2 properties in an object is not null

I am trying to check if more than 2 properties in a object has value and return invalid string if so
Example :
Class Student
{
string Name
string Code
string SNumber
}
Considering above code example , below scenarios can be written
if(studentObj.Name != null && studentObj.Code != null)
return "invalid";
if(studentObj.Name != null && studentObj.SNumber != null)
return "invalid";
if(studentObj.Code != null && studentObj.SNumber != null)
return "invalid";
Is there a way this can be simplified?
Thanks

typeof(Student).GetFields() // use GetProperties() if you have them, and not fields
.Select(field => field.GetValue(studentObj) as string)
.Count(value => !string.IsNullOrEmpty(value))

You could actually count:
class Student
{
public string Name {get; set;}
public string Code {get; set;}
public string SNumber {get; set;}
}
class StudentValidator
{
public string Validate(Student student)
{
int nonZeroCount = 0;
if( student.Name is object ) nonZeroCount++;
// in C# 9: if( student.Name is not null )
if( student.Code is object ) nonZeroCount++;
if( student.SNumber is object ) nonZeroCount++;
return (nonZeroCount > 2)? "invalid" : "valid";
}
}
Mind that you might prefer to check either with
string.IsNullOrEmtpty(string) or
string.IsNullOrWhitespace(string)

Here you can optionally optimize the select statement, but as an example, I offer this option for discussion:
class Program
{
static void Main(string[] args)
{
var students = new List<Student>
{
new Student{Name = "Mary", Code = "1", SNumber = "001" },
new Student{Name = "Sarah", Code = "", SNumber = "002" },
new Student{Name = "", Code = "3", SNumber = "003" },
new Student{Name = "Katherine", Code = "4", SNumber = "004" },
new Student{Name = "Eva", Code = "", SNumber = "" }
};
var listedProperty = from student in students
select new List<string> { student.Name, student.Code, student.SNumber };
listedProperty
.ToList()
.ForEach(l =>
{
var nullPropertyCount = l.Count(i => string.IsNullOrWhiteSpace(i));
if (nullPropertyCount <= 1)
{
Console.WriteLine(string.Join(", ", l.ToArray()));
}
});
Console.ReadLine();
}
}
Output result to the console:

Own class object attribute get overridden

I have created an object with the attributes String, and the other is a List<String>.
I have also created a static List<MyObject> where i add then all my Objects.
Now my Problem is the second attribute is getting overridden.
For example I have 3 Objects:
Object1: "Name"; List with 3 Strings
Object2: "Name2"; List with 2 Strings
Object3: "Name3"; List with 5 Strings
If i add them now to my Object List, it looks like so
Name; List with 5 Strings
Name2; List with 5 Strings
Name3; List with 5 Strings
It override the second attributes to all the other Objects in the List.
Code:
for (int i = 0; i < 100; i++)
{
if (elo.ReadObjMask(i) > 0)
{
var iRet = elo.PrepareObjectEx(0, 0, i);
maskenname = elo.ObjMName();
if (maskenname != "")
{
for (int e = 0; e < 50; e++)
{
string eigenschaft = elo.GetObjAttribName(e);
if (eigenschaft != "" && eigenschaft != "-")
{
eigenschaften.Add(eigenschaft);
}
}
allMasks.Add(maskenname);
}
else
{
// Do nothing
}
EloMask emask = new EloMask(maskenname, eigenschaften);
staticVariables.allMask.Add(emask);
eigenschaften.Clear();
}
}
Here is my object class:
public class EloMask
{
public string name;
public List<String> eigenschaften;
public EloMask(string iname, List<String> ieigenschaften)
{
name = iname;
eigenschaften = ieigenschaften;
}
}

The List<string> always points to the same instance because you are passing a reference to the list, not a copy. As a result, the list is cleared and filled again for each EloMask that you pass that list into.
To fix your issue, create a new list instead:
if (elo.ReadObjMask(i) > 0)
{
var iRet = elo.PrepareObjectEx(0, 0, i);
maskenname = elo.ObjMName();
// create a new list here!!!
var eigenschaften = new List<string>();
if (maskenname != "")
{
for (int e = 0; e < 50; e++)
{
string eigenschaft = elo.GetObjAttribName(e);
if (eigenschaft != "" && eigenschaft != "-")
{
eigenschaften.Add(eigenschaft);
}
}
allMasks.Add(maskenname);
}
EloMask emask = new EloMask(maskenname, eigenschaften);
staticVariables.allMask.Add(emask);
// clearing the list is no longer needed
}

Here is an example how you can do what you want:
public static List<Person> PersonsList = new List<Person>();
public static Random rd = new Random();
static void Main(string[] args)
{
for (int i = 0; i < 5; i++)
{
List<string> tmpAbilities = new List<string>() {((char)rd.Next(255)).ToString(), ((char)rd.Next(255)).ToString() , ((char)rd.Next(255)).ToString() };
Person tmpPerson = new Person("TmpName_"+i,tmpAbilities);
PersonsList.Add(tmpPerson);
}
foreach (var persona in PersonsList)
{
Console.WriteLine(persona);
}
}
public class Person
{
public string Name { get; set; }
public List<string> Abilities;
public Person(string name,List<string> abilities)
{
Name = name;
Abilities = abilities;
}
public override string ToString()
{
string retVal = $"Name: {Name}\n";
foreach (var ability in Abilities)
{
retVal += $"Ability : {ability}\n";
}
return retVal;
}
}

for (int i = 0; i < 100; i++)
{
if (elo.ReadObjMask(i) > 0)
{
// Create a new listin here
eigenschaften = new List<string>();
var iRet = elo.PrepareObjectEx(0, 0, i);
maskenname = elo.ObjMName();
if (maskenname != "")
{
for (int e = 0; e < 50; e++)
{
string eigenschaft = elo.GetObjAttribName(e);
if (eigenschaft != "" && eigenschaft != "-")
{
eigenschaften.Add(eigenschaft);
}
}
allMasks.Add(maskenname);
}
else
{
// Do nothing
}
EloMask emask = new EloMask(maskenname, eigenschaften);
staticVariables.allMask.Add(emask);
}
}

Split string to list of object

I have inputs like following:
"10+18+12+13"
"10+18-12+13"
"2-5"
e.g. number followed by a "+" or "-"
I created class MathOper
public class MathOper
{
public int Num { get; set; }
public string Oper { get; set; } //this display the number will be operated.
}
I want to return list of MathOper as following
"10+18-12+13" will return
new MathOper(){Num=10,"+"}
new MathOper(){Num=18,"+"}
new MathOper(){Num=12,"-"}
new MathOper(){Num=13,"+"}
I tried to code that by this way:
public class MathOperCreator
{
private readonly string _mathString;//8+2-3
public MathOperCreator(string mathString)
{
this._mathString = mathString.Trim();
}
public List<MathOper> Create()
{
var lMo = new List<MathOper>();
int l = this._mathString.Length;//5
for (int i = 0; i < l; i = i + 2)
{
char n = _mathString[i];
int n1 = int.Parse(n.ToString(CultureInfo.InvariantCulture));
string o1 = "+";
if (i > 0)
{
o1 = _mathString[i - 1].ToString(CultureInfo.InvariantCulture);
}
var mo = new MathOper { Num = n1, Oper = o1 };
lMo.Add(mo);
}
return lMo;
}
}
I found that it is only for number with one char, if the number is two char ,such as 18 , it doesn't work.
Please advice how implement described functionality?

This is a tested Solution
//Model class
public class MathOperation
{
public Int32 Num { get; set; }
public String Operation { get; set; }
}
String testData = "10+18+12-13";
String[] GetNumbers = testData.Split(new Char[] { '+', '-' });
String[] GetOperators = Regex.Split(testData, "[0-9]+");
//remove empty entries in operator
GetOperators = GetOperators.Where(x => !string.IsNullOrEmpty(x)).ToArray();
List<MathOperation> list = new List<MathOperation>();
MathOperation mathOperation = new MathOperation();
for (int i = 0; i < GetNumbers.Count(); i++)
{
mathOperation.Num = Convert.ToInt32(GetNumbers[i]);
mathOperation.Operation = (i>GetOperators.Length)? GetOperators[i] : null;
list.Add(mathOperation);
}
This will give a list like
{Num=10,"+"}
{Num=18,"+"}
{Num=12,"-"}
{Num=13,"null"} //as in my test string there is no char after 13
if you dont want a null always a + then
mathOperation.Operation = (i>GetOperators.Length)? GetOperators[i] : "+";
then This will give a list like
{Num=10,"+"}
{Num=18,"+"}
{Num=12,"-"}
{Num=13,"+"} //as in my test string there is no char after 13

This works for me.
//you can change in to MathOper
List<Tuple<int, char>> result = new List<Tuple<int, char>>();
string _mathString = "2-2+10-13"; //Test
char sign = '-';
if (_mathString[0] != '-') //checking the first sign
{
sign = '+';
}
while (_mathString.Length > 0)
{
int nextPl = _mathString.IndexOf('+');
int nextMn = _mathString.IndexOf('-');
if (nextPl == -1 && nextMn == -1) //condition when _mathString contains only number
{
result.Add(new Tuple<int, char>(int.Parse(_mathString), sign));
break;
}
else
{
//getting the end position of first number
int end = nextPl == -1 ? nextMn : (nextMn == -1 ? nextPl : (Math.Min(nextPl, nextMn)));
//retrieving first number
result.Add(new Tuple<int, char>(int.Parse(_mathString.Substring(0, end)), sign));
_mathString = _mathString.Remove(0, end);
//retrieving next sign
sign = _mathString[0];
_mathString = _mathString.Remove(0, 1);
}
}

Try this, I think it works the way you wanted: (Easy to understand solution but not optimal)
public class MathOper
{
public int Num { get; set; }
public string Oper { get; set; } //this display the number will be operated.
}
public class MathOperCreator
{
public readonly string _mathString;//8+2-3
public MathOperCreator(string mathString)
{
this._mathString = mathString.Trim();
}
public List<MathOper> Create()
{
var lMo = new List<MathOper>();
int l = this._mathString.Length;//5
string _mathStringTemp;
char[] charArr = _mathString.ToCharArray();
if (charArr[0] != '+' || charArr[0] != '-')
{
_mathStringTemp = "+"+_mathString;
} else
{
_mathStringTemp = _mathString;
}
char[] delimitersNumb = new char[] { '+', '-' };
string[] numbers = _mathStringTemp.Split(delimitersNumb,
StringSplitOptions.RemoveEmptyEntries);
string[] operators = new string[numbers.Length];
int count = 0;
foreach (char c in _mathStringTemp)
{
if (c == '+' || c == '-')
{
operators[count] = c.ToString();
count++;
}
}
for(int i=0; i < numbers.Length; i++)
{
lMo.Add(new MathOper(){Num = int.Parse(numbers[i]), Oper = operators[i]});
Console.WriteLine(operators[i]+" "+numbers[i]);
}
return lMo;
}
}

I need to remove items from a list

I am making a program that takes user input and populates that into a list. That part is working great. However the user needs the ability to edit or delete his/her input. I cannot figure out how to remove an item from the list. Here is the code for populating the list:
[Serializable]
class Recipient
{
public string Fname { get; set; }
public string MInit { get; set; }
public string Lname { get; set; }
public string Suffix { get; set; }
public string Amount { get; set; }
public string Message { get; set; }
public string Custom { get; set; }
public string CardType { get; set; }
} protected void btnToCart_Click(object sender, EventArgs e)
{
if (ValidateInput("Card Information"))
{ SetUI("Your Shopping Cart"); }
else
{
return;
}
Recipient recipients = new Recipient();
List<string> FName = (List<string>)ViewState["recipientList"];
List<string> MInit = (List<string>)ViewState["recipientList"];
List<string> LName = (List<string>)ViewState["recipientList"];
List<string> Suffix = (List<string>)ViewState["recipientList"];
List<string> Amount = (List<string>)ViewState["recipientList"];
List<string> Message = (List<string>)ViewState["recipientList"];
List<string> Custom = (List<string>)ViewState["recipientList"];
List<string> CardType = (List<string>)ViewState["recipientList"];
if (FName == null && MInit == null && LName == null && Suffix == null && Amount == null &&
Message == null && Custom == null && CardType == null)
{
FName = new List<string>();
MInit = new List<string>();
LName = new List<string>();
Suffix = new List<string>();
Amount = new List<string>();
Message = new List<string>();
Custom = new List<string>();
CardType = new List<string>();
}
recipients.Fname = txtFName.Text;
recipients.MInit = txtMInit.Text;
recipients.Lname = txtLName.Text;
recipients.Suffix = ddlSuffix1.SelectedItem.ToString();
recipients.Amount = txtAmount.Text;
recipients.Message = ddlMessage.SelectedItem.ToString();
recipients.Custom = txtCustom.Text;
recipients.CardType = lblImage.Text;
FName.Add(recipients.Fname);
MInit.Add(recipients.MInit);
LName.Add(recipients.Lname);
Suffix.Add(recipients.Suffix);
Amount.Add(recipients.Amount);
Message.Add(recipients.Message);
Custom.Add(recipients.Custom);
CardType.Add(recipients.CardType);
ViewState["recipientList"] = FName;
ViewState["recipientList"] = MInit;
ViewState["recipientList"] = LName;
ViewState["recipientList"] = Suffix;
ViewState["recipientList"] = Amount;
ViewState["recipientList"] = Message;
ViewState["recipientList"] = Custom;
ViewState["recipientList"] = CardType;
if (FName.Count == 1 && MInit.Count == 1 && LName.Count == 1 && Suffix.Count == 1)
{
lblCartName.Text = FName[0] + " " + MInit[0] + " " + LName[0] + " " + Suffix[0];
lnkEdit1.Visible = true;
}
if (Amount.Count == 1 && Message.Count == 1 && Custom.Count == 1)
{
lblCartAmount.Text = "$" + Amount[0] + ".00";
if (txtCustom.Text == string.Empty)
{
lblCartMessage.Text = Message[0];
}
else
{
lblCartMessage.Text = Custom[0];
}
}
Yes there is more to it but anyways, once the user clicks the next button then a summary is displayed to the user with all input information. There is also two linkbuttons on the form that gives the user the choice of editing or deleting. I have tried variations of:
FName.Remove(recipients.fname); and FName.RemoveAt(0);for example and none of these have worked. So that is my problem, any help would be greatly appreciated. Thanks

Like #rich.okelly wrote you overwrite your ViewState:
Use something like this:
List<string> FName = (List<string>)ViewState["recipientListFName"];
List<string> MInit = (List<string>)ViewState["recipientListMInit"];
List<string> LName = (List<string>)ViewState["recipientListLName"];
List<string> Suffix = (List<string>)ViewState["recipientListSuffix"];
List<string> Amount = (List<string>)ViewState["recipientListAmount"];
List<string> Message = (List<string>)ViewState["recipientListMessage"];
List<string> Custom = (List<string>)ViewState["recipientListCustom"];
List<string> CardType = (List<string>)ViewState["recipientListCardType"];

How do you get a user's country name in C#?

I am currently using geolocation to get the user's country name. Here is my code:
navigator.geolocation.getCurrentPosition(function (pos) {
var latlng = pos.coords.latitude + "," + pos.coords.longitude;
var apiurl = 'http://maps.google.com/maps/geo?output=json&sensor=false&q=' + latlng;
var yqlqry = encodeURIComponent('select * from json where url="' + apiurl + '"');
var yqlurl = 'http://query.yahooapis.com/v1/public/yql?q=' + yqlqry + '&format=json&callback=?';
$.getJSON(yqlurl, function (data) {
var countryName = data.query.results.json.Placemark.AddressDetails.Country.CountryName;
var newCountryName = countryName.toLowerCase();
if (newCountryName == "united states")
newCountryName = "us";
else if (newCountryName == "england" || newCountryName == "ireland" || newCountryName == "scotland" || newCountryName == "wales" || newCountryName == "northern ireland")
newCountryName = "uk";
else if (newCountryName == "australia")
newCountryName = "au";
else if (newCountryName == "canada")
newCountryName = "ca";
else
newCountryName = "world";
$('a[title = "' + newCountryName + '"]').trigger('click');
});
});
I would rather use something on the server side. Does anyone know if you can get the user's country name in C#?

On the server side, the only thing you can reply upon is the IP address, which you can use to perform a location lookup. There are free databases out there of IP address-to-location mappings, or you can use HostIP.info.
Look at https://stackoverflow.com/questions/372591/how-to-get-city-country-and-country-code-for-a-particular-ip-address-in-asp-ne for more info.

I did this for WP7, but code is almost the same in standard.net framework: http://www.felicepollano.com/2012/01/11/AnImplementationOfICivicAddressResolverForWP7.aspx
the class doing the job is below. Just remove ICivicAddressResolver that is a WP7 dependency and create your own interface.
public class AddressResolver:ICivicAddressResolver
{
string language = "en-GB";
public AddressResolver()
{
}
public AddressResolver(string language)
{
this.language = language;
}
[DataContract]
public class AddressInfo
{
[DataMember(Name = "formatted_address")]
public string FormattedAddress { get; set; }
}
[DataContract]
public class ResultInfo
{
[DataMember(Name = "results")]
public AddressInfo[] Info { get; set; }
}
readonly string URITemplate = "http://maps.googleapis.com/maps/api/geocode/json?latlng={0},{1}&sensor=true&language={2}";
#region ICivicAddressResolver Members
public CivicAddress ResolveAddress(GeoCoordinate coordinate)
{
throw new NotImplementedException("Use async version instead");
}
public void ResolveAddressAsync(GeoCoordinate coordinate)
{
WebClient client = new WebClient();
client.Encoding = Encoding.UTF8;
client.DownloadStringCompleted += (s, e) =>
{
if (e.Error == null)
{
var ainfo = ReadToObject<ResultInfo>(e.Result);
ResolveAddressCompleted(this, new ResolveAddressCompletedEventArgs(ToCivic(ainfo),e.Error,false,null));
}
else
{
ResolveAddressCompleted(this, new ResolveAddressCompletedEventArgs(new CivicAddress(), e.Error, false, null));
}
};
client.DownloadStringAsync(new Uri(GetFormattedUri(coordinate)));
}
private CivicAddress ToCivic(ResultInfo ainfo)
{
List<string> res = new List<string>();
foreach (var single in ainfo.Info)
{
res.Add(single.FormattedAddress);
}
if (res.Count > 0)
return new CivicAddress() { AddressLine1 = res[0] };
else
return new CivicAddress() { AddressLine1 = "#UNKNOWN#" };
}
public event EventHandler<ResolveAddressCompletedEventArgs> ResolveAddressCompleted = delegate { };
#endregion
private string GetFormattedUri(GeoCoordinate coord)
{
return string.Format(CultureInfo.InvariantCulture, URITemplate, coord.Latitude, coord.Longitude,language);
}
public static T ReadToObject<T>(string json) where T : class
{
MemoryStream ms = new MemoryStream(Encoding.UTF8.GetBytes(json));
DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(T));
T res = ser.ReadObject(ms) as T;
ms.Close();
return res;
}
}

Why don't you try IP2Location's API ?
You could just pass your ipaddress like this.
http://api.ip2location.com/?ip=145.228.219.221&key=demo
More info at
http://www.ip2location.com/ip-country-web-service.aspx

Don't know if this will help but in local this
CultureInfo.CurrentCulture.Name
return something like "en-GB" or "fr-FR" depending of your current locale