问题
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?
回答1:
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.
回答2:
Sku is an int, can't be defaulted to string "sku". Please check Optional URI Parameters and Default Values
回答3:
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)
{ ... }
来源：https://stackoverflow.com/questions/38249019/web-api-optional-parameters