protected override ShapedQueryExpression TranslateTake(ShapedQueryExpression source, Expression count)
{
if (source == null)
{
throw new ArgumentNullException(nameof(source));
}
if (count == null)
{
throw new ArgumentNullException(nameof(count));
}
var selectExpression = (SelectExpression)source.QueryExpression;
var translation = _sqlTranslator.Translate(count);
if (translation != null)
{
selectExpression.ApplyLimit(translation);
return(source);
}
return(null);
}
public override Expression Visit(Expression expression)
{
if (expression == null)
{
return(null);
}
if (!(expression is NewExpression ||
expression is MemberInitExpression ||
expression is EntityShaperExpression ||
expression is IncludeExpression))
{
// This skips the group parameter from GroupJoin
if (expression is ParameterExpression parameter &&
parameter.Type.IsGenericType &&
parameter.Type.GetGenericTypeDefinition() == typeof(IEnumerable <>))
{
return(parameter);
}
if (_clientEval)
{
switch (expression)
{
case ConstantExpression _:
return(expression);
case ParameterExpression parameterExpression:
return(Expression.Call(
_getParameterValueMethodInfo.MakeGenericMethod(parameterExpression.Type),
QueryCompilationContext.QueryContextParameter,
Expression.Constant(parameterExpression.Name)));
case MaterializeCollectionNavigationExpression materializeCollectionNavigationExpression:
return(_selectExpression.AddCollectionProjection(
_queryableMethodTranslatingExpressionVisitor.TranslateSubquery(
materializeCollectionNavigationExpression.Subquery),
materializeCollectionNavigationExpression.Navigation, null));
case MethodCallExpression methodCallExpression:
{
if (methodCallExpression.Method.IsGenericMethod &&
methodCallExpression.Method.DeclaringType == typeof(Enumerable) &&
methodCallExpression.Method.Name == nameof(Enumerable.ToList))
{
var elementType = methodCallExpression.Method.GetGenericArguments()[0];
var result = _queryableMethodTranslatingExpressionVisitor.TranslateSubquery(methodCallExpression.Arguments[0]);
return(_selectExpression.AddCollectionProjection(result, null, elementType));
}
var subquery = _queryableMethodTranslatingExpressionVisitor.TranslateSubquery(methodCallExpression);
if (subquery != null)
{
if (subquery.ResultCardinality == ResultCardinality.Enumerable)
{
return(_selectExpression.AddCollectionProjection(subquery, null, subquery.ShaperExpression.Type));
}
}
break;
}
}
var translation = _sqlTranslator.Translate(expression);
return(translation == null
? base.Visit(expression)
: new ProjectionBindingExpression(_selectExpression, _selectExpression.AddToProjection(translation), expression.Type));
}
else
{
var translation = _sqlTranslator.Translate(expression);
if (translation == null)
{
return(null);
}
_projectionMapping[_projectionMembers.Peek()] = translation;
return(new ProjectionBindingExpression(_selectExpression, _projectionMembers.Peek(), expression.Type));
}
}
return(base.Visit(expression));
}
