Dart - this keyword

this keyword represents an implicit object pointing to the current class object. It refers to the current instance of the class in a method or constructor. The this keyword is mainly used to eliminate the ambiguity between class attributes and parameters with the same name. When the class attributes and the parameter names are the same, this keyword is used to avoid ambiguity by prefixing class attributes with this keyword. this keyword can be used to refer to any member of the current object from within an instance method or a constructor.

Uses of this Keyword

• It can be used to refer to the instance variable of the current class.
• It can be used to make or initiate a current class constructor.
• It can be passed as an argument in the method call.
• It can be passed as an argument in the constructor call.
• It can be used to make a current class method.
• It can be used to return the current class Instance.

Referring to Instance Variables

Example :

// Dart program to illustrate
// this keyword
void main() {
    Student s1 = new Student('S001');
}

class Student {
    // defining local st_id variable
    var st_id;
    Student(var st_id) {
        // using this keyword
        this.st_id = st_id;
        print("GFG - Dart THIS Example");
        print("The Student ID is : ${st_id}");
    }
}

Output:

GFG - Dart THIS Example
The Student ID is : S001

Returning the Current Class Instance

Example :

// Dart program to illustrate
// this keyword
void main() {
    mob m1 = new mob();
    m1.Car("M101");
}

class mob {
    String mobile = "";
    Car(String mobile) {
        // use of this keyword
        this.mobile = mobile;
        print("The mobile is : ${mobile}");
    }
}

Output:

The mobile is : M101

Conclusion

The this keyword in Dart is a powerful tool that provides clear and unambiguous access to class members. It enhances code readability, enables constructor chaining, and allows method calls within the same instance. By utilizing this, developers can write cleaner and more efficient Dart programs.