Optional parameter declaration and default values

[Imran Aziz]

Hello All,
I am new to C# , how can I delare parameters to a function as optional,
and also how are default values assigned ?

consider the function

public String myFunc(String thisisOptional, String OptWithDefaultValue)
{

}

Imran.

 

[Mark Rae]

I am new to C# , how can I delare parameters to a function as optional,

You don't - you use overloads.

public string myFunc()
{
/*
do something
*/
}

public string myFunc(string thisisOptional)
{
/*
do something with thisisOptional
*/
string newString = myFunc();
}

 

[Imran Aziz]

I see, it means there is no way to declare optional function parameters in
C#, strange , no doubt I was not able to find it in the documentation

Thanks a lot.

Imran.

 

[Octavio Hernandez]

Hi,

In this video Anders Hejlsberg, the designer of C#, explains why they
decided to leave optional parameters out of C#:

http://msdn.microsoft.com/msdntv/episode.aspx?xml=episodes/en/20040624csharpah/manifest.xml

Regards - Octavio

 

[Mark Rae]

it means there is no way to declare optional function parameters in C#
Correct.

strange

Nope - entirely by design.

 

[Franco, Gustavo]

You can't.

Use:
1) Overloads
public String myFunc()
{
myFunc(null, x //default value);
}

public String myFunc(String thisisOptional)
{
myFunc(thisisOptional, x //default value);
}

public String myFunc(String thisisOptional, String OptWithDefaultValue)
{
..... code here.
}

2) params object[] parameters like parameter in the method.

public String myFunc(params string[] parameters )
{
String thisisOptional = null;
String OptWithDefaultValue = defaultValue;

if (params.Lenght >= 2)
{
thisisOptional = parameters[0];
OptWithDefaultValue = parameters[1];
}
else if (params.Lenght == 1)
thisisOptional = parameters[0];

.... code here
}

Gustavo