Switching from MemberInfo to AccessTools2
Introduction
Using any of the MemberInfo types is slow. Especially when they are not cached.
A better way for accessing type members is to create delegates, with them the access speed is on pair with direct access.
Harmony created a helper class AccessTools for those cases and BUTR created an extended version of it.
In this article we’ll show how you can speed up your code.
Caching
Always cache the reflection if it’s gonna be called multiple times.
Harmony
We strongly recommend to check first the Harmony Documentation as the code base is based on it.
You will also need Harmony.Extensions for the AccessTools2 class.
Accessing fields
// Usually it's done like this:
private static readonly FieldInfo? Info = AccessTools2.Field(typeof(LauncherModuleVM), "Info");
// And then invoked like this:
LauncherModuleVM obj = ...; // the LauncherModuleVM instance
if (Info is not null)
{
string str = Info.GetValue(obj);
Info.SetValue(obj, "newstr");
}
// Instead use AccessTools.FieldRef
private static readonly AccessTools.FieldRef<string, LauncherModuleVMType>? Info = AccessTools2.FieldRefAccess<string, LauncherModuleVMType>("Info");
LauncherModuleVM obj = ...; // the LauncherModuleVM instance
if (Info is not null)
{
string str = Info(obj);
Info(obj) = "newstr";
}
Calling methods
// Usually it's done like this:
private static readonly MethodInfo? Method = AccessTools2.Method(typeof(LauncherModuleVM), "Method");
// And then invoked like this:
LauncherModuleVM obj = ...; // the LauncherModuleVM instance
if (Method is not null)
{
bool b = Info.Invoke(obj, new object[] {});
}
// Instead use AccessTools.FieldRef
private delegate bool MethodDelegate(LauncherModuleVM instance);
private static readonly MethodDelegate Method = AccessTools2.GetDelegate<MethodDelegate>(typeof(LauncherModuleVM), "Method");
LauncherModuleVM obj = ...; // the LauncherModuleVM instance
if (Method is not null)
{
bool b = Info(obj);
}
Accessing properties
// Usually it's done like this:
private static readonly PropertyInfo? Name = AccessTools2.Property(typeof(LauncherModuleVM), "Name");
// And then invoked like this:
LauncherModuleVM obj = ...; // the LauncherModuleVM instance
if (Name is not null)
{
bool b = Info.GetValue(obj);
Info.SetValue(obj, true);
}
// Instead use AccessTools.FieldRef
private delegate bool GetNameDelegate(LauncherModuleVM instance);
private delegate void SetNameDelegate(LauncherModuleVM instance, bool @value);
private static readonly GetNameDelegate GetName = AccessTools2.GetPropertyGetterDelegate<GetNameDelegate>(typeof(LauncherModuleVM), "Name");
private static readonly SetNameDelegate SetName = AccessTools2.GetPropertySetterDelegate<SetNameDelegate>(typeof(LauncherModuleVM), "Name");
LauncherModuleVM obj = ...; // the LauncherModuleVM instance
if (GetName is not null && SetName is not null)
{
bool b = GetName(obj);
SetName(obj, true);
}