Use TryGet pattern to get BcpInterface from GLE

Author: arthurkehrwald

Runtime/MediaController/Text/MonitoredVariableText.cs

@@ -35,8 +35,7 @@ public abstract class MonitoredVariableText<TVar, TMessage> : MonitoredVariableT
 
         private void OnEnable()
         {
-            var bcpInterface = MpfGamelogicEngine.GetBcpInterface(this);
-            if (bcpInterface != null)
+            if (MpfGamelogicEngine.TryGetBcpInterface(this, out var bcpInterface))
             {
                 _monitor = CreateMonitor(bcpInterface);
                 SetText(_monitor.VarValue);

Runtime/MpfGamelogicEngine.cs

@@ -269,7 +269,10 @@ private async void OnDestroy()
             MpfWrangler.Dispose();
         }
 
-        public static BcpInterface GetBcpInterface(Component requestingComponent)
+        public static bool TryGetBcpInterface(
+            Component requestingComponent,
+            out BcpInterface bcpInterface
+        )
         {
             var gle = requestingComponent.GetComponentInParent<MpfGamelogicEngine>();
 
@@ -281,7 +284,8 @@ public static BcpInterface GetBcpInterface(Component requestingComponent)
             if (!Application.isPlaying)
             {
                 Logger.Error(string.Format(errorMessage, "the game is not running."));
-                return null;
+                bcpInterface = null;
+                return false;
             }
 
             if (gle == null)
@@ -295,7 +299,8 @@ public static BcpInterface GetBcpInterface(Component requestingComponent)
                             + "table or remove the component that requested the BCP interface."
                     )
                 );
-                return null;
+                bcpInterface = null;
+                return false;
             }
 
             if (gle._wranglerOptions.MediaController != MpfMediaController.Included)
@@ -308,18 +313,21 @@ public static BcpInterface GetBcpInterface(Component requestingComponent)
                             + "logic engine inspector."
                     )
                 );
-                return null;
+                bcpInterface = null;
+                return false;
             }
 
             if (gle.MpfWrangler == null)
             {
                 Logger.Error(
                     string.Format(errorMessage, "the game logic engine is not initialized.")
                 );
-                return null;
+                bcpInterface = null;
+                return false;
             }
 
-            return gle.MpfWrangler.BcpInterface;
+            bcpInterface = gle.MpfWrangler.BcpInterface;
+            return true;
         }
 
         public void DisplayChanged(DisplayFrameData displayFrameData) { }