WithProperty by expression

src/Autofac/RegistrationExtensions.cs

@@ -882,6 +882,35 @@ private static Type[] GetImplementedInterfaces(Type type)
             return registration.WithProperty(new NamedPropertyParameter(propertyName, propertyValue));
         }
 
+        /// <summary>
+        /// Configure an explicit value for a property.
+        /// </summary>
+        /// <typeparam name="TLimit">Registration limit type.</typeparam>
+        /// <typeparam name="TReflectionActivatorData">Activator data type.</typeparam>
+        /// <typeparam name="TStyle">Registration style.</typeparam>
+        /// <typeparam name="TProperty">Type of the property being assigned.</typeparam>
+        /// <param name="registration">Registration to set property on.</param>
+        /// <param name="propertyExpression">Expression of a property on the target type.</param>
+        /// <param name="propertyValue">Value to supply to the property.</param>
+        /// <returns>A registration builder allowing further configuration of the component.</returns>
+        public static IRegistrationBuilder<TLimit, TReflectionActivatorData, TStyle>
+            WithProperty<TLimit, TReflectionActivatorData, TStyle, TProperty>(
+                this IRegistrationBuilder<TLimit, TReflectionActivatorData, TStyle> registration,
+                Expression<Func<TLimit, TProperty>> propertyExpression,
+                TProperty propertyValue)
+            where TReflectionActivatorData : ReflectionActivatorData
+        {
+            if (registration == null) throw new ArgumentNullException(nameof(registration));
+            if (propertyExpression == null) throw new ArgumentNullException(nameof(propertyExpression));
+            if (propertyValue == null) throw new ArgumentNullException(nameof(propertyValue));
+
+            var propertyInfo = (propertyExpression.Body as MemberExpression)?.Member as PropertyInfo;
+            if (propertyInfo == null)
+                throw new ArgumentOutOfRangeException(nameof(propertyExpression), RegistrationExtensionsResources.ExpressionDoesNotReferToProperty);
+
+            return registration.WithProperty(new NamedPropertyParameter(propertyInfo.Name, propertyValue));
+        }
+
         /// <summary>
         /// Configure an explicit value for a property.
         /// </summary>

src/Autofac/RegistrationExtensionsResources.resx

@@ -1,17 +1,17 @@
 <?xml version="1.0" encoding="utf-8"?>
 <root>
-  <!-- 
-    Microsoft ResX Schema 
-    
+  <!--
+    Microsoft ResX Schema
+
     Version 2.0
-    
-    The primary goals of this format is to allow a simple XML format 
-    that is mostly human readable. The generation and parsing of the 
-    various data types are done through the TypeConverter classes 
+
+    The primary goals of this format is to allow a simple XML format
+    that is mostly human readable. The generation and parsing of the
+    various data types are done through the TypeConverter classes
     associated with the data types.
-    
+
     Example:
-    
+
     ... ado.net/XML headers & schema ...
     <resheader name="resmimetype">text/microsoft-resx</resheader>
     <resheader name="version">2.0</resheader>
@@ -26,36 +26,36 @@
         <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
         <comment>This is a comment</comment>
     </data>
-                
-    There are any number of "resheader" rows that contain simple 
+
+    There are any number of "resheader" rows that contain simple
     name/value pairs.
-    
-    Each data row contains a name, and value. The row also contains a 
-    type or mimetype. Type corresponds to a .NET class that support 
-    text/value conversion through the TypeConverter architecture. 
-    Classes that don't support this are serialized and stored with the 
+
+    Each data row contains a name, and value. The row also contains a
+    type or mimetype. Type corresponds to a .NET class that support
+    text/value conversion through the TypeConverter architecture.
+    Classes that don't support this are serialized and stored with the
     mimetype set.
-    
-    The mimetype is used for serialized objects, and tells the 
-    ResXResourceReader how to depersist the object. This is currently not 
+
+    The mimetype is used for serialized objects, and tells the
+    ResXResourceReader how to depersist the object. This is currently not
     extensible. For a given mimetype the value must be set accordingly:
-    
-    Note - application/x-microsoft.net.object.binary.base64 is the format 
-    that the ResXResourceWriter will generate, however the reader can 
+
+    Note - application/x-microsoft.net.object.binary.base64 is the format
+    that the ResXResourceWriter will generate, however the reader can
     read any of the formats listed below.
-    
+
     mimetype: application/x-microsoft.net.object.binary.base64
-    value   : The object must be serialized with 
+    value   : The object must be serialized with
             : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
             : and then encoded with base64 encoding.
-    
+
     mimetype: application/x-microsoft.net.object.soap.base64
-    value   : The object must be serialized with 
+    value   : The object must be serialized with
             : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
             : and then encoded with base64 encoding.
 
     mimetype: application/x-microsoft.net.object.bytearray.base64
-    value   : The object must be serialized into a byte array 
+    value   : The object must be serialized into a byte array
             : using a System.ComponentModel.TypeConverter
             : and then encoded with base64 encoding.
     -->
@@ -135,4 +135,7 @@
   <data name="OnlyIfRequiresCallbackContainer" xml:space="preserve">
     <value>You can only attach a registration predicate to a registration that has a callback container attached (e.g., one that was made with a standard ContainerBuilder extension method).</value>
   </data>
-</root>
+  <data name="ExpressionDoesNotReferToProperty" xml:space="preserve">
+    <value>Expression does not refer to a property</value>
+  </data>
+</root>

test/Autofac.Test/ResolutionExtensionsTests.cs

@@ -1,7 +1,9 @@
-using Autofac.Core;
+using System;
+using Autofac.Core;
 using Autofac.Core.Activators.ProvidedInstance;
 using Autofac.Core.Registration;
 using Autofac.Test.Scenarios.Parameterisation;
+using Autofac.Test.Scenarios.WithProperty;
 using Xunit;
 
 namespace Autofac.Test
@@ -91,5 +93,33 @@ public void WhenPredicateAndValueParameterSupplied_PassedToComponent()
             Assert.Equal(a, result.A);
             Assert.Equal(b, result.B);
         }
+
+        [Fact]
+        public void RegisterPropertyWithExpression()
+        {
+            const string a = "Hello";
+            const bool b = true;
+            var builder = new ContainerBuilder();
+
+            builder.RegisterType<WithProps>()
+                .WithProperty(x => x.A, a)
+                .WithProperty(x => x.B, b);
+
+            var container = builder.Build();
+            var result = container.Resolve<WithProps>();
+
+            Assert.Equal(a, result.A);
+            Assert.Equal(b, result.B);
+        }
+
+        [Fact]
+        public void RegisterPropertyWithExpressionFieldExceptions()
+        {
+            const string a = "Hello";
+            var builder = new ContainerBuilder();
+
+            Assert.Throws<ArgumentOutOfRangeException>(() =>
+                builder.RegisterType<WithProps>().WithProperty(x => x._field, a));
+        }
     }
 }

test/Autofac.Test/Scenarios/WithProperty/WithProps.cs

@@ -0,0 +1,11 @@
+namespace Autofac.Test.Scenarios.WithProperty
+{
+    public class WithProps
+    {
+        public string A { get; set; }
+
+        public bool B { get; set; }
+
+        public string _field;
+    }
+}