I want to apply this:
private string _name;
public string name
{
get { return _name; }
set { _name = Fix(value); }
}
to all string the members of a class, and don't want to repeat the same code for all the class members.
An obvious solution would be to put that code on a class to handle the problem and declare all string members as: myString instead of string, however that would mean that I would have to access the main class members like this: email.fixed instead of just email.
So I was wondering, is there is some kind of template I can define and then apply easily?
You could create a Code Snippet for Visual Studio to handle building a property this way.
MSDN includes documentation on Creating a Code Snippet, which can include replacement parameters (the name).
You might want to research Aspect Oriented Programming, which allows you to easily do things like this.
http://www.codeproject.com/Articles/337564/Aspect-Oriented-Programming-Using-Csharp-and-PostS
Create a type with an implicit conversion to and from string:
public class FixedString
{
private string str;
public FixedString(string str){this.str = str;}
public static implicit operator FixedString(string str)
{
return new FixedString(Fix(str));
}
public static implicit operator string(FixedString fixed)
{
return fixed.str;
}
}
You can now create a property of this type, but treat it as if it's a string.
Create a regex replace and use Visual Studio's (v2012/2013) find and replace regex functionality.
For example let us say you have a field like this to change into a property
public string Name;
and you want to change it to have a backing field and the setter you desire.
private string _Name;
public string Name
{
get { return _Name; }
set { _Name = Fix(value); }
}
The find /replace regex pattern in Visual Studio to find is this
public\s+string\s([^;]+);
the replace pattern (with appropriate line spacings and tabs) is this
private string _$1;\r\n\r\n\tpublic string $1\r\n\t{\r\n\t\tget\r\n\t\t\t{ return _$1; }\r\n\t\tset\r\n\t\t\t{\r\n\t\t\t\t_$1 = Fix(value);\r\n\t\t\t}\r\n\t\t}
Then step through the finds and do a replace as needed within your class.
I have done similar to add INotifyChange method calls on blank properties created after doing the code snippet <tab><tab>prop action.
Related
This question already has answers here:
Any reason to use auto-implemented properties over manual implemented properties?
(7 answers)
Closed 5 years ago.
what is the different between writing the getter and setter directly like this:
public string Name {get; set;}
and like this:
private string _name;
public string Name
{
get
{
return this._name;
}
set
{
this._name = value;
}
}
I saw that in lots of codes. why they use a private member than a public getter and setter.
is it for performance or privacy or what is the point?
thank you.
what is the different between writing the getter and setter directly
like this
public string Name {get; set;}
They're essentially the same.
The code below you're basically creating the private field and providing both getters and setters for it, which of course does the intended idea. However, the language implementors decided they could make the life of a programmer easier by providing a shorter syntax where you can create a private field and at the same time provide a getter or setter or both.
private string _name;
public string Name
{
get
{
return this._name;
}
set
{
this._name = value;
}
}
So, in C# 3 they(language implementors) came up with the idea of making the syntax shorter by enabling a programmer to simultaneously create a private field and at the same time provide a getter or setter or both.
Behind the scenes, all that happens for the code below is the compiler creates a private field and also provides a getter and setter for it. So, basically, it's shorter more concise syntax to achieve the same task as the example above.
auto-implemented property
public string Name {get; set;}
There is none.
The thing is: auto-implemented properties weren't available until C# 3 (if you look at the documentation referenced: it goes back to VS 2008 which was released with C# 3), and not all code was written in the C# 3 era. Also, not all developers are aware of this feature. If I would stumble across this kind of code, I would rewrite it to use auto-implemented properties.
An property is just a short hand and will create at the background an public get method and a public set method and a private field to store the value.
Example Code
// example property
public string Name { get; set; }
// at run time it is the same as:
private string Name;
public string GetName(){
return this.Name;
}
public string SetName(string name){
this.Name = name;
}
See Image :
The sample class only has an property in code Name.
If you use Reflection to get all the members off the Sample class you will see that at run time set_name() and get_name() methods are generated.
These methods are not specified in in code.
Short answer, there isn't a difference. The compiler will convert the "auto" property to that style regardless, it's just saving you the writer a few keystrokes. It really only comes into play when you start working with DataBinding or having to do something else in the Set portion.
private string _name;
public string Name
{
get
{
return this._name;
}
set
{
this._name = value;OnPropertyChange();
}
}
In WPF/XAML/DataBinding, this would let anyone subscribed to this object know that a property with the name "Name" has changed and it should reflect so in the UI.
The first one is called an auto-implemented property.
Second one is used when you want to add some custom code logic that validates the value in your setter.
You can control what happens in the getter & setters, whereas if the member was public, the variable could be modified directly.
private string _name;
public string Name
{
get
{
return this._name + " likes chocolate";
}
set
{
this._name = value;
}
}
Here, your private _name always stays the same, but anyone accessing Name will get _name + " likes chocolate".
In the setter, you could do some validation.
Is there a way to do something like this in C#:
public class Class2 {
public string PropertyName1 { get
{
return this; //i mean "PropertyName1"
}
set {
this = value;
DoAdditionalFunction();
}
}
Because I need to call additional function in the "set" I need to have an extra private field like
private string _propertyName1;
public string PropertyName1 { get
{
return _propertyName1;
}
set {
_propertyName1= value;
DoAdditionalFunction();
}
I don't want to use additional property like _propertyName1. Is there a way to accomplish this or any best practices?
No - if you need any behaviour other than the most trivial "set a field, return the field value", you need to write "full" properties. Automatically implemented properties are only a shorthand for trivial properties.
Note that you haven't really got an "extra" private field, in terms of the actual contents of an object - it's just that you're explicitly declaring the private field instead of letting the compiler do it for you as part of the automatically implemented property.
(It's not clear what your first property is trying to do - setting this in a class is invalid, and you can't return this from a property of type string unless you've got a conversion to string...)
For C#, I hate writing out the variables and then writing out all the properties. Isn't there a way to select all variables, right click and create all the properties.
Right click on the field declaration, menu Refactor -> Encapsulate field and you go from
int n;
to
int n;
public int N
{
get { return n; }
set { n = value; }
}
Are you looking for a code refactoring tool? If so, check out ReSharper. It provides an easy to to turn simple field-backed properties into auto-properties, and vice versa.
If you simply don't want to write custom field-backed properties, you can use auto-properties, fpor example, like so:
public string MyProperty { get; set; } // generates an auto-property
which is equivalent to:
private string m_MyProperty;
public string MyProperty
{
get { return m_MyProperty; }
set { m_MyProperty = value; }
}
You can even make the accessibilty of the setter and getter difference:
public string MyProperty { get; private set; }
If you do choose to use auto-properties, be aware that you cannot access the underlying field, nor can you supply an implementation for just one portion (just the getter or just the setter). You can, however, make the property virtual.
If you're using C# 3.0 or above (VisualStudio 2008, essentially), you can use auto properties. While this isn't exactly what you're asking for, it should (hopefully) do the trick.
Rather than writing:
private string m_Name;
public string Name
{
get { return m_Name; }
set { m_Name = value; }
}
You can just write:
public string Name { get; set; }
This will give you quick, "dumb" (i.e. no retrieval or assignment logic) properties that can go on your class. If you find you need retrieval and assignment logic later, just come back and do the full property declaration syntax and you won't have to change any of the calling code.
The only real difference is that you'll have to use the property to get the value within your class, as the backing variable is generated and compile time and unavailable to your code.
FYI, simply typing "prop" (no quotes) triggers one of the snippets that comes with VS, and you just tab your way through, by far the quickest option.
Why aren't you doing:
public int SomeProperty { get; set; }
or
public int SomeOtherProperty { get; private set; }
?
from this line:
string mytest;
select the whole line "string mytest;",
then VS menu: Edit > Refactor > Encapsulate field ...
you get this:
public string Mytest { get => mytest; set => mytest = value; }
we can quickly create c# properties in visual studio using prop shortcut
and behalf of visual studio tool we can generate c# properties using a tool called c# property generator..
when class has so many properties in it , when we create a object of that class,
we have to take certain pain to assign properties so this tool will reduce your pain to certain extent this will automatically assign object with properties..
c# property assigner
You probably should be using Auto-Implemented properties in C# for most things. However, if you want 'old-style' properties with explicit backing fields you can create a Visual Studio code snippet to make them easier to write. This blog post has an example of one.
I found the following syntax as a VB.NET property and I'm trying to convert it to c#, but I'm not sure how to accomplish that.
Public Property SomeText(ByVal someEnumThing as SomeEnum) As String
Get
Select Case someEnumThing
//figure out what string to return
End Select
End Get
Set(ByVal Value as String)
Select Case someEnumThing
//figure out what string to set
End Select
End Set
End Property
I've never seen a property done like this before, any ideas?
I guess you're referring to the arguments for the property. Well, as far as I know, C# only supports them for indexers, which cannot have a name (e.g. this[SomeEnum someEnumThing] {}).
If you want to get a similar behavior, you can create a helper class with an indexer property and use it to expose the "name" of the property:
public class YourClass {
public struct SomeTextProperty {
private readonly YourClass owner;
internal SomeTextProperty(YourClass owner) {
this.owner = owner;
}
public string this[SomeEnum someEnumThing] {
get {
return owner.GetSomeText(someEnumThing);
}
set {
owner.SetSomeText(someEnumThing, value);
}
}
}
public SomeTextProperty SomeText {
get {
return new SomeTextProperty(this);
}
}
private string GetSomeText(SomeEnum someEnumThing) {
// implementation to get it
}
private void SetSomeText(SomeEnum someEnumThing, string value) {
// implementation to set it
}
}
Hmm... maybe the switch statement?
It is impossible to create a Property in C# which has arguments, unless it's the default property:
public double this[int index]
{
get {...}
set {...}
}
Just one of those areas where VB differs from C#.
It is not recommended to use syntax like this since you will not be able to use that property from a C# project that references this assembly.
If you're talking about the fact that the property is parameterized...
There's no direct translation for this in c# that I know of. Basically this is carryover from VB6 where you could make this weird quasi-collection property for a class. The easiest way to get similar functionality is to create a dictionary object and either publicly expose it or create an accessor. Where the VB code accesses this property like Class.SomeText("SomeKey") your C# code will become Class.SomeDictionaryProperty["SomeKey"]
Unfortunately this still isn't quite the same since the collection accessor won't be able to "see" the index value. This has been a minor source of frustration for me as well in the past coming from a VB background.
The Select Case will be a switch statement. Is that what you are specifically referring to?
EDIT: here's what I was referring to in my comment to #Lucero's answer to get close to the VB.NET syntax.
private SomeEnum SomeEnumThing { get; set; }
public string SomeText {
get {
switch (SomeEnumThing) {
//figure out what string to return
}
}
set {
switch (SomeEnumThing) {
//figure out what string to set
}
}
}
In C# do properties need to reference private member variables, or can I just declare the properties and use them directly in the class code?
If the former is the best practice, then does that rule out using C# property short-hand? I.e.
public string FirstName { get; set; }
Properties, when implemented like this:
public string FirstName { get; set; }
Automatically create a private member variable (the compiler does this for you), so you don't have to worry about it. This will behave exactly the same as if you do:
private string firstName;
public string FirstName {
get { return firstName; }
set { firstName = value; }
}
There is no reason not to use the automatic properties ( { get; set; } ). The provide the same advantages as making your own private member variable.
In addition, if you later decide you need to do extra processing (for example, if you decide to implement INotifyPropertyChanged in your property setter), you can add this without changing your public API, but putting a backing field in manually.
You don't need properties to access private fields but in general it is considered best practice.
And you can use auto-properties (short hand) untill you need to add more functionality to a property, like validation. Changing it to a 'real' property is always a non-breaking change.
Properties created like this
public String Caption{ get; set; }
this will be compiled as
[CompilerGenerated]
private string <Caption>k__BackingField;
public string Caption
{
[CompilerGenerated]
get
{
return this.<Caption>k__BackingField;
}
[CompilerGenerated]
set
{
this.<Caption>k__BackingField = value;
}
}
The above code is extracted after compilation using reflector tool.
They do not need to reference private member variables. You can use them directly in the class.
Properties do not need to reference private member variables. It is best practice, though, to have them do so. You can think of properties as methods if it makes it easier to understand. You can run code inside of them. You can return whatever you want. You can call methods and use private member variables. You can even simply return a constant.
I use private member variables in almost all cases. It allows me to create a readonly property, or to provide some rules to those outside my class of getting or setting properties that my class doesn't have to follow.
To add on to Reed's answer, inside of your code (within the class itself) the member functions should adhere to this and actually use the Property rather then the actual private member. For instance if you had this:
public string FirstName { get; set; }
And you had a strange method called public char GetFirstLetter() that returned the first letter in a person's first name you'd want to do it like this:
public char GetFirstLetter()
{
return FirstName[0];
}
Instead of actually using your private variable. When you set a property a programmer may have written code to set it in a particular manner. So it only makes sense to simply use that property within your class methods.
C# can reference private variables as in:
public class A
{
private string _b;
public string B
{
get { return _b; }
set { _b = value; }
}
}
The get;set; designation is automatic properties which when compiled will generate the private variable for you, as a way to make it easy to setup your code.
Using properties is the best way to provide a method of control and security to the attributes in a class, always keep the attributes private if possible.
if you use like
public string FirstName { get; set; }
compiler will automatically adds getters and setters for this property automatically.it not a bad practice.
Here is the proof
if you declare
private string firstName;
public string FirstName
{
get { return firstName; }
set { firstName = value; }
}
like this also compiler will takes it as
so its not ruled out... :)