C# Best Practices - Specify Clear Method Parameters
Improve parameters
parameter order
public OperationResult PlaceOrder(Product product, int quantity, bool includeAddress, bool sendCopy)
Acted opon or key to the operation (like product)
Required for the operation
Flags (like inclludeAddress)
Optional parameters
Best Practices
Do:
Define coherent parameters names
Defind an XML document comment for each parameter
Keep the number of parameters to a minimum
Order the parameters in a logical sequence
Use a consistent parameter order
Avoid:
Unused parameters
Named arguments
public OperationResult PlaceOrder(Product product, int quantity, bool includeAddress, bool sendCopy) var result = Vendor.PlaceOrder(product, quantity:12, includeAddress:true, sendCopy:false);
Named arguments Best Practices
Do:
Use named arguments as needed for clarity when calling a method
Avoid:
Unnecessary named arguments (PlaceOrder(product:product...))
Optional Parameters
public OpertionalResult PlaceOrder(Product product, int quantity, DateTimeOffset? deliverBy = null, string instructions = "standard delivery")
Features:
Specify a default vallue
Are optional when the method is called
If argument is not provided, default is used
Can dramatically reduce the number of overloads
Notes:
Optional parameters must be defined after required parameters
When calling the method, if an argument is provided for any optional parameter, it must also provide arguments for all preceding parameters, or use named arguments.
Best Practices
Do:
Use optional parameters to minimize overload bloat
Avoid:
Optional parameters when the parameters are one or the other
Optional parameters if default could change and component versioning is important
Ref & Out
By Value or By Reference
public bool PlaceOrder(Product product, int quantity, ref string orderText) public bool PlaceOrder(Product product, int quantity, out string orderText)
ref
Argument passed "by reference"
Argument variable must be initialized
Parameter values can be changed in the method
Changes are reflecting in the calling code
out
Argument passed "by reference"
Argument variable must be declared
Parameter values must be set in the method
Changes are reflecting in the calling code
Best Practices
Do:
Use ref when the method expects an incoming value
Use out when the method expects no incoming value
Avoid:
ref and out where feasible, return an object instead
FAQ
1.What is a named argument and when should it be used?
A named argument uses the parameter name when calling the method
Used to clarify the purpose of an argument and define arguments without concern for there position in the parameter list
2.How is an optional parameter defined?
By sepecify a default value
3.What is difference between passing an argument by value vs by reference?
When passed by value (which is default), the value of the argement is passed to the method.
When passed by reference (use ref or out), the variable is effectively passed to the method.
Because of this, passing by reference enables the method to change the value of the parameter and have that changed reflected in the calling code.
4.What is the difference between ref and out?
A ref parameter requires that the argument be initialized before it is passed.The method can modify the value for the ref parameter.
A out parameter must be declared,but not initialized before it is passed.The method must provide a value for the out parameter.