public JoinExpression VisitJoin(MethodCallExpression expression)
{
// Handle the default Queryable extension Join
if (IsDeclaring(expression, typeof(Queryable), typeof(Enumerable)))
{
// Resolve the sources
ASourceExpression outer = Visit <ASourceExpression>(expression.Arguments[0]);
ASourceExpression inner = Visit <ASourceExpression>(expression.Arguments[1]);
// Set the active expressions (so fields calls can find their expression)
sources = new[] { outer, inner };
// Create the predicate
LambdaExpression outerLambda = (LambdaExpression)StripQuotes(expression.Arguments[2]);
LambdaExpression innerLambda = (LambdaExpression)StripQuotes(expression.Arguments[3]);
FieldExpression outerField = Visit <FieldExpression>(outerLambda.Body);
FieldExpression innerField = Visit <FieldExpression>(innerLambda.Body);
APredicateExpression predicate = new CompositeExpression(outerField, innerField, CompositeOperator.Equal);
// Decode the result selector
IEnumerable <FieldExpression> fields = DecodeJoinSelector(expression.Arguments[4], outer.Fields, inner.Fields);
// Create the expression
return(new JoinExpression(outer, inner, predicate, fields, JoinType.Inner));
}
// Handle the default SqlQueryableHelper extension Join
if (IsDeclaring(expression, typeof(SqlQueryableHelper)))
{
// Resolve the sources
ASourceExpression outer = Visit <ASourceExpression>(expression.Arguments[0]);
ASourceExpression inner = Visit <ASourceExpression>(expression.Arguments[1]);
// Set the active expressions (so fields calls can find their expression)
sources = new[] { outer, inner };
// Create the predicate
LambdaExpression predicateLambda = (LambdaExpression)StripQuotes(expression.Arguments[2]);
APredicateExpression predicate = Visit <APredicateExpression>(predicateLambda.Body);
// Decode the result selector
IEnumerable <FieldExpression> fields = DecodeJoinSelector(expression.Arguments[3], outer.Fields, inner.Fields);
// Resolve the join type
ConstantExpression joinType = (ConstantExpression)expression.Arguments[4];
// Create the expression
return(new JoinExpression(outer, inner, predicate, fields, (JoinType)joinType.Value));
}
throw new MethodTranslationException(expression.Method);
}
/// <summary>
/// Visits the specified expression.
/// </summary>
/// <param name="expression">The expression to visit.</param>
public virtual Expression VisitComposite(CompositeExpression expression)
{
if (expression == null)
{
throw new ArgumentNullException(nameof(expression));
}
Builder.Append("(");
Visit(expression.Left);
if (expression.Operator == CompositeOperator.And)
{
Builder.Append(" and ");
}
else if (expression.Operator == CompositeOperator.Or)
{
Builder.Append(" or ");
}
else if (expression.Operator == CompositeOperator.GreaterThan)
{
Builder.Append(" > ");
}
else if (expression.Operator == CompositeOperator.GreaterThanOrEqual)
{
Builder.Append(" >= ");
}
else if (expression.Operator == CompositeOperator.LessThan)
{
Builder.Append(" < ");
}
else if (expression.Operator == CompositeOperator.LessThanOrEqual)
{
Builder.Append(" <= ");
}
else if (expression.Operator == CompositeOperator.Equal)
{
if (expression.Right is NullExpression)
{
Builder.Append(" is ");
}
else
{
Builder.Append(" = ");
}
}
else if (expression.Operator == CompositeOperator.NotEqual)
{
if (expression.Right is NullExpression)
{
Builder.Append(" is not ");
}
else
{
Builder.Append(" <> ");
}
}
else
{
throw new NotSupportedException($"Cannot generate sql for '{expression.Operator}' operator of {nameof(CompositeExpression)}.");
}
Visit(expression.Right);
Builder.Append(")");
return(expression);
}
