ReflectionHelper

ReflectionHelper is the low-level utility that all other APIs use internally. You only need it directly when you want to access game data that no API exposes yet.

The auto-property naming rule

C# auto-properties compile to a hidden backing field named <PropertyName>k__BackingField. When a game field is an auto-property you must use this exact name:

var vworld   = ReflectionHelper.GetFieldValue(hub, "<vworld>k__BackingField");
var currency = ReflectionHelper.GetFieldValue<int>(room, "<Currency>k__BackingField");

Plain fields use their name directly:

var vrm   = ReflectionHelper.GetFieldValue(vworld, "_vRoomManager");
var pdata = ReflectionHelper.GetFieldValue(hub, "pdata");

If you're not sure which pattern a field uses, run Fish AI Reader on Assembly-CSharp.dll and look at the field name in the output.

Field access

GetFieldValue()

public static object? GetFieldValue(object target, string fieldName)
public static object? GetFieldValue(Type type, string fieldName)

GetFieldValue<T>()

public static T GetFieldValue<T>(object target, string fieldName)
public static T GetFieldValue<T>(Type type, string fieldName)

Returns default if the field is null or not found — never throws.

var room = RoomAPI.GetCurrentRoom();
int day  = ReflectionHelper.GetFieldValue<int>(room, "_currentDay");
long tick = ReflectionHelper.GetFieldValue<long>(room, "_currentTick");

SetFieldValue()

public static void SetFieldValue(object target, string fieldName, object value)
public static void SetFieldValue(Type type, string fieldName, object value)

ReflectionHelper.SetFieldValue(room, "_currentDay", 3);

warning

Setting internal fields can break game logic. Only do this if you know what the field controls.

Method invocation

InvokeMethod()

public static object? InvokeMethod(object target, string methodName, params object[] parameters)
public static object? InvokeMethod(Type type, string methodName, params object[] parameters)

var room = RoomAPI.GetCurrentRoom();

bool playable = ReflectionHelper.InvokeMethod(room, "IsPlayable") is bool b && b;
bool allDead  = ReflectionHelper.InvokeMethod(room, "IsAllPlayerDead") is bool d && d;

With parameters:

var waitingRoom = ServerNetworkAPI.GetWaitingRoom();
var result = ReflectionHelper.InvokeMethod(waitingRoom, "CanEnterChannel", playerUID);

InvokeMethod<T>()

public static T? InvokeMethod<T>(object target, string methodName, params object[] parameters) where T : class

Property access

GetPropertyValue() / GetPropertyValue<T>()

public static object? GetPropertyValue(object target, string propertyName)
public static T GetPropertyValue<T>(object target, string propertyName)

SetPropertyValue()

public static void SetPropertyValue(object target, string propertyName, object value)

Finding field names with Fish AI Reader

When a game update breaks something, run Fish AI Reader to get the current field names:

FishAIReader.exe Assembly-CSharp.dll -o report.json

Then search the JSON for the type you care about and check its fields array. The name property is exactly what you pass to GetFieldValue.

Full example — inspect a room

var room = RoomAPI.GetCurrentRoom();
if (room == null) return;

var type = room.GetType();
MelonLogger.Msg($"Type: {type.Name}");

foreach (var field in type.GetFields(
    System.Reflection.BindingFlags.NonPublic |
    System.Reflection.BindingFlags.Instance  |
    System.Reflection.BindingFlags.Public))
{
    var value = ReflectionHelper.GetFieldValue(room, field.Name);
    MelonLogger.Msg($"  {field.Name} = {value}");
}

See also

• CoreAPI — shows the full Hub → VWorld chain with real field names
• RoomAPI — uses reflection for all room field access