Help - Creating a function to deal with null parameters

[pjarvis]

Hi guys,

Say for example i have a hypothetical function taking 4 parameters such as the one below:

public void InsertRow(char gender, double decimalAge, double height, double weight)
{
//Adds data into a MySQL database
}

If i have a piece of data missing such as height, but i still want to call the function that will add the other parameters into the database, how would i do it? I'd like to pass
a 'null' to the function, is there any way of achieving this without getting compiler errors?

Thanks in advance

Paul

 

[cristalink]

In .NET 2.0, you can use

public void InsertRow(char? gender, double? decimalAge, double? height,
double? weight)
{
if( gender == null )
{
//not provider
}
else
{
field = (char) gender;
}
....

 

[Jon Skeet [C# MVP]]

Say for example i have a hypothetical function taking 4 parameters
such as the one below:

public void InsertRow(char gender, double decimalAge, double height, double weight)
{
//Adds data into a MySQL database
}

If i have a piece of data missing such as height, but i still want to
call the function that will add the other parameters into the
database, how would i do it? I'd like to pass
a 'null' to the function, is there any way of achieving this without
getting compiler errors?

Well, char and double values can't be null. You options are:
1) On .NET 2.0, use nullable types: char? and double?
See http://pobox.com/~skeet/csharp/csharp2/nullable.html for more on
this

2) Otherwise, have particular char and double values that you wouldn't
normally actually use, and have those be "special" ways of representing
null. It's a bit hacky, admittedly...