Abstract generated method override check into AST extensions.

src/AST/FunctionExtensions.cs

@@ -74,6 +74,16 @@ namespace CppSharp.AST
             return @params;
         }
 
+        public static bool IsGeneratedOverride(this Method method)
+        {
+            // Check if overriding a function from a secondary base.
+            var @class = method.Namespace as Class;
+            Method rootBaseMethod;
+            return method.IsOverride &&
+                (rootBaseMethod = @class.GetBaseMethod(method, true)) != null &&
+                rootBaseMethod.IsGenerated && rootBaseMethod.IsVirtual;
+        }
+
         public static bool CanOverride(this Method @override, Method method)
         {
             return (method.OriginalName == @override.OriginalName &&

src/Generator/Generators/CLI/CLIHeaders.cs

@@ -713,9 +713,7 @@ namespace CppSharp.Generators.CLI
             Write(")");
 
             if (method.IsOverride)
-            {
                 Write(" override");
-            }
         }
 
         public void GenerateMethod(Method method)

src/Generator/Generators/CSharp/CSharpSources.cs

@@ -2078,13 +2078,7 @@ namespace CppSharp.Generators.CSharp
 
         public override void GenerateMethodSpecifier(Method method, Class @class)
         {
-            // check if overriding a function from a secondary base
-            Method rootBaseMethod;
-            var isOverride = method.IsOverride &&
-                (rootBaseMethod = @class.GetBaseMethod(method, true)) != null &&
-                rootBaseMethod.IsGenerated && rootBaseMethod.IsVirtual;
-
-            if (method.IsVirtual && !isOverride && !method.IsOperator && !method.IsPure)
+            if (method.IsVirtual && !method.IsGeneratedOverride() && !method.IsOperator && !method.IsPure)
                 Write("virtual ");
 
             var isBuiltinOperator = method.IsOperator &&
@@ -2093,10 +2087,8 @@ namespace CppSharp.Generators.CSharp
             if (method.IsStatic || isBuiltinOperator)
                 Write("static ");
 
-            if (isOverride)
-            {
+            if (method.IsGeneratedOverride())
                 Write("override ");
-            }
 
             if (method.IsPure)
                 Write("abstract ");