Radarr/NzbDrone.Core/Datastore/PagingSpecExtensions.cs

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2013-05-07 02:32:43 +00:00
using System;
using System.Linq;
using System.Linq.Expressions;
namespace NzbDrone.Core.Datastore
{
public static class PagingSpecExtensions
{
public static Expression<Func<TModel, object>> OrderByClause<TModel>(this PagingSpec<TModel> pagingSpec)
{
return CreateExpression<TModel>(pagingSpec.SortKey);
}
public static int PagingOffset<TModel>(this PagingSpec<TModel> pagingSpec)
{
return (pagingSpec.Page - 1)*pagingSpec.PageSize;
}
public static Marr.Data.QGen.SortDirection ToSortDirection<TModel>(this PagingSpec<TModel> pagingSpec)
{
if (pagingSpec.SortDirection == SortDirection.Descending) return Marr.Data.QGen.SortDirection.Desc;
return Marr.Data.QGen.SortDirection.Asc;
}
2013-05-07 02:32:43 +00:00
private static Expression<Func<TModel, object>> CreateExpression<TModel>(string propertyName)
{
Type type = typeof(TModel);
ParameterExpression parameterExpression = Expression.Parameter(type, "x");
Expression expressionBody = parameterExpression;
var splitPropertyName = propertyName.Split('.').ToList();
foreach (var property in splitPropertyName)
{
expressionBody = Expression.Property(expressionBody, property);
}
expressionBody = Expression.Convert(expressionBody, typeof(object));
return Expression.Lambda<Func<TModel, object>>(expressionBody, parameterExpression);
}
}
}