Why does TypeConverter not obey Cultures? - c#

I have a CSV Reader, so I have a generic casting method. It it, I do this:
try
{
TypeConverter converter = TypeDescriptor.GetConverter(type);
if (converter != null)
{
result = converter.ConvertFromString(null, culture, value);
return true;
}
result = type.GetDefault();
return true;
}
catch
{
result = type.GetDefault();
return false;
}
However if I pass:
type: int
value: "123.024"
culture: de-DE
The converter always fails and returns 0, instead of correctly treating . as a thousands separator.
Anyone know how to get it to work?

Because the Int32Converter calls Int32.Parse internally, and Int32.Parse does not support thousands separators in the string passed to it.
More specifically, Int32.Parse format described below:
The s parameter contains a number of the form:
[ws][sign]digits[ws]
Items in square brackets ([ and ]) are optional. The following table
describes each element. Element Description
ws Optional white space.
sign An optional sign
digits A sequence of digits ranging from 0 to
9.
The s parameter is interpreted using the NumberStyles.Integer style. In addition to decimal digits, only leading and trailing spaces
together with a leading sign are allowed. To explicitly define the
style elements that can be present in s, use either the
Int32.Parse(String, NumberStyles) or the
Int32.Parse(String, NumberStyles, IFormatProvider) method.
The s parameter is parsed using the formatting information in a NumberFormatInfo object initialized for the current system culture.
For more information, see CurrentInfo. To parse a string using the
formatting information of some other culture, use the
Int32.Parse(String, NumberStyles, IFormatProvider) method.
If you were calling Int32.Parse directly, you could just call the overload that accepts a NumberStyles enum and create a composite value with the flags you want. E.g:
Int32.Parse(value, NumberStyles.Integer | NumberStyles.AllowThousands);
However, neither GetConverter() nor Int32Converter have any means of overriding the default NumberStyles of Int32.Parse, so you will either need a special case for ints or you will have to ensure that the strings passed to this function do not contain thousands separators.

Related

Convert.ToDecimal from input string ignores dots but accepts comma [duplicate]

This question already has answers here:
String to decimal conversion: dot separation instead of comma
(8 answers)
Closed 3 years ago.
I have this small piece of code:
using System;
using System.Globalization;
namespace project
{
class conditionalStatements
{
static void Main(string[] args)
{
Console.WriteLine("Enter a number greater than 45.2");
string answer = Console.ReadLine();
decimal answer_decimal = Convert.ToDecimal(answer);
// decimal answer_decimal = Decimal.Parse(answer);
decimal compareValue = 45.2m;
Console.WriteLine(answer_decimal);
//prints 452
if(Decimal.Compare(answer_decimal, compareValue) > 0){
// stuff
}
else{
// should enter here
}
}
}
}
The problem is that since both the method Convert.ToDecimal() and Decimal.Parse() ignore the dot notation of decimal values (or at least that's what's happening to me) the number is interpreted as 452 instead of 45.2. No matter how many dots I input. In fact, if I were to enter:
45......2
the converted value still would be converted to 452. Only if I use the comma, then the converted number is correctly interpreted as 45.2 and I am able to enter the else condition.
I did not change the NumberFormatInfo.CurrencyDecimalSeparator. I left it as default '.'
Convert input string to decimal with a given culture that treats dot as decimal separator:
decimal answer_decimal = Convert.ToDecimal(answer, new CultureInfo("en-US"));
You could try something like the code below:
decimal answer_decimal;
while(!decimal.TryParse(answer, out answer_decimal)){
Console.WriteLine("Value entered could not be converted.");
}
decimal compareValue = 45.2m;
Console.WriteLine(answer_decimal);
//prints 452
if(Decimal.Compare(answer_decimal, compareValue) > 0){
// stuff
}
else{
// should enter here
}
This way you prevent the program from crashing if the conversion is not possible.
If you want to use a specific culture you can do so by using an overload of decimal.TryParse as follows:
decimal.TryParse(answer, System.Globalization.NumberStyles.Any, new System.Globalization.CultureInfo("EN-us"), out answer_decimal);
Is your culture set to Dari?
I think the applicable NumberFormatInfo property would be NumberDecimalSeparator, not CurrencyDecimalSeparator. decimal.Parse(), called directly or via Convert.ToDecimal(), would have no idea currency is what's being parsed unless a NumberStyles value with one of the *Currency* flags were passed.
When an overload of decimal.Parse() is called that does not accept a NumberStyles parameter it defaults to NumberStyles.Number. This composite style includes the NumberStyles.AllowDecimalPoint style, the documentation for which states (emphasis mine)...
If the NumberStyles value includes the AllowCurrencySymbol flag and the parsed string includes a currency symbol, the decimal separator character is determined by the CurrencyDecimalSeparator property. Otherwise, the decimal separator character is determined by the NumberDecimalSeparator property.
Now, are there actually any cultures that use different decimal separators for numbers and currency? Let's find out...
CultureInfo.GetCultures(CultureTypes.AllCultures)
.Where(culture => culture.NumberFormat.CurrencyDecimalSeparator != culture.NumberFormat.NumberDecimalSeparator);
On .NET Framework v4.7.2 that yields a small number of cultures...
fr-CH
kea
kea-CV
mr
mr-IN
prs
prs-AF
pt-CV
Tweaking that LINQ query to account for the specific behavior you're seeing (currency decimal separator is ".", number decimal separator is ",", number group separator is ".")...
CultureInfo.GetCultures(CultureTypes.AllCultures)
.Where(culture => culture.NumberFormat.CurrencyDecimalSeparator == ".")
.Where(culture => culture.NumberFormat.NumberDecimalSeparator == ",")
.Where(culture => culture.NumberFormat.NumberGroupSeparator == ".");
...narrows it down to two Dari cultures...
prs
prs-AF
Sure enough, if I change my culture to Dari beforehand...
CultureInfo.CurrentCulture = new CultureInfo("prs");
...on my system your code behaves exactly as you described. If you don't want to use your culture's separators the solution, of course, is to specify at the system, thread, or method level a specific or custom culture with the separators you do want.

converting to string return null

while am trying to convert the return value of add method to string it is not returning any value in console.while i remove the tostring method it is returning value.if i write any character inside the double quote it is showing in console.
what is happening while am calling tostring method?
if i didn't put any double quote as parameter it is showing compile time error like (specify culture of string)
what is the purpose of specifying culture while converting int to string?
i think i can convert integer value to string by calling tostring method,why can't i do conversion in this scenario?
private static int Add(int x,int y)
{
return x+y;
}
static void Main(string[] args)
{
Console.WriteLine(Add(23,54).ToString(""));
Console.ReadKey();
}
thanks.
It's all about implementation;
From Int32.ToString(string)
If format is null or an empty string (""), the return value of this
instance is formatted with the general numeric format specifier ("G").
That's why .ToString("") is equal to .ToString() because
From Int32.ToString()
The ToString() method formats an Int32 value in the default ("G", or
general) format by using the NumberFormatInfo object of the current
culture.
I tried all cultures to format with .ToString("") and no culture returns null or empty string.
foreach (var c in CultureInfo.GetCultures(CultureTypes.AllCultures))
{
if((77).ToString("G", c) != "77")
Console.WriteLine (c.Name);
}
Blue line probably there is a plugin (maybe ReSharper) that warn you to use another overloads that takes CultureInfo as a parameter for example.
Use ToString with no parameters
Add(23,54).ToString()
Using the parameter you specified you set a culture for the string conversion.
More here.
simply specify your culture of string as string.empty
Console.WriteLine(Add(23,54).ToString(string.Empty));
Console.ReadKey();
Culture Name:"" (empty string)
Culture Identifier:0x007F
Language-Country/Region:invariant culture
http://msdn.microsoft.com/en-us/library/system.globalization.cultureinfo%28v=vs.71%29.aspx
string.Empty is a read-only field whereas "" is a compile time constant.some Places they behave differently.

Decimal to string with thousand's separators?

Consider a Decimal value:
Decimal value = -1234567890.1234789012M;
i want to convert this Decimal value to a string, and include "thousands separators".
Note: i don't want to include thousand's separators, i want to include digit grouping. The difference is important for cultures that don't group numbers into thousands, or don't use commas to separate groups
Some example output with different standard formatting strings, on my computer, with my current locale:
value.ToString() = -1234567890..1234789012 (Implicit General)
value.ToString("g") = -1234567890..1234789012 (General)
value.ToString("d") = FormatException (Decimal whole number)
value.ToString("e") = -1..234568e++009 (Scientific)
value.ToString("f") = -1234567890..123 (Fixed Point)
value.ToString("n") = -12,,3456,,7890..123 (Number with commas for thousands)
value.ToString("r") = FormatException (Round trippable)
value.ToString("c") = -$$12,,3456,,7890..123 (Currency)
value.ToString("#,0.#") = -12,,3456,,7890..1
What i want (depending on culture) is:
en-US -1,234,567,890.1234789012
ca-ES -1.234.567.890,1234789012
gsw-FR -1 234 567 890,1234789012 (12/1/2012: fixed gws-FR to gsw-FR)
fr-CH -1'234'567'890.1234789012
ar-DZ 1,234,567,890.1234789012-
prs-AF 1.234.567.890,1234789012-
ps-AF 1،234،567،890,1234789012-
as-IN -1,23,45,67,890.1234789012
lo-LA (1234567,890.1234789012) (some debate if numbers should be "1,234,567,890")
qps-PLOC 12,,3456,,7890..1234789012
How can i convert a Decimal to a string, with digit groupings?
Update: Some more desired output, using my current culture of :
-1234567890M --> -12,,3456,,7890
-1234567890.1M --> -12,,3456,,7890..1
-1234567890.12M --> -12,,3456,,7890..12
-1234567890.123M --> -12,,3456,,7890..123
-1234567890.1234M --> -12,,3456,,7890..1234
-1234567890.12347M --> -12,,3456,,7890..12347
-1234567890.123478M --> -12,,3456,,7890..123478
-1234567890.1234789M --> -12,,3456,,7890..1234789
-1234567890.12347890M --> -12,,3456,,7890..1234789
-1234567890.123478901M --> -12,,3456,,7890..123478901
-1234567890.1234789012M --> -12,,3456,,7890..1234789012
Update: i tried peeking at how Decimal.ToString() manages to use the General format to show all the digits that it needs to show:
public override string ToString()
{
return Number.FormatDecimal(this, null, NumberFormatInfo.CurrentInfo);
}
except that Number.FormatDecimal is hidden somewhere:
[MethodImpl(MethodImplOptions.InternalCall)]
public static extern string FormatDecimal(decimal value, string format, NumberFormatInfo info);
So that's a dead end.
The ToString method on decimals by default uses the CultureInfo.CurrentCulture for the user's session, and thus varies based on whom is running the code.
The ToString method also accepts an IFormatProvider in various overloads. This is where you need to supply your culture-specific Formatters.
For instance, if you pass the NumberFormat for fr-CH, you can format things as that culture expects:
var culture = CultureInfo.CreateSpecificCulture("fr-CH");
Decimal value = -1234567890.1234789012M;
Console.WriteLine(value.ToString("##,#.###############", culture.NumberFormat));
Will output
-1'234'567'890.1234789012
Edit #3 - rewrote using custom formatters. This should do what you want based on the new updated question.
Edit #4 - Took all of your input, and ran this:
public void TestOutput()
{
PrintValue(-1234567890M);
PrintValue(-1234567890.1M);
PrintValue(-1234567890.12M);
PrintValue(-1234567890.123M);
PrintValue(-1234567890.1234M);
PrintValue(-1234567890.12347M);
PrintValue(-1234567890.123478M);
PrintValue(-1234567890.1234789M);
PrintValue(-1234567890.12347890M);
PrintValue(-1234567890.123478901M);
PrintValue(-1234567890.1234789012M);
}
private static void PrintValue(decimal value)
{
var culture = CultureInfo.CreateSpecificCulture("qps-PLOC");
Console.WriteLine(value.ToString("##,#.###############", culture.NumberFormat));
}
Gives output matching what you supplied:
--12,,3456,,7890
--12,,3456,,7890..1
--12,,3456,,7890..12
--12,,3456,,7890..123
--12,,3456,,7890..1234
--12,,3456,,7890..12347
--12,,3456,,7890..123478
--12,,3456,,7890..1234789
--12,,3456,,7890..1234789
--12,,3456,,7890..123478901
--12,,3456,,7890..1234789012
As pointed out by Joshua, this only works for some locales.
From the looks of it then, you need to pick the lesser of two evils: Knowing the precision of your numbers, or specifying formats for each culture. I'd wager knowing the precision of your numbers may be easier.
In which case, a previous version of my answer may be of use:
To explicitly control the number of decimal places to output, you can clone the number format provided by the culture and modify the NumberDecimalDigits property.
var culture = CultureInfo.CreateSpecificCulture("fr-CH");
Decimal value = -1234567890.1234789012M;
NumberFormatInfo format = (NumberFormatInfo)culture.NumberFormat.Clone();
format.NumberDecimalDigits = 30;
Console.WriteLine(value.ToString("n", format));
This outputs:
-1'234'567'890.123478901200000000000000000000
You can specify a custom pattern (the pattern will appropriately resolve to the culture specific method of grouping and the appropriate grouping and decimal separator characters). A pattern can have positive, negative and zero sections. The positive pattern is always the same but the negative pattern depends on the culture and can be retrieved from the NumberFormatInfo's NumberNegativePattern property. Since you want as much precision as possible, you need to fill out 28 digit placeholders after the decimal; the comma forces grouping.
public static class DecimalFormatters
{
public static string ToStringNoTruncation(this Decimal n, IFormatProvider format)
{
NumberFormatInfo nfi = NumberFormatInfo.GetInstance(format);
string[] numberNegativePatterns = {
"(#,0.############################)", //0: (n)
"-#,0.############################", //1: -n
"- #,0.############################", //2: - n
"#,0.############################-", //3: n-
"#,0.############################ -"};//4: n -
var pattern = "#,0.############################;" + numberNegativePatterns[nfi.NumberNegativePattern];
return n.ToString(pattern, format);
}
public static string ToStringNoTruncation(this Decimal n)
{
return n.ToStringNoTruncation(CultureInfo.CurrentCulture);
}
}
Sample output
Locale Output
======== ============================
en-US -1,234,567,890.1234789012
ca-ES -1.234.567.890,1234789012
hr-HR - 1.234.567.890,1234789012
gsw-FR -1 234 567 890,1234789012
fr-CH -1'234'567'890.1234789012
ar-DZ 1,234,567,890.1234789012-
prs-AF 1.234.567.890,1234789012-
ps-AF 1،234،567،890,1234789012-
as-IN -1,23,45,67,890.1234789012
lo-LA (1234567,890.1234789012)
qps-PLOC -12,,3456,,7890..1234789012
There is currently no locale that uses NegativeNumberFormat 4 (n -), so that case cannot be tested. But there's no reason to think it would fail.
You need to include the culture when formatting for your strings. You can either use String.Format and include the culture as the first parameter or use the object's ToString method and use the overload that takes a culture.
The following code produces the expected output (except for gws-FR, it couldn't find a culture with that string).
namespace CultureFormatting {
using System;
using System.Globalization;
class Program {
public static void Main() {
Decimal value = -1234567890.1234789012M;
Print("en-US", value);
Print("ca-ES", value);
//print("gws-FR", value);
Print("fr-CH", value);
Print("ar-DZ", value);
Print("prs-AF", value);
Print("ps-AF", value);
Print("as-IN", value);
Print("lo-LA", value);
Print("qps-PLOC", value);
}
static void Print(string cultureName, Decimal value) {
CultureInfo cultureInfo = new CultureInfo(cultureName);
cultureInfo.NumberFormat.NumberDecimalDigits = 10;
// Or, you could replace the {1:N} with {1:N10} to do the same
// for just this string format call.
string result =
String.Format(cultureInfo, "{0,-8} {1:N}", cultureName, value);
Console.WriteLine(result);
}
}
}
The above code produces the following output:
en-US -1,234,567,890.1234789012
ca-ES -1.234.567.890,1234789012
fr-CH -1'234'567'890.1234789012
ar-DZ 1,234,567,890.1234789012-
prs-AF 1.234.567.890,1234789012-
ps-AF 1،234،567،890,1234789012-
as-IN -1,23,45,67,890.1234789012
lo-LA (1234567,890.1234789012)
qps-PLOC --12,,3456,,7890..1234789012
If you're working with a multithreaded system, such as ASP.Net, you can change the thread's CurrentCulture property. Changing the thread's culture will allow all of the associated ToString and String.Format calls to use that culture.
Update
Since you're wanting to display all of the precision you're going to have to do a bit of work. Using NumberFormat.NumberDecimalDigits will work, except that if the value has less precision, the number will output with trailing zeros. If you need to make sure you display every digit without any extras, you will need to calculate the precision beforehand and set that before you convert it to a string. The StackOverflow question Calculate System.Decimal Precision and Scale may be able to help you determine the precision of the decimal.

Converting masked currency string using Decimal.TryParse

I'm having issue converting this string to a decimal. I tried to follow the documentation here with no luck: Decimal.TryParse Method
string stringVal = "-(3434343434.00)";
NumberStyles style = NumberStyles.AllowDecimalPoint | NumberStyles.AllowThousands |
NumberStyles.AllowParentheses | NumberStyles.AllowLeadingSign;
CultureInfo culture = CultureInfo.CreateSpecificCulture("en-US");
decimal value;
bool parseSuccess = decimal.TryParse(stringVal, style, culture, out value);
parseSuccess is returning false.
I think a - sign and parenthesis at the same time is not valid. -3434343434.00 is fine as is (3434343434.00) but -(3434343434.00) is not valid. -(3434343434.00) does not really make sense it is using 2 different methods to indicate a negative and as such is a bit redundant.
You have both () and a - sign in your string. This is incorrect and is why your string doesn't parse.
See the documentations for AllowParentheses:
AllowParentheses: Indicates that the numeric string can have one pair of parentheses enclosing the number. The parentheses indicate that the string to be parsed represents a negative number.

Thousand separated value to integer

I want to convert a thousand separated value to integer but am getting one exception.
double d = Convert.ToDouble("100,100,100");
is working fine and getting d=100100100
int n = Convert.ToInt32("100,100,100");
is getting one format exception
Input string was not in a correct format
Why?
try this:
int i = Int32.Parse("100,100,100", NumberStyles.AllowThousands);
Note that the Parse method will throw an exception on an invalid string, so you might also want to check out the TryParse method as well:
string s = ...;
int i;
if (Int32.TryParse(s, NumberStyles.AllowThousands, CultureInfo.InvariantCulture, out i))
{
// if you are here, you were able to parse the string
}
What Convert.ToInt32 is actually calling in your example is Int32.Parse.
The Int32.parse(string) method only allows three types of input: white space, a sign, and digits. In the following configuration [ws][sign]digits[ws] (in brackets are optional).
Since your's contained commas, it threw an exception.
Because you're supposed to specify a string containing a plain integer number (maybe preceded by +/- sign), with no thousands separator. You have to replace the separator befor passing the string to the ToInt32 routine.
You can't have separators, just numbers 0 thru 9, and an optional sign.
http://msdn.microsoft.com/en-us/library/sf1aw27b.aspx

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