Set `PropertyNamingPolicy` to `null` to keep original property name and dictionary key.

framework/src/Volo.Abp.Json.SystemTextJson/Volo/Abp/Json/SystemTextJson/AbpSystemTextJsonSerializer.cs

@@ -40,21 +40,10 @@ public class AbpSystemTextJsonSerializer : IJsonSerializer, ITransientDependency
             camelCase,
             indented,
             Options.JsonSerializerOptions
-        }, _ =>
+        }, _ => new JsonSerializerOptions(Options.JsonSerializerOptions)
         {
-            var settings = new JsonSerializerOptions(Options.JsonSerializerOptions);
-
-            if (camelCase)
-            {
-                settings.PropertyNamingPolicy = JsonNamingPolicy.CamelCase;
-            }
-
-            if (indented)
-            {
-                settings.WriteIndented = true;
-            }
-
-            return settings;
+            PropertyNamingPolicy = camelCase ? JsonNamingPolicy.CamelCase : null,
+            WriteIndented = indented
         });
     }
 }

framework/test/Volo.Abp.Json.Tests/Volo/Abp/Json/AbpNewtonsoftSerializerProviderTests.cs

@@ -0,0 +1,52 @@
+using System;
+using System.Collections.Generic;
+using Shouldly;
+using Volo.Abp.Json.Newtonsoft;
+using Xunit;
+
+namespace Volo.Abp.Json;
+
+public class AbpNewtonsoftSerializerProviderTests : AbpJsonNewtonsoftJsonTestBase
+{
+    protected AbpNewtonsoftJsonSerializer JsonSerializer;
+
+    public AbpNewtonsoftSerializerProviderTests()
+    {
+        JsonSerializer = GetRequiredService<AbpNewtonsoftJsonSerializer>();
+    }
+
+    public class File
+    {
+        public string FileName { get; set; }
+
+        public Dictionary<string, int> ExtraProperties { get; set; }
+    }
+
+    [Fact]
+    public void Serialize_Deserialize_Test()
+    {
+        var defaultIndent = "  "; // Default indent is 2 spaces
+        var newLine = Environment.NewLine;
+        var file = new File()
+        {
+            FileName = "abp",
+            ExtraProperties = new Dictionary<string, int>()
+            {
+                { "One", 1 },
+                { "Two", 2 }
+            }
+        };
+
+        var json = JsonSerializer.Serialize(file, camelCase: true);
+        json.ShouldBe("{\"fileName\":\"abp\",\"extraProperties\":{\"One\":1,\"Two\":2}}");
+
+        json = JsonSerializer.Serialize(file, camelCase: true, indented: true);
+        json.ShouldBe($"{{{newLine}{defaultIndent}\"fileName\": \"abp\",{newLine}{defaultIndent}\"extraProperties\": {{{newLine}{defaultIndent}{defaultIndent}\"One\": 1,{newLine}{defaultIndent}{defaultIndent}\"Two\": 2{newLine}{defaultIndent}}}{newLine}}}");
+
+        json = JsonSerializer.Serialize(file, camelCase: false);
+        json.ShouldBe("{\"FileName\":\"abp\",\"ExtraProperties\":{\"One\":1,\"Two\":2}}");
+
+        json = JsonSerializer.Serialize(file, camelCase: false, indented: true);
+        json.ShouldBe($"{{{newLine}{defaultIndent}\"FileName\": \"abp\",{newLine}{defaultIndent}\"ExtraProperties\": {{{newLine}{defaultIndent}{defaultIndent}\"One\": 1,{newLine}{defaultIndent}{defaultIndent}\"Two\": 2{newLine}{defaultIndent}}}{newLine}}}");
+    }
+}

framework/test/Volo.Abp.Json.Tests/Volo/Abp/Json/AbpSystemTextJsonSerializerProvider_Tests.cs

@@ -1,4 +1,6 @@
 using System;
+using System.Collections.Generic;
+using System.Text.Json;
 using Microsoft.Extensions.DependencyInjection;
 using Shouldly;
 using Volo.Abp.Data;
@@ -23,6 +25,13 @@ public abstract class AbpSystemTextJsonSerializerProviderTestBase : AbpJsonSyste
         public string Name { get; set; }
     }
 
+    public class File
+    {
+        public string FileName { get; set; }
+
+        public Dictionary<string, int> ExtraProperties { get; set; }
+    }
+
     public class FileWithBoolean
     {
         public string Name { get; set; }
@@ -74,6 +83,34 @@ public abstract class AbpSystemTextJsonSerializerProviderTestBase : AbpJsonSyste
 
 public class AbpSystemTextJsonSerializerProviderTests : AbpSystemTextJsonSerializerProviderTestBase
 {
+    [Fact]
+    public void Serialize_Deserialize_Test()
+    {
+        var defaultIndent = "  "; // Default indent is 2 spaces
+        var newLine = Environment.NewLine;
+        var file = new File()
+        {
+            FileName = "abp",
+            ExtraProperties = new Dictionary<string, int>()
+            {
+                { "One", 1 },
+                { "Two", 2 }
+            }
+        };
+
+        var json = JsonSerializer.Serialize(file, camelCase: true);
+        json.ShouldBe("{\"fileName\":\"abp\",\"extraProperties\":{\"One\":1,\"Two\":2}}");
+
+        json = JsonSerializer.Serialize(file, camelCase: true, indented: true);
+        json.ShouldBe($"{{{newLine}{defaultIndent}\"fileName\": \"abp\",{newLine}{defaultIndent}\"extraProperties\": {{{newLine}{defaultIndent}{defaultIndent}\"One\": 1,{newLine}{defaultIndent}{defaultIndent}\"Two\": 2{newLine}{defaultIndent}}}{newLine}}}");
+
+        json = JsonSerializer.Serialize(file, camelCase: false);
+        json.ShouldBe("{\"FileName\":\"abp\",\"ExtraProperties\":{\"One\":1,\"Two\":2}}");
+
+        json = JsonSerializer.Serialize(file, camelCase: false, indented: true);
+        json.ShouldBe($"{{{newLine}{defaultIndent}\"FileName\": \"abp\",{newLine}{defaultIndent}\"ExtraProperties\": {{{newLine}{defaultIndent}{defaultIndent}\"One\": 1,{newLine}{defaultIndent}{defaultIndent}\"Two\": 2{newLine}{defaultIndent}}}{newLine}}}");
+    }
+
     [Fact]
     public void Serialize_Deserialize_With_Boolean()
     {