Updates "DateTime?" as well

gistfile1.cs

    /// <summary>
    /// Fixes all DateTime and DateTime? properties to be datetime2 in SQL Server.
    /// from http://flashfm.blogspot.ch/2011/11/entity-framework-41-code-first-fixing.html
    /// </summary>
    public static class ContextUtils
    {
        public static void FixDateTimeColumns(DbContext context, DbModelBuilder modelBuilder)
        {
            var contextProps = context.GetType().GetProperties(BindingFlags.Instance | BindingFlags.Public);
            foreach (var contextProp in contextProps)
            {
                var propType = contextProp.PropertyType;

                if (!propType.IsGenericType)
                    continue;

                if (propType.GetGenericTypeDefinition() != typeof(DbSet<>))
                    continue;

                var modelType = propType.GetGenericArguments()[0];

                // call generic Entity<> method
                var entityTypeConfig = modelBuilder.GetType().GetMethod("Entity").MakeGenericMethod(modelType).Invoke(modelBuilder, null);

                var modelProps = modelType.GetProperties(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
                foreach (var modelProp in modelProps)
                {
                    var modelPropType = modelProp.PropertyType;
                    if (modelPropType == typeof(DateTime))
                    {
                        var typeParam = Expression.Parameter(modelType, "p");
                        var body = Expression.Property(typeParam, modelProp);
                        var lambda = Expression.Lambda(body, typeParam);

                        // call Property method
                        var propertyMethod = GetPropertyMethodForDateTime(entityTypeConfig);
                        var propConfig =
                            (DateTimePropertyConfiguration)propertyMethod.Invoke(entityTypeConfig, new[] { lambda });

                        // set the type
                        propConfig.HasColumnType("datetime2");
                    }
                    else if (modelPropType == typeof(DateTime?))
                    {
                        var typeParam = Expression.Parameter(modelType, "p");
                        var body = Expression.Property(typeParam, modelProp);
                        var lambda = Expression.Lambda(body, typeParam);

                        // call Property method
                        var propertyMethod = GetPropertyMethodForNullableDatetime(entityTypeConfig);
                        var propConfig =
                            (DateTimePropertyConfiguration)propertyMethod.Invoke(entityTypeConfig, new[] { lambda });

                        // set the type
                        propConfig.HasColumnType("datetime2");
                    }

                    // prepare lambda (Expression<Func<TStructuralType, DateTime>>)
                }
            }
        }

        private static MethodInfo GetPropertyMethodForDateTime(object entityTypeConfig)
        {
            foreach (var method in entityTypeConfig.GetType().GetMethods(BindingFlags.Instance | BindingFlags.Public))
            {
                if (method.Name == "Property")
                {
                    var mParams = method.GetParameters();
                    if (mParams.Length == 1)
                    {
                        var p = mParams[0];
                        var f = p.ParameterType.GetGenericArguments()[0]; // Func<TStructuralType, DateTime>
                        var args = f.GetGenericArguments();
                        if (args.Length == 2 && args[1] == typeof(DateTime))
                        {
                            return method;
                        }
                    }
                }
            }

            throw new InvalidOperationException("Could not find appropriate Property method.");
        }

        private static MethodInfo GetPropertyMethodForNullableDatetime(object entityTypeConfig)
        {
            foreach (var method in entityTypeConfig.GetType().GetMethods(BindingFlags.Instance | BindingFlags.Public))
            {
                if (method.Name == "Property")
                {
                    var mParams = method.GetParameters();
                    if (mParams.Length == 1)
                    {
                        var p = mParams[0];
                        var f = p.ParameterType.GetGenericArguments()[0]; // Func<TStructuralType, DateTime>
                        var args = f.GetGenericArguments();
                        if (args.Length == 2 && args[1] == typeof(DateTime?))
                        {
                            return method;
                        }
                    }
                }
            }

            throw new InvalidOperationException("Could not find appropriate Property method.");
        }
    }