We Keep Coding

How to put spaces on a bound enum title on picker

I am attaching enum to a picker and onSelect i am binding to the actual value of the enum, not its title.
My enum is as follows:
public enum Reason
{
AnnualLeave = 12,
Emergency = 23,
MaternityLeave = 34
}
My class uses the following to bind the enum title to the picker
public Reason ReasonSelectedOption { get; set; }
public ObservableCollection<Reason> ReasonDisplay
{
get => new ObservableCollection<Reason>(Enum.GetValues(typeof(Reason)).OfType<Reason>().ToList());
}
The actual picker
<Picker
ItemsSource="{Binding ReasonDisplay}"
SelectedItem="{Binding ReasonSelectedOption}"
Title="Please Select"
HorizontalOptions="FillAndExpand" />
Everything works fine except in the actual picker, the options appear as AnnualLeave and MaternityLeave which is what's expected from my code but i want them to appear as Annual Leave and Maternity Leave (with the space inbetween) preserving the selecteditem value
Current case: When user selects AnnualLeave, selectedItem value is 12, if i convert to string the selected value becomes 0.
I am simply asking how to put spaces inbetween the enum options and also preserve the SelectedItem integer value

Here you have to keep in mind the internationalisation.
Even if you don't have localised texts now, you may have to support it in the future. So, keeping that in mind, you won't need simply to "split" the string, but to take a specific text from somewhere (i.e. translate it according to the culture).
You can achieve it with the help of some attributes, extension methods and some clever binding.
Let's say that you want to have a picker with 2 options - what is the property type. The PropertyType is an enum, that looks like this:
public enum PropertyType
{
House,
Apartment
}
Since the built-in Description attribute can't translate texts for us, we can use a custom attribute to assign a specific text to an enum type, like this:
public enum PropertyType
{
[LocalizedDescription(nameof(R.SingleFamilyHouse))]
House,
[LocalizedDescription(nameof(R.ApartmentBuilding))]
Apartment
}
The attribute code looks like this:
public class LocalizedDescriptionAttribute : DescriptionAttribute
{
private readonly ResourceManager resourceManager;
private readonly string resourceKey;
public LocalizedDescriptionAttribute(string resourceKey, Type resourceType = null)
{
this.resourceKey = resourceKey;
if (resourceType == null)
{
resourceType = typeof(R);
}
resourceManager = new ResourceManager(resourceType);
}
public override string Description
{
get
{
string description = resourceManager.GetString(resourceKey);
return string.IsNullOrWhiteSpace(description) ? $"[[{resourceKey}]]" : description;
}
}
}
R is my resx file. I have created a Resources folder and inside it I have 2 resx files - R.resx (for English strings) & R.de.resx (for German translation). If you don't want to have internationalisation now, you can change the implementation to get your strings from another place. But it is considered a good practice to always use a resx file, even if you only have 1 language. You never now what tomorrow may bring.
Here is my structure:
The idea behind LocalizedDescriptionAttribute class is that the built-in Description attribute isn't very useful for our case. So we'll have to take the resource key that we have provided it, translates and to override the Description attribute, which later we will reference.
Now we need to obtain the localised description text with this helper method:
public static class EnumExtensions
{
public static string GetLocalizedDescriptionFromEnumValue(this Enum value)
{
return !(value.GetType()
.GetField(value.ToString())
.GetCustomAttributes(typeof(LocalizedDescriptionAttribute), false)
.SingleOrDefault() is LocalizedDescriptionAttribute attribute) ? value.ToString() : attribute.Description;
}
}
Now, when we create the bindings for the Picker, we won't just use a simple Enum, but a specific PropertyTypeViewModel, which will have 2 properties - the Enum itself and a Name that will be displayed.
public class PropertyTypeViewModel : BaseViewModel
{
private string name;
public string Name
{
get => name;
set => SetValue(ref name, value);
}
private PropertyType type;
public PropertyType Type
{
get => type;
set => SetValue(ref type, value);
}
public PropertyTypeViewModel()
{
}
public PropertyTypeViewModel(PropertyType type)
: this()
{
Type = type;
Name = type.GetLocalizedDescriptionFromEnumValue();
}
}
The important line is the last one - Name = type.GetLocalizedDescriptionFromEnumValue();
The final thing that is left is to set your Picker's ItemsSource to your collection of PropertyTypeViewModels and ItemDisplayBinding to be pointing to the Name property - ItemDisplayBinding="{Binding Name}"
That's it - now you have a Picker with dynamic localised strings.

You could use a converter
public class EnumToStringConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
if (value == null) return null;
var valueAsString = value.ToString();
valueAsString = valueAsString.SplitCamelCase();
return valueAsString;
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}
And for the SplitCamelCase I wrote this but I'm sure there are cleaner options:
public static string SplitCamelCase(this string str)
{
string result = "";
for (int i = 0; i < str.Count(); i++)
{
var letter = str[i];
var previousLetter = i != 0 ? str[i - 1] : 'A';
if (i != 0 && char.IsUpper(previousLetter) == false && char.IsUpper(letter)) result = result + " " + letter;
else result = result + letter;
}
return result;
}
Then just used it like so:
<TextBlock Text="{Binding Converter={StaticResource EnumToStringConverter}}"/>

Enforcing static class constants as a data type

I have a static class with constants. I am looking for options to create a method which takes a dictionary as an argument and enforcing the key to be one of the constants from the static class.Here is my static class with constants.
Here is what I am trying to do
And here is what I am trying to enforce

From the sound of it, an Enum would be more suited to what you're trying to do.
public enum MyConstants
{
FirstName,
LastName,
Title
}
public void CreateMe(Dictionary<MyConstants, string> propertyBag)
{
...
}
UPDATED
You could combine this with attributes to associate each enum with a specific string like so:
public enum PropertyNames
{
[Description("first_name")]
FirstName,
[Description("last_name")]
LastName,
[Description("title")]
Title
}
The value of each description attribute associated with each enum value could easily be grabbed via an extension method, like so:
public static class EnumExtensions
{
public static string GetDescription(this Enum value)
{
FieldInfo fieldInfo = value.GetType().GetField(value.ToString());
DescriptionAttribute[] attributes =
(DescriptionAttribute[])fieldInfo.GetCustomAttributes(
typeof(DescriptionAttribute),
false);
if (attributes != null &&
attributes.Length > 0)
return attributes[0].Description;
else
return value.ToString();
}
}
Then in your "CreateMe"-method you can get the description and value of each dictionary entry by doing something similar to this:
void CreateMe(Dictionary<PropertyNames, string> propertyBag)
{
foreach (var propertyPair in propertyBag)
{
string propertyName = propertyPair.Key.GetDescription();
string propertyValue = propertyPair.Value;
}
}

Even though this has been already answered, there is another approach, like so:
public class MyOwnEnum
{
public string Value { get; private set; }
private MyOwnEnum(string value)
{
Value = value;
}
public static readonly MyOwnEnum FirstName = new MyOwnEnum("Firstname");
public static readonly MyOwnEnum LastName = new MyOwnEnum("LastName");
}
It behaves same way like Enum and can be used in your code with same syntax. I cannot give credit to whoever came up with it, but I believe I came upon it when searching for Enums with multiple values.

With strings you can't enforce fact that keys come from limited set of vialues compile time.
Use enum or custom class (possibly with implicit conversion to string) instead.

Parse StringValueAttribute to return Enum

I currently have a windows phone 8.1 runtime project with enums that use a string value attribute. I want to be able to get an enum value by using the string value attribute, for example use "world" to get the enum value of summer. I am using Windows phone 8.1 runtime so most methods that I have found do not work.
Thanks in advance.
public enum test
{
[StringValue("hello")]
school,
[StringValue("world")]
summer,
[StringValue("fall")]
car
}
public class StringValueAttribute : Attribute
{
private string _value;
public StringValueAttribute(string value)
{
_value = value;
}
public string Value
{
get { return _value; }
}
}

To get to your Attributes you will need to use a method/extension. Folowing this question and answer you can make such a thing:
public class StringValueAttribute : Attribute
{
private string _value;
public StringValueAttribute(string value)
{
_value = value;
}
public string Value
{
get { return _value; }
}
public static string GetStringValue(Enum value)
{
Type type = value.GetType();
FieldInfo fi = type.GetRuntimeField(value.ToString());
return (fi.GetCustomAttributes(typeof(StringValueAttribute), false).FirstOrDefault() as StringValueAttribute).Value;
}
}
Then using this line of code:
string stringTest = StringValueAttribute.GetStringValue(test.summer);
will give a result of "world". (Opposite what you wanted, but hopefuly will give you an idea how to deal with the problem).
Depending on what you want to achieve, you can probably use different methods linke: using Dictionary, struct, properties and probably different ways.
As for parsing Enum values you can achieve it like this:
test testValue = test.summer;
string testString = testValue.ToString();
test EnumValue = (test)Enum.Parse(typeof(test), testString);
EDIT
If you want to get enum from attribute, then this method (probably should be improved) should do the job:
public static T GetFromAttribute<T>(string attributeName)
{
Type type = typeof(T);
return (T)Enum.Parse(typeof(T), type.GetRuntimeFields().FirstOrDefault(
x => (x.CustomAttributes.Count() > 0 && (x.CustomAttributes.FirstOrDefault().ConstructorArguments.FirstOrDefault().Value as string).Equals(attributeName))).Name);
}
Usage:
test EnumTest = StringValueAttribute.GetFromAttribute<test>("world");

Creating enums having Key Value as string

I know following syntax is possible with enum, and one can get value by parsing it in int or char.
public enum Animal { Tiger=1, Lion=2 }
public enum Animal { Tiger='T', Lion='L' }
Although following syntax is also right
public enum Anumal { Tiger="TIG", Lion="LIO"}
How do I get the value in this case? If I convert it using ToString(), I get the KEY not the VALUE.

If you really insist on using enum to do this, you can do it by having a Description attribute and getting them via Reflection.
public enum Animal
{
[Description("TIG")]
Tiger,
[Description("LIO")]
Lion
}
public static string GetEnumDescription(Enum value)
{
FieldInfo fi = value.GetType().GetField(value.ToString());
DescriptionAttribute[] attributes =
(DescriptionAttribute[])fi.GetCustomAttributes(
typeof(DescriptionAttribute),
false);
if (attributes != null &&
attributes.Length > 0)
return attributes[0].Description;
else
return value.ToString();
}
Then get the value by string description = GetEnumDescription(Animal.Tiger);
Or by using extension methods:
public static class EnumExtensions
{
public static string GetEnumDescription(this Enum value)
{
FieldInfo fi = value.GetType().GetField(value.ToString());
DescriptionAttribute[] attributes =
(DescriptionAttribute[])fi.GetCustomAttributes(
typeof(DescriptionAttribute),
false);
if (attributes != null &&
attributes.Length > 0)
return attributes[0].Description;
else
return value.ToString();
}
}
Then use it by string description = Animal.Lion.GetEnumDescription();

You can't use strings in enums. Use one or multiple dictionaries istead:
Dictionary<Animal, String> Deers = new Dictionary<Animal, String>
{
{ Animal.Tiger, "TIG" },
{ ... }
};
Now you can get the string by using:
Console.WriteLine(Deers[Animal.Tiger]);
If your deer numbers are in line ( No gaps and starting at zero: 0, 1, 2, 3, ....) you could also use a array:
String[] Deers = new String[] { "TIG", "LIO" };
And use it this way:
Console.WriteLine(Deers[(int)Animal.Tiger]);
Extension method
If you prefer not writing every time the code above every single time you could also use extension methods:
public static String AsString(this Animal value) => Deers.TryGetValue(value, out Animal result) ? result : null;
or if you use a simple array
public static String AsString(this Animal value)
{
Int32 index = (Int32)value;
return (index > -1 && index < Deers.Length) ? Deers[index] : null;
}
and use it this way:
Animal myAnimal = Animal.Tiger;
Console.WriteLine(myAnimal.AsString());
Other possibilities
Its also possible to do the hole stuff by using reflection, but this depends how your performance should be ( see aiapatag's answer ).

That is not possible, the value of the enum must be mapped to a numeric data type. (char is actually a number wich is wirtten as a letter)
However one solution could be to have aliases with same value such as:
public enum Anumal { Tiger=1, TIG = 1, Lion= 2, LIO=2}
Hope this helps!

This isn't possible with Enums. http://msdn.microsoft.com/de-de/library/sbbt4032(v=vs.80).aspx
You can only parse INT Values back.
I would recommend static members:
public class Animal
{
public static string Tiger="TIG";
public static string Lion="LIO";
}
I think it's easier to handle.

As DonBoitnott said in comment, that should produce compile error. I just tried and it does produce. Enum is int type actually, and since char type is subset of int you can assign 'T' to enum but you cannot assign string to enum.
If you want to print 'T' of some number instead of Tiger, you just need to cast enum to that type.
((char)Animal.Tiger).ToString()
or
((int)Animal.Tiger).ToString()

Possible alternative solution:
public enum SexCode : byte { Male = 77, Female = 70 } // ascii values
after that, you can apply this trategy in your class
class contact {
public SexCode sex {get; set;} // selected from enum
public string sexST { get {((char)sex).ToString();}} // used in code
}

How to set string in Enum C#?

I want to create string ENUM in c#.
Basically i wan't to set form name in Enum. When i open form in main page that time i want to switch case for form name and open that particular form.
I know ENUM allows only integer but i want to set it to string.
Any Idea?

Enum cannot be string but you can attach attribute and than you can read the value of enum as below....................
public enum States
{
[Description("New Mexico")]
NewMexico,
[Description("New York")]
NewYork,
[Description("South Carolina")]
SouthCarolina
}
public static string GetEnumDescription(Enum value)
{
FieldInfo fi = value.GetType().GetField(value.ToString());
DescriptionAttribute[] attributes =
(DescriptionAttribute[])fi.GetCustomAttributes(
typeof(DescriptionAttribute),
false);
if (attributes != null &&
attributes.Length > 0)
return attributes[0].Description;
else
return value.ToString();
}
here is good article if you want to go through it : Associating Strings with enums in C#

As everyone mentioned, enums can't be strings (or anything else except integers) in C#. I'm guessing you come from Java? It would be nice if .NET had this feature, where enums can be any type.
The way I usually circumvent this is using a static class:
public static class MyValues
{
public static string ValueA { get { return "A"; } }
public static string ValueB { get { return "B"; } }
}
With this technique, you can also use any type. You can call it just like you would use enums:
if (value == MyValues.ValueA)
{
// do something
}

Do this:
private IddFilterCompareToCurrent myEnum =
(IddFilterCompareToCurrent )Enum.Parse(typeof(IddFilterCompareToCurrent[1]),domainUpDown1.SelectedItem.ToString());
[Enum.parse] returns an Object, so you need to cast it.

Im not sure if I understood you corectly but I think you are looking for this?
public enum State { State1, State2, State3 };
public static State CurrentState = State.State1;
if(CurrentState == State.State1)
{
//do something
}

I don't think that enums are the best solution for your problem. As others have already mentionde, the values of an enum can only be integer values.
You could simply use a Dictionary to store the forms along with their name like:
Dictionary<string, Form> formDict = new Dictionary<string, Form>();
private void addFormToDict(Form form) {
formDict[form.Name] = form;
}
// ...
addFormToDict(new MyFirstForm());
addFormToDict(new MySecondForm());
// ... add all forms you want to display to the dictionary
if (formDict.ContainsKey(formName))
formDict[formName].Show();
else
MessageBox.Show(String.Format("Couldn't find form '{0}'", formName));

Either make the names of the Enum members exactly what you want and use .ToString(),
Write a function like this ...
string MyEnumString(MyEnum value)
{
const string MyEnumValue1String = "any string I like 1";
const string MyEnumValue2String = "any string I like 2";
...
switch (value)
{
case MyEnum.Value1:
return MyEnumValue1String;
case MyEnum.Value2:
return MyEnumValue2String;
...
}
}
Or use some dictionary or hash set of values and strings instead.

string enums don't exist in C#. See this related question.
Why don't you use an int (default type for enums) instead of a string?