Support ToString in RepeatedField and MapField.

This changes how we approach JSON formatting in general - instead of looking  at the field a value came from, we just look at the type of the value. It's possible this *could* be slightly inefficient, but if we start caring about JSON performance deeply, we'll probably want to rewrite all of this anyway. It's definitely simpler this way.

When we support dynamic messages, we'll need to modify JsonFormatter to handle enum values, as they won't come be "real" .NET enums at that point. It shouldn't be hard to do though.

1 files changed, 16 insertions, 0 deletions

diff --git a/csharp/src/Google.Protobuf/Collections/RepeatedField.cs b/csharp/src/Google.Protobuf/Collections/RepeatedField.cs
index d9ced6ec..e3f65afe 100644
--- a/csharp/src/Google.Protobuf/Collections/RepeatedField.cs
+++ b/csharp/src/Google.Protobuf/Collections/RepeatedField.cs
@@ -33,6 +33,7 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Text;
 using Google.Protobuf.Compatibility;
 
 namespace Google.Protobuf.Collections
@@ -41,6 +42,10 @@ namespace Google.Protobuf.Collections
     /// The contents of a repeated field: essentially, a collection with some extra
     /// restrictions (no null values) and capabilities (deep cloning).
     /// </summary>
+    /// <remarks>
+    /// This implementation does not generally prohibit the use of types which are not
+    /// supported by Protocol Buffers but nor does it guarantee that all operations will work in such cases.
+    /// </remarks>
     /// <typeparam name="T">The element type of the repeated field.</typeparam>
     public sealed class RepeatedField<T> : IList<T>, IList, IDeepCloneable<RepeatedField<T>>, IEquatable<RepeatedField<T>>
     {
@@ -465,6 +470,17 @@ namespace Google.Protobuf.Collections
         }
 
         /// <summary>
+        /// Returns a string representation of this repeated field, in the same
+        /// way as it would be represented by the default JSON formatter.
+        /// </summary>
+        public override string ToString()
+        {
+            var builder = new StringBuilder();
+            JsonFormatter.Default.WriteList(builder, this);
+            return builder.ToString();
+        }
+
+        /// <summary>
         /// Gets or sets the item at the specified index.
         /// </summary>
         /// <value>