Why do we use fields & properties instead of just a variable?

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What is the difference between a field and a property in C#?
Difference between Property and Field in C# .NET 3.5+

I have seen that in c# the following pattern is common:

   private string m_name = string.Empty;

public string Name
{
    get
    {
        return m_name;
    }
    set
    {
        m_name = value;
    }
}

why do we use a field and a property to hold a value when we can use a simple variable? why should I use fields and properties instead of a simple variable?

It depends on what you want to pre-process the value. Imagine if you (for some reason) wanted to make sure any string saved as Name contained at least 1 'e', you could do all the logic in the setter instead of in the main code body. — Ichabod Clay, Dec 05 '12 at 18:56

score 2 · Accepted Answer · answered Dec 05 '12 at 18:56

Just for encapsulation principle. For hinding concrete implementaiton, and plus, you have an opportunity (in this case) to add additional code inside get/set.

If you don't need addittional code, you can use just

public string Name{get;set;}

or use fileds, as you would like. But using properties is a guideline offered by Microsoft.

So basically all, follow it.

score 0 · Answer 2 · answered Dec 05 '12 at 18:56

There are a lot of reasons for this, but 2 come to mind right away:

First, a property can be easily bound to a control or other reflection-based controls that read all properties (rather than fields).

Second, there may be actions that you want to perform in getters or setters (such as firing a NotifyPropertyChanged event).

score 0 · Answer 3 · answered Dec 05 '12 at 18:57

Properties provide the opportunity to protect a field in a class by reading and writing to it through the property. In other languages, this is often accomplished by programs implementing specialized getter and setter methods. C# properties enable this type of protection while also letting you access the property just like it was a field.

Another benefit of properties over fields is that you can change their internal implementation over time. With a public field, the underlying data type must always be the same because calling code depends on the field being the same. However, with a property, you can change the implementation.

Why do we use fields & properties instead of just a variable?

3 Answers3