Variables in C# and VFP
C#
public, private
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VFP
Local, Private, Public
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C# Syntax Notes
C# is strongly typed and every variable must be defined as being of a known type
before it can be used. It is also more strongly object-oriented than Visual FoxPro and
doesn't have variables existing independently of classes and objects. A private variable
which exists inside an object will typically be exposed as a public property with code
like this:
class Customer
{
private string cust_id;
private string company;
public string Cust_id
{
get
{ return cust_id; }
set
{ cust_id = value; }
}
public string Company
{
get
{ return company; }
set
{ company = value; }
}
}
This is the simplest of examples. In reality, both the getter and setter methods might
process the data or restrict access to their values.
Note that the private variable "cust_id" and the public property "Cust_id" have different
capitalisation and refer to two different things. C# is case-sensitive.
VFP Syntax Notes
Visual FoxPro has none of this protection. All variables are of the same
general type and you can even change the type of data stored in a variable
after it has been used. If you assign a value to a variable without having
declared it then that variable will immediately be created and be given
Private scope.
Variable scope
Both languages apply scope to variables. Visual FoxPro has a simple system of
scope:
-
Public variables are visible throughout the application.
-
Private variables are visible in every module called from the one
in which they are declared.
-
Local variables are visible in the module in which they are declared.
FoxPro supports object-oriented and procedural code so the term 'module'
above might be a program, procedure, function or method.
Constants
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