Get application name's default value from the entrance assembly

framework/src/Volo.Abp.Core/Microsoft/Extensions/DependencyInjection/ServiceCollectionConfigurationExtensions.cs

@@ -1,6 +1,8 @@
-using Microsoft.Extensions.Configuration;
+using JetBrains.Annotations;
+using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection.Extensions;
 using Microsoft.Extensions.Hosting;
+using Volo.Abp;
 
 namespace Microsoft.Extensions.DependencyInjection;
 
@@ -11,7 +13,15 @@ public static class ServiceCollectionConfigurationExtensions
         return services.Replace(ServiceDescriptor.Singleton<IConfiguration>(configuration));
     }
 
+    [NotNull]
     public static IConfiguration GetConfiguration(this IServiceCollection services)
+    {
+        return services.GetConfigurationOrNull() ?? 
+               throw new AbpException("Could not find an implementation of " + typeof(IConfiguration).AssemblyQualifiedName + " in the service collection.");
+    }
+    
+    [CanBeNull]
+    public static IConfiguration GetConfigurationOrNull(this IServiceCollection services)
     {
         var hostBuilderContext = services.GetSingletonInstanceOrNull<HostBuilderContext>();
         if (hostBuilderContext?.Configuration != null)
@@ -19,6 +29,6 @@ public static class ServiceCollectionConfigurationExtensions
             return hostBuilderContext.Configuration as IConfigurationRoot;
         }
 
-        return services.GetSingletonInstance<IConfiguration>();
+        return services.GetSingletonInstanceOrNull<IConfiguration>();
     }
 }

framework/src/Volo.Abp.Core/Volo/Abp/AbpApplicationBase.cs

@@ -44,7 +44,7 @@ public abstract class AbpApplicationBase : IAbpApplication
         var options = new AbpApplicationCreationOptions(services);
         optionsAction?.Invoke(options);
         
-        ApplicationName = options.ApplicationName;
+        ApplicationName = GetApplicationName(options);
 
         services.AddSingleton<IAbpApplication>(this);
         services.AddSingleton<IApplicationNameAccessor>(this);
@@ -312,4 +312,30 @@ public abstract class AbpApplicationBase : IAbpApplication
 
         _configuredServices = true;
     }
+    
+    private static string GetApplicationName(AbpApplicationCreationOptions options)
+    {
+        if (!string.IsNullOrWhiteSpace(options.ApplicationName))
+        {
+            return options.ApplicationName;
+        }
+
+        var configuration = options.Services.GetConfigurationOrNull();
+        if (configuration != null)
+        {
+            var appNameConfig = configuration["ApplicationName"];
+            if (string.IsNullOrWhiteSpace(appNameConfig))
+            {
+                return appNameConfig;
+            }
+        }
+        
+        var entryAssembly = Assembly.GetEntryAssembly();
+        if (entryAssembly != null)
+        {
+            return entryAssembly.GetName().Name;
+        }
+
+        return null;
+    }
 }

framework/src/Volo.Abp.Core/Volo/Abp/IApplicationNameAccessor.cs

@@ -1,3 +1,5 @@
+using JetBrains.Annotations;
+
 namespace Volo.Abp;
 
 public interface IApplicationNameAccessor
@@ -7,5 +9,6 @@ public interface IApplicationNameAccessor
     /// This is useful for systems with multiple applications, to distinguish
     /// resources of the applications located together.
     /// </summary>
+    [CanBeNull]
     string ApplicationName { get; }
 }