dotnet-dynamic-linq/PoweredSoft.DynamicLinq/Fluent/QueryBuilder.cs
2018-02-20 21:21:23 -06:00

115 lines
3.4 KiB
C#

using PoweredSoft.DynamicLinq.Helpers;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Text;
using System.Threading.Tasks;
namespace PoweredSoft.DynamicLinq.Fluent
{
public class QueryBuilder<T> : QueryBuilderBase
{
public IQueryable<T> Query { get; set; }
public Type QueryableType { get; set; }
public QueryBuilder(IQueryable<T> query)
{
Query = query;
}
public virtual IQueryable<T> Build()
{
// the query.
var query = Query;
// build the filters.
query = BuildFilters(query);
// build the sorts
query = BuildSorts(query);
return query;
}
protected virtual IQueryable<T> BuildSorts(IQueryable<T> query)
{
Sorts.ForEach(sort =>
{
query = QueryableHelpers.CreateSortExpression(query, sort.Path, sort.sortDirection, sort.AppendSort);
});
return query;
}
protected virtual IQueryable<T> BuildFilters(IQueryable<T> query)
{
if (Filters == null || Filters?.Count() == 0)
return query;
// shared parameter.
var sharedParameter = Expression.Parameter(typeof(T), "t");
// build the expression.
var filterExpressionMerged = BuildFilterExpression(sharedParameter, Filters);
// make changes on the query.
query = query.Where(filterExpressionMerged);
return query;
}
protected virtual Expression<Func<T, bool>> BuildFilterExpression(ParameterExpression parameter, List<QueryBuilderFilter> filters)
{
Expression<Func<T, bool>> temp = null;
filters.ForEach(filter =>
{
Expression<Func<T, bool>> innerExpression;
if (filter.Filters?.Any() == true)
innerExpression = BuildFilterExpression(parameter, filter.Filters);
else
innerExpression = BuildFilterExpression(parameter, filter);
if (temp == null)
{
temp = innerExpression;
}
else
{
if (filter.And)
temp = Expression.Lambda<Func<T, bool>>(Expression.AndAlso(temp.Body, innerExpression.Body), parameter);
else
temp = Expression.Lambda<Func<T, bool>>(Expression.OrElse(temp.Body, innerExpression.Body), parameter);
}
});
return temp;
}
protected virtual Expression<Func<T, bool>> BuildFilterExpression(ParameterExpression parameter, QueryBuilderFilter filter)
{
var ret = QueryableHelpers.CreateFilterExpression<T>(
filter.Path,
filter.ConditionOperator,
filter.Value,
filter.ConvertStrategy,
filter.CollectionHandling,
parameter: parameter,
nullChecking: IsNullCheckingEnabled
);
return ret;
}
protected override QueryBuilderBase GetSubQueryBuilder()
{
return new QueryBuilder<T>(Query);
}
}
}