[AI Agents] Fix Azure#50993 (Azure#51094)

Author: glharper

sdk/ai/Azure.AI.Agents.Persistent/src/Custom/PersistentAgentsNamedToolChoiceType.Serialization.cs

@@ -0,0 +1,62 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+#nullable disable
+
+using System;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace Azure.AI.Agents.Persistent
+{
+    /// <summary> Available tool types for agents named tools. </summary>
+    [JsonConverter(typeof(PersistentAgentsNamedToolChoiceTypeConverter))]
+    public readonly partial struct PersistentAgentsNamedToolChoiceType
+    {
+    }
+
+    /// <summary>
+    /// Custom JSON converter for PersistentAgentsNamedToolChoiceType.
+    /// </summary>
+    internal class PersistentAgentsNamedToolChoiceTypeConverter : JsonConverter<PersistentAgentsNamedToolChoiceType>
+    {
+        /// <summary>
+        /// Reads and converts the JSON to PersistentAgentsNamedToolChoiceType.
+        /// </summary>
+        /// <param name="reader">The reader.</param>
+        /// <param name="typeToConvert">The type to convert.</param>
+        /// <param name="options">An object that specifies serialization options to use.</param>
+        /// <returns>The converted value.</returns>
+        public override PersistentAgentsNamedToolChoiceType Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        {
+            if (reader.TokenType == JsonTokenType.Null)
+            {
+                throw new JsonException("Cannot convert null value to PersistentAgentsNamedToolChoiceType.");
+            }
+
+            if (reader.TokenType != JsonTokenType.String)
+            {
+                throw new JsonException($"Cannot convert token type {reader.TokenType} to PersistentAgentsNamedToolChoiceType.");
+            }
+
+            string value = reader.GetString();
+            return new PersistentAgentsNamedToolChoiceType(value);
+        }
+
+        /// <summary>
+        /// Writes a PersistentAgentsNamedToolChoiceType as JSON.
+        /// </summary>
+        /// <param name="writer">The writer to write to.</param>
+        /// <param name="value">The value to convert to JSON.</param>
+        /// <param name="options">An object that specifies serialization options to use.</param>
+        public override void Write(Utf8JsonWriter writer, PersistentAgentsNamedToolChoiceType value, JsonSerializerOptions options)
+        {
+            if (writer == null)
+            {
+                throw new ArgumentNullException(nameof(writer));
+            }
+
+            writer.WriteStringValue(value.ToString());
+        }
+    }
+}