Override .Tostring Method C#

Override .ToString method c#

You are returning a string that just says the phrase _name + _number + _date + _salary.

What you likely wanted to do is build a string using those fields. If you wanted them all mushed together Concat would work, but it would be highly un-readable

public override string ToString()
{
    return String.Concat(_name, _number, _date, _salary);
}

However what would be better is to use Format and include labels with the values

public override string ToString()
{
    return String.Format("Name:{0}, Number:{1}, Date:{2}, Salary:{3}",_name, _number, _date, _salary);
}

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If you are using C# 6 or newer you can use the following cleaner format

public override string ToString()
{
    return $"Name:{_name}, Number:{_number}, Date:{_date}, Salary:{_salary}";
}

Which is the exact same logic as the previous String.Format version.

How can I override ToString() method for all IEnumerableInt32?

How can I achieve this so that my ToString() implementation is called when I call .ToString() on List for example?

You can't, basically. Extension methods are only used if no matching instance method can be found.

I suggest you give your method a different name, avoiding the problem - and the potential confusion your method would cause.

Note that even if extension methods were matched in preference to (say) methods declared on object, it would only make a difference for your own code being compiled with an appropriate using directive - not any other code which has already bound the call to the normal one.

If you can give more information about what you're trying to achieve, we may be able to help you more - but for the moment, something like ToDelimitedString (or whatever your method does) sounds like the best bet to me.

override ToString() with override and new keyword

It makes a difference when you do this:

object a = new A(); // notice the type of the variable here!
object b = new B();
Console.WriteLine(a.ToString());
Console.WriteLine(b.ToString());

a.ToString() will not call your implementation of ToString and will instead call object.ToString, which returns the fully qualified type name of the object. b.ToString() will call your implementation.

What you did in B is called overriding. What you did in A is called hiding. Hiding loses its effect when the compile time type of a variable is not that type anymore. Your implementation of ToString will only be called when the compile time type is A.

Learn more here.

How can I override the ToString() method in C#?

As per your question, to change some characters in the ToString implementation, you need to call the existing ToString method by using the base keyword:

public override string ToString()
{
    return base.ToString().Replace("something", "another thing");
}

Note that if you forget the base keyword it will call itself repeatedly until you get a StackOverflowException.

2 override ToString() methods across multiple classes

It's returning Item.ToString() because you're calling it when you do stuff += items.ToString();.

Instead, just do:

string stuff = "Items: ";

for (int i = 0; i < list.Count; i++)
{
    Item items = list[i];
    stuff += items.Name + ", ";
}

// Remove the last comma
stuff = stuff.Substring(0, s.LastIndexOf(", "));
return name + stuff;

If we don't remove the last comma, we get this:

"Items: Ipod, Motorolla, Samsung, Nokia, "

Instead of:

"Items: Ipod, Motorolla, Samsung, Nokia"

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