Update Application to accept a TKey generic parameter

src/OpenIddict.EF/OpenIddictContext.cs

@@ -13,7 +13,7 @@ using OpenIddict.Models;
 namespace OpenIddict {
     public class OpenIddictContext<TUser, TApplication, TRole, TKey> : IdentityDbContext<TUser, TRole, TKey>
         where TUser : IdentityUser<TKey>
-        where TApplication : Application
+        where TApplication : Application<TKey>
         where TRole : IdentityRole<TKey>
         where TKey : IEquatable<TKey> {
         public OpenIddictContext() { }

src/OpenIddict.EF/OpenIddictStore.cs

@@ -1,4 +1,5 @@
 using System;
+using System.ComponentModel;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
@@ -8,7 +9,7 @@ using OpenIddict.Models;
 namespace OpenIddict {
     public class OpenIddictStore<TUser, TApplication, TContext, TKey> : IOpenIddictStore<TUser, TApplication>
         where TUser : IdentityUser<TKey>
-        where TApplication : Application
+        where TApplication : Application<TKey>
         where TContext : DbContext
         where TKey : IEquatable<TKey> {
         public OpenIddictStore(TContext context) {
@@ -25,7 +26,9 @@ namespace OpenIddict {
         }
 
         public virtual Task<TApplication> FindApplicationByIdAsync(string identifier, CancellationToken cancellationToken) {
-            return Applications.SingleOrDefaultAsync(application => application.Id == identifier, cancellationToken);
+            var key = (TKey) TypeDescriptor.GetConverter(typeof(TKey)).ConvertFromInvariantString(identifier);
+
+            return Applications.SingleOrDefaultAsync(application => application.Id.Equals(key), cancellationToken);
         }
 
         public virtual Task<TApplication> FindApplicationByLogoutRedirectUri(string url, CancellationToken cancellationToken) {

src/OpenIddict.Models/Application.cs

@@ -4,9 +4,13 @@
  * the license and the contributors participating to this project.
  */
 
+using System;
+
 namespace OpenIddict.Models {
-    public class Application {
+    public class Application : Application<string> { }
-        public string Id { get; set; }
+
+    public class Application<TKey> where TKey : IEquatable<TKey> {
+        public TKey Id { get; set; }
         public string DisplayName { get; set; }
         public string RedirectUri { get; set; }
         public string LogoutRedirectUri { get; set; }

src/OpenIddict/OpenIddictExtensions.cs

@@ -23,7 +23,7 @@ namespace Microsoft.AspNetCore.Builder {
         }
 
         public static IdentityBuilder AddOpenIddict<TApplication>([NotNull] this IdentityBuilder builder)
-            where TApplication : Application {
+            where TApplication : class {
             if (builder == null) {
                 throw new ArgumentNullException(nameof(builder));
             }