以下是源代码：

注意红色部分，为什么用GrossSales和CommissionRate，而不是grossSales和commissionRate  ？？

抑或是两种方法相同？？

public class CommissionEmployee : object

{
private string firstName;
private string lastName;
private string socialSecurityNumber;
private decimal grossSales; // gross weekly sales
private decimal commissionRate; // commission percentage

// five-parameter constructor
public CommissionEmployee( string first, string last, string ssn,
decimal sales, decimal rate )
{
// implicit call to object constructor occurs here
firstName = first;
lastName = last;
socialSecurityNumber = ssn;
GrossSales = sales; // validate gross sales via property
CommissionRate = rate; // validate commission rate via property
} // end five-parameter CommissionEmployee constructor

// read-only property that gets commission employee's first name
public string FirstName
{
get
{
return firstName;
} // end get
} // end property FirstName

// read-only property that gets commission employee's last name
public string LastName
{
get
{
return lastName;
} // end get
} // end property LastName

// read-only property that gets
// commission employee's social security number
public string SocialSecurityNumber
{
get
{
return socialSecurityNumber;
} // end get
} // end property SocialSecurityNumber

// property that gets and sets commission employee's gross sales
public decimal GrossSales
{
get
{
return grossSales;
} // end get
set
{
grossSales = ( value < 0 ) ? 0 : value;
} // end set
} // end property GrossSales

// property that gets and sets commission employee's commission rate
public decimal CommissionRate
{
get
{
return commissionRate;
} // end get
set
{
commissionRate = ( value > 0 && value < 1 ) ? value : 0;
} // end set
} // end property CommissionRate

// calculate commission employee's pay
public decimal Earnings()
{
return commissionRate * grossSales;
} // end method Earnings

// return string representation of CommissionEmployee object
public override string ToString()
{
return string.Format(
"{0}: {1} {2}\n{3}: {4}\n{5}: {6:C}\n{7}: {8:F2}",
"commission employee", FirstName, LastName,
"social security number", SocialSecurityNumber,
"gross sales", GrossSales, "commission rate", CommissionRate );
} // end method ToString
} // end class CommissionEmployee