Ninject 2.1 ActivationException : Error activating string
I am confused about why I am receiving "Ninject.ActivationException : Error Activating string No matching bindings are available, and the type is not self-bindable" in random bindings. If I leave the binding for IMedia in place it will throw the ActivationException, but if I use the CallbackProvider it works. All of these classes are structured the same with a few different properties. I'm confused as to why ILocationType, IMedia, and IFarmDataContext throw ActivationException while the others do not. Any ideas?
/******************************
* Core Types
******************************/
Bind<IFarmDataContext>().ToProvider(new CallbackProvider<IFarmDataContext>(delegate { return new FarmDataContext(); }));
//Media
Bind<IMedia>().To<Media>(); //blows up
//Bind<IMedia>().ToProvider(new CallbackProvider<IMedia>(delegate { return new Media(); }));
Bind<IMediaType>().To<MediaType>();
Bind<IMediaRelated>().To<MediaRelated>();
//Location
Bind<ILocation>().To<Location>();
Bind<ILocationType>().ToProvider(new CallbackProvider<ILocationType>(delegate { return new LocationType(); }));
Bind<ILocationDetail>().To<LocationDetail>();
Ninject doesn't have a binding for the "String key" to inject in the Media .ctor; When it tries to create a type that depends on Media, it doesn't know how to resolve the dependency and throws. For most types, Ninject would try to create something for you, but string and value types are not self-bindable as we don't have a good default value for them and it can cause havoc on types that use different conventions with primitives.
You need add a parameter value in your bindings (.WithContructorArgument("key", someValue)) or use some kind of provider (which you have done).
Below are the IMedia interface and Media implementation. Media is a partial class with the primary class generated via a LinqToSql DBML file. This is the case for all of the types listed above in the list of bindings.
public interface IMedia : IValidationDictionary, IBaseDescriptor {
/// <summary>
/// Returns a specific Media object specifying
/// if you want the full or lite version
/// </summary>
/// <param name="id"></param>
/// <param name="isLite"></param>
/// <param name="context"></param>
/// <returns></returns>
IMedia Get(long id, bool isLite, DataContext context);
/// <summary>
/// Returns the lite version of the request Media object
/// </summary>
/// <param name="id"></param>
/// <param name="context"></param>
/// <returns></returns>
IMedia Get(long id, DataContext context);
/// <summary>
/// Returns a list of Media Objects
/// </summary>
/// <param name="isLite"></param>
/// <param name="context"></param>
/// <returns></returns>
ValidationList<IMedia> List(bool isLite, DataContext context);
/// <summary>
/// Returns a list of Media Objects with pagination capabilities
/// </summary>
/// <param name="isLite"></param>
/// <param name="skip"></param>
/// <param name="top"></param>
/// <param name="context"></param>
/// <returns></returns>
ValidationList<IMedia> List(bool isLite, int skip, int top, DataContext context);
}
public partial class Media : BaseDescriptor, IMedia {
#region Constructors
public Media(String key, IError error)
: base() {
AddError(key, error);
}
#endregion
#region Properties
public MediaType Type {
set { if (TypeID <= 0) { MediaType = value; } }
get { return MediaType; }
}
#endregion
#region Internal Methods
/// <summary>
/// Truncates relationships as appropriate to reduce over-the-wire size
/// </summary>
protected override void MakeLite() {
MediaRelateds = new EntitySet<MediaRelated>();
}
/// <summary>
/// Validates the values and returns true if there are no problems.
/// </summary>
override public bool Validate() {
this.ClearErrors();
if (this.TypeID <= 0) { this.AddError("TypeID", new Error(ErrorType.VALIDATION, "TypeID is missing or invalid")); }
if (string.IsNullOrEmpty(this.Path)) { this.AddError("Path", new Error(ErrorType.VALIDATION, "Path is missing or invalid")); }
if (this.CreatedOn.Year <= 1900) { this.AddError("CreatedOn", new Error(ErrorType.VALIDATION, "CreatedOn is missing or invalid")); }
if (this.CreatedBy <= 0) { this.AddError("CreatedBy", new Error(ErrorType.VALIDATION, "CreatedBy is missing or invalid")); }
if (this.UpdatedOn.Year <= 1900) { this.AddError("UpdatedOn", new Error(ErrorType.VALIDATION, "UpdatedOn is missing or invalid")); }
if (this.UpdatedBy <= 0) { this.AddError("UpdatedBy", new Error(ErrorType.VALIDATION, "UpdatedBy is missing or invalid")); }
if (!string.IsNullOrEmpty(this.Path) && this.Path.Length > 255) { this.AddError("Path", new Error(ErrorType.VALIDATION, "Path is longer than the maximum of 255 characters")); }
return (this.ErrorCount == 0);
}
#endregion
#region Public Methods
public ValidationList<IMedia> List(bool isLite, DataContext context) {
return List(isLite, 0, 0, context);
}
public ValidationList<IMedia> List(bool isLite, int skip, int top, DataContext context) {
if (context == null) { context = new DataContext(); }
var query = context.Medias.Where(x => x.DeletedOn == null);
List<Media> results;
if (skip > 0 || top > 0) {
if (top > 0) {
if (skip < 0) { skip = 0; }
results = query.OrderBy(x => x.ID).Skip(skip).Take(top).ToList();
} else {
results = query.OrderBy(x => x.ID).Skip(skip).ToList();
}
} else {
results = query.OrderBy(x => x.ID).ToList();
}
var finalResult = new ValidationList<IMedia>(new List<IMedia>());
foreach (var result in results) {
result.IsLite = isLite;
finalResult.Source.Add(result);
}
return finalResult;
}
public IMedia Get(long id, DataContext context) {
return Get(id, false, context);
}
public IMedia Get(long id, bool isLite, DataContext context) {
if (context == null) { context = new DataContext(); }
var results = context.Medias.Where(x => x.ID == id && x.DeletedOn == null).ToList();
var result = (results.Count > 0 ? results[0] : null);
if (result != null) {
result.IsLite = isLite;
}
return result;
}
#endregion
}