protected override Expression VisitMethodCall(MethodCallExpression node)
{
Expression expression = base.Visit(node.Arguments[0]);
if (node.Method.DeclaringType == typeof(EntityFrameworkQueryableExtensions))
{
if (node.Method.Name == nameof(EntityFrameworkQueryableExtensions.Include) ||
node.Method.Name == nameof(EntityFrameworkQueryableExtensions.ThenInclude))
{
var visitor = new PropertyVisitor();
visitor.Visit(node.Arguments[1]);
if (visitor.Filter == null)
{
node = Expression.Call(null, node.Method, new Expression[] { expression, node.Arguments[1] });
}
else
{
if (node.Method.Name == nameof(EntityFrameworkQueryableExtensions.Include))
{
Type entityType = node.Method.GetGenericArguments()[0];
MethodInfo method = node.Method.GetGenericMethodDefinition().MakeGenericMethod(entityType, visitor.Property.Type);
LambdaExpression lambda = Expression.Lambda(visitor.Property, visitor.Parameter);
node = Expression.Call(null, method, new Expression[] { node.Arguments[0], lambda });
}
else
{
Type entityType = node.Method.GetGenericArguments()[0];
Type previousPropertyType = node.Method.GetGenericArguments()[1];
MethodInfo method = node.Method.GetGenericMethodDefinition().MakeGenericMethod(entityType, previousPropertyType, visitor.Property.Type);
LambdaExpression lambda = Expression.Lambda(visitor.Property, visitor.Parameter);
node = Expression.Call(null, method, new Expression[] { node.Arguments[0], lambda });
}
}
_includes.Add(new Include(visitor.Property.Member as PropertyInfo, visitor.Filter, false));
}
}
else if (node.Method.DeclaringType == typeof(Queryable) && node.Method.Name == nameof(Queryable.Select))
{
var visitor = new NewVisitor();
visitor.Visit(node.Arguments[1]);
_includes.AddRange(visitor.SelectProperties.Select(p => new Include(p, null, true)));
}
else
{
if (node.Arguments.Count == 1)
{
node = Expression.Call(node.Object, node.Method, expression);
}
else
{
node = Expression.Call(node.Object, node.Method, expression, node.Arguments[1]);
}
}
return(node);
}
static void ShowVisitorPattern()
{
List <BallBase> ballBases = new List <BallBase>()
{
new BasketBall(),
new BasketBall(),
new FootBall(),
new BasketBall(),
new FootBall()
};
BallVisitorBase oldVisitor = new OldVisitor();
foreach (var ball in ballBases)
{
ball.Play(oldVisitor);
}
Console.WriteLine("=========================================");
BallVisitorBase newVisitor = new NewVisitor();
foreach (var ball in ballBases)
{
ball.Play(newVisitor);
}
}
protected override Expression VisitMethodCall(MethodCallExpression node)
{
Expression expression = base.Visit(node.Arguments[0]);
if (node.Method.DeclaringType == typeof(EntityFrameworkQueryableExtensions))
{
if (node.Method.Name == nameof(EntityFrameworkQueryableExtensions.Include) ||
node.Method.Name == nameof(EntityFrameworkQueryableExtensions.ThenInclude))
{
var visitor = new PropertyVisitor(_isDatabaseNullHighestValue);
visitor.Visit(node.Arguments[1]);
if (_metadataProvider.IsNotMapped((PropertyInfo)visitor.PropertyExpression.Member))
{
_includes.Add(new EfInclude(visitor.PropertyExpression.Member as PropertyInfo, visitor.Filter, visitor.IsOrdered));
return(node.Arguments[0]);
}
if (visitor.Filter == null)
{
node = Expression.Call(null, node.Method, new Expression[] { expression, node.Arguments[1] });
}
else
{
Type entityType = node.Method.GetGenericArguments()[0];
MethodInfo method;
if (node.Method.Name == nameof(EntityFrameworkQueryableExtensions.Include))
{
method = node.Method.GetGenericMethodDefinition().MakeGenericMethod(entityType, visitor.PropertyExpression.Type);
}
else
{
Type previousPropertyType = node.Method.GetGenericArguments()[1];
method = node.Method.GetGenericMethodDefinition().MakeGenericMethod(entityType, previousPropertyType, visitor.PropertyExpression.Type);
}
LambdaExpression lambda = Expression.Lambda(visitor.PropertyExpression, visitor.Parameter);
node = Expression.Call(null, method, new Expression[] { expression, lambda });
}
PropertyInfo parentProperty = null;
if (node.Method.Name == nameof(EntityFrameworkQueryableExtensions.ThenInclude))
{
var parentVisitor = new PropertyVisitor(_isDatabaseNullHighestValue);
parentVisitor.Visit(node.Arguments[0]);
parentProperty = parentVisitor.PropertyExpression.Member as PropertyInfo;
}
_includes.Add(new EfInclude(visitor.PropertyExpression.Member as PropertyInfo, visitor.Filter, visitor.IsOrdered, parentProperty));
return(node);
}
}
else if (node.Method.DeclaringType == typeof(Queryable) && node.Method.Name == nameof(Queryable.Select))
{
var visitor = new NewVisitor();
visitor.Visit(node.Arguments[1]);
_includes.AddRange(visitor.SelectProperties.Select(p => new EfInclude(p, null, false)));
}
else if (node.Method.DeclaringType == typeof(Queryable) && node.Method.Name == nameof(Queryable.GroupJoin))
{
Type outerType = node.Arguments[0].Type.GetGenericArguments()[0];
Type innerType = node.Arguments[1].Type.GetGenericArguments()[0];
List <PropertyInfo> navigationProperties = outerType.GetProperties().Where(p => p.PropertyType == innerType).ToList();
if (navigationProperties.Count == 0)
{
Type collectionType = typeof(IEnumerable <>).MakeGenericType(innerType);
PropertyInfo navigationProperty = outerType.GetProperties().Where(p => collectionType.IsAssignableFrom(p.PropertyType)).Single();
_includes.Add(new EfInclude(navigationProperty, null, false));
}
else if (navigationProperties.Count == 1)
{
_includes.Add(new EfInclude(navigationProperties[0], null, false));
}
else
{
LambdaExpression outerKeySelector;
if (node.Arguments[2] is UnaryExpression unaryExpression)
{
outerKeySelector = (LambdaExpression)unaryExpression.Operand;
}
else
{
outerKeySelector = (LambdaExpression)node.Arguments[2];
}
if (outerKeySelector.Body is MemberExpression propertyExpression)
{
PropertyInfo navigationProperty = _metadataProvider.GetForeignKey((PropertyInfo)propertyExpression.Member).Single();
_includes.Add(new EfInclude(navigationProperty, null, false));
}
else if (outerKeySelector.Body is NewExpression newExpression)
{
List <PropertyInfo> properties = newExpression.Arguments.Select(a => (PropertyInfo)((MemberExpression)a).Member).ToList();
foreach (PropertyInfo navigationProperty in navigationProperties)
{
PropertyInfo[] structuralProperties = _metadataProvider.GetForeignKey(navigationProperty);
if (!structuralProperties.Except(properties).Any())
{
_includes.Add(new EfInclude(navigationProperty, null, false));
break;
}
}
}
}
}
var arguments = new Expression[node.Arguments.Count];
node.Arguments.CopyTo(arguments, 0);
arguments[0] = expression;
return(Expression.Call(node.Object, node.Method, arguments));
}