Web API optional parameters
I have a controller with the following signature:
[Route("products/filter/{apc=apc}/{xpc=xpc}/{sku=sku}")]
public IHttpActionResult Get(string apc, string xpc, int? sku)
{ ... }
I call this method with following URIs:
~/api/products/filter?apc=AA&xpc=BB
~/api/products/filter?sku=7199123
The first URI works without issue. The second one has a strange side effect. Even though the default values for apc and xpc should be null when not provided, the parameters are actually their names. I can overcome this by adding the additional logic:
apc = (apc == "apc") ? null : apc;
xpc = (xpc == "xpc") ? null : xpc;
This seems like a hack, and would be problematic if value passed was ever equal to the parameter name.
Is there a way to define the Route without this side effect?
null?
I figured it out. I was using a bad example I found in the past of how to map query string to the method parameters.
In case anyone else needs it, in order to have optional parameters in a query string such as:
~/api/products/filter?apc=AA&xpc=BB
~/api/products/filter?sku=7199123
you would use:
[Route("products/filter/{apc?}/{xpc?}/{sku?}")]
public IHttpActionResult Get(string apc = null, string xpc = null, int? sku = null)
{ ... }
It seems odd to have to define default values for the method parameters when these types already have a default.
you need only set default value to parameters(you do not need the Route attribute):
public IHttpActionResult Get(string apc = null, string xpc = null, int? sku = null)
{ ... }
Sku is an int, can't be defaulted to string "sku". Please check Optional URI Parameters and Default Values.
int if it is not null. If you stick to int? the framework provides the validation out-of-the-box and you only need to check the ModelState...
[Route("~/api/[Controller]/AutocompleteAdress/{input=}/{input2=}")]
public IEnumerable<string> GetAutocompleteAdress(string input, string input2)
It works for me (ASP.NET WEB API).
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It seems odd to have to define default values for the method parameters when these types already have a default.. Checked the details on MSDN als here but it doesn't talk about any technical details as to why it has been decided to be like that.int?marks it as nullable, but it is not optional: You must pass either a non-null integral value ornull. Adding= null, however, is the syntax required for declaring the default value of an optional parameter. Hence,int? sku = nullis a nullableintwhose default value isnull(instead of some other integral value).