/// <summary>
/// Visits the children of the <see cref="T:System.Linq.Expressions.MethodCallExpression"/>.
/// </summary>
/// <param name="node">The expression to visit.</param>
/// <returns>
/// The modified expression, if it or any subexpression was modified; otherwise, returns the
/// original expression.
/// </returns>
/// <exception cref="NotSupportedException"></exception>
protected override Expression?VisitMethodCall(MethodCallExpression node)
{
if (node is null)
{
return(node);
}
if (node.Method.DeclaringType == typeof(Queryable))
{
if (node.Method.Name == "Where")
{
node = (MethodCallExpression)Evaluator.PartialEval(node);
Visit(node.Arguments[0]);
var lambda = (LambdaExpression)StripQuotes(node.Arguments[1]);
var CurrentClause = new WhereVisitor <TObject>(Count).WhereProjection(lambda.Body);
++Count;
foreach (var Source in Builders.Keys)
{
Builders[Source].WhereClause.Combine(CurrentClause.Copy());
}
return(node);
}
if (node.Method.Name == "Select")
{
Visit(node.Arguments[0]);
var lambda = (LambdaExpression)StripQuotes(node.Arguments[1]);
var Columns = new ColumnProjector().ProjectColumns(lambda.Body);
foreach (var Source in Builders.Keys)
{
var ParentMappings = Source.GetChildMappings(typeof(TObject))
.SelectMany(x => Source.GetParentMapping(x.ObjectType))
.Distinct();
foreach (var Column in Columns)
{
if (ParentMappings.Any(x => x.ContainsProperty(Column.Name)))
{
Builders[Source].SelectValues.Add(Column);
}
}
}
return(node);
}
if (node.Method.Name == "ThenBy" ||
node.Method.Name == "OrderBy" ||
node.Method.Name == "OrderByDescending" ||
node.Method.Name == "ThenByDescending")
{
Visit(node.Arguments[0]);
var lambda = (LambdaExpression)StripQuotes(node.Arguments[1]);
var Columns = new ColumnProjector().ProjectColumns(lambda.Body);
foreach (var Source in Builders.Keys)
{
var ParentMappings = Source.GetChildMappings(typeof(TObject))
.SelectMany(x => Source.GetParentMapping(x.ObjectType))
.Distinct();
foreach (var Column in Columns)
{
if (ParentMappings.Any(x => x.ContainsProperty(Column.Name)))
{
Builders[Source].OrderByValues.Add(new OrderByClause(Builders[Source].OrderByValues.Count,
Column,
node.Method.Name.Contains("Descending", StringComparison.OrdinalIgnoreCase) ? Direction.Descending : Direction.Ascending));
}
}
}
return(node);
}
if (node.Method.Name == "Distinct")
{
Visit(node.Arguments[0]);
foreach (var Source in Builders.Keys)
{
Builders[Source].Distinct = true;
}
return(node);
}
if (node.Method.Name == "First" ||
node.Method.Name == "FirstOrDefault" ||
node.Method.Name == "Single" ||
node.Method.Name == "SingleOrDefault")
{
Visit(node.Arguments[0]);
foreach (var Source in Builders.Keys)
{
Builders[Source].Top = 1;
}
return(node);
}
if (node.Method.Name == "Take")
{
Visit(node.Arguments[0]);
foreach (var Source in Builders.Keys)
{
Builders[Source].Top = (int)((node.Arguments[1] as ConstantExpression)?.Value ?? 1);
}
return(node);
}
if (node.Method.Name == "Skip")
{
Visit(node.Arguments[0]);
foreach (var Source in Builders.Keys)
{
Builders[Source].Skip = (int)((node.Arguments[1] as ConstantExpression)?.Value ?? 1);
}
return(node);
}
if (node.Method.Name == "Count")
{
Visit(node.Arguments[0]);
foreach (var Source in Builders.Keys)
{
Builders[Source].Count = true;
}
return(node);
}
}
throw new NotSupportedException($"The method '{node.Method.Name}' is not supported.");
}