What is "this" in object constructors?

[mrjohn]

Hullo, I've been learning C# and I had a question. I'm creating a class, and I was writing the constructor. When I was assigning values to it's variables, I found that the compiler seems to take it both with and without the "this" keyword. Does it make a difference whether I use it or not?

[CODE=C#]public class Car
{
private float weight, gasTank;
public Car(float myWeight, float myGasTank)
{
this.weight = myWeight;
this.gasTank = myGasTank;
}[/CODE]

[tlhintoq]

Nope. No difference. this. is merely specifying the scope.

In theory you could have a "weight" in one class, and a "weight" in another class. You would want to be clear about which one you mean.

class1.weight
class2.weight

In this case when the search starts to find a 'weight' the only one is the one in .this

[mrjohn]

Cool beans. Thanks.

[artov]

It is quite common to use same name for object's instances and parameters in constructors, like

public class Appointment
{
   float duration;
   string name;
   DateTime time;

   public Appointment(string name, DateTime time, float duration)
   {
      this.name = name;
      this.time = time;
      this.duration = duration;
   }
..
}

This make the code easier to read and if you use environment like Visual Studio or SharpDevelop, it is easier to select the right constructor, if there are several.