Question

Currently I am calling all data queries as showed on BreezeJs docs / examples:

getEntityList = function (predicate) {
  var query = new entityModel.EntityQuery().from("EntityList");
  if (predicate)
    query = query.where(predicate);
  return manager.executeQuery(query);
}

But I want to pass additional parameter to controller action before any queryable result is returned:

[AcceptVerbs("GET")]
public IQueryable<Entity> EntityList(string actionParam) {
  //here goes logic that depends on actionParam
  //and returns IQueryable<Entity>
}

As we know from documentation:

Breeze converts the query into an OData query string such as this one:

?$filter=IsArchived%20eq%20false&$orderby=CreatedAt

This is where the problem starts. How should I build query to pass param to controller action?

getEntityList = function (predicate, actionParam) {
  var query = new entityModel.EntityQuery().from("EntityList");
  if (predicate)
    query = query.where(predicate);
  if(actionParam)
    // ???
  return manager.executeQuery(query);
}

I already tried setting route to:

routes.MapHttpRoute(
            name: "DefaultApi",
            routeTemplate: "api/{controller}/{action}/{actionParam}",
            defaults: new { query = RouteParameter.Optional }
        );

and sending actionParam by applying it in a from section,

var query = new entityModel.EntityQuery()
  .from("EntityList/" + encodeURIComponent(actionParam));

but encoding fails on some special chars and bad request is being thrown.

How can I properly send actionParam in such scenario? Please help.

Answer 1

As of v 0.76.1, you can use the EntityQuery.withParameters method to pass additional parameters to any service method. So you can now construct a query like the following that both passes parameters and uses breeze’s IQueryable support.

EntityQuery.from("EmployeesFilteredByCountryAndBirthdate")
                 .withParameters({ BirthDate: "1/1/1960", Country: "USA" })
                 .where("LastName", "startsWith", "S")
                 .orderBy("BirthDate");

where your controller method would look something like this:

[HttpGet]
public IQueryable<Employee> EmployeesFilteredByCountryAndBirthdate(DateTime birthDate, string country) {
      return ContextProvider.Context.Employees.Where(emp => emp.BirthDate >= birthDate && emp.Country == country);
}

The API docs have more information.