public override Expression Output(OneToManyQueryDetailWalkInfo walkInfo)
{
var expression = BuildWhereExpression(walkInfo);
expression = BuildOrderExpression(expression, walkInfo);
expression = BuildSelectExpression(expression, walkInfo);
var toListMethod = MethodProvider.MakeGenericMethod(typeof(Enumerable), "ToList",
new Type[] { typeof(IEnumerable <>) },
new Type[] { walkInfo.Type });
return(Expression.Call(toListMethod, expression));
}
private Expression BuildSelectExpression(Expression expression, OneToManyQueryDetailWalkInfo walkInfo)
{
var memberInitializationExpression = Expression.Lambda(
typeof(Func <,>).MakeGenericType(walkInfo.Type, walkInfo.Type),
BuildMemberInitExpression(),
walkInfo.Member as ParameterExpression);
var selectMethod = MethodProvider.MakeGenericMethod(typeof(Enumerable), "Select",
new Type[] { typeof(IEnumerable <>), typeof(Func <,>) },
new Type[] { walkInfo.Type, walkInfo.Type });
return(Expression.Call(
selectMethod,
expression ?? walkInfo.DetailMember,
memberInitializationExpression));
}
private Expression BuildWhereExpression(OneToManyQueryDetailWalkInfo walkInfo)
{
var filterExpression = BuildFilterExpression(walkInfo);
if (filterExpression != null)
{
var whereMethod = MethodProvider.MakeGenericMethod(typeof(Enumerable), "Where",
new Type[] { typeof(IEnumerable <>), typeof(Func <,>) },
new Type[] { walkInfo.Type });
return(Expression.Call(
whereMethod,
walkInfo.DetailMember,
filterExpression));
}
return(null);
}