private IOrderedQueryable <TEntity> ApplyOrderBy <TKey>(IQueryable <TEntity> query, Expression <Func <TEntity, TKey> > expr, SortColumn.Directions direction)
{
switch (direction)
{
case SortColumn.Directions.Ascending:
return(query.OrderBy(expr));
case SortColumn.Directions.Descending:
return(query.OrderByDescending(expr));
default:
throw new ArgumentOutOfRangeException();
}
}
private IOrderedQueryable <TEntity> StrongTypeOrderBy(Expression <Func <TEntity, object> > orderByExpression, IOrderedQueryable <TEntity>?orderedQuery, IQueryable <TEntity> query, SortColumn.Directions direction)
{
var exprbody = orderByExpression.Body;
if (exprbody.NodeType == ExpressionType.Convert)
{
exprbody = ((UnaryExpression)exprbody).Operand;
}
var expressionAsLambda = Expression.Lambda(exprbody, orderByExpression.Parameters);
if (exprbody.Type == typeof(Guid))
{
var asexpression = (Expression <Func <TEntity, Guid> >)expressionAsLambda;
orderedQuery = orderedQuery == null
? ApplyOrderBy(query, asexpression, direction)
: ApplyThenBy(orderedQuery, asexpression, direction);
}
else if (exprbody.Type == typeof(DateTime))
{
var asexpression = (Expression <Func <TEntity, DateTime> >)expressionAsLambda;
orderedQuery = orderedQuery == null
? ApplyOrderBy(query, asexpression, direction)
: ApplyThenBy(orderedQuery, asexpression, direction);
}
else if (exprbody.Type == typeof(int))
{
var asexpression = (Expression <Func <TEntity, int> >)expressionAsLambda;
orderedQuery = orderedQuery == null
? ApplyOrderBy(query, asexpression, direction)
: ApplyThenBy(orderedQuery, asexpression, direction);
}
else if (exprbody.Type == typeof(string))
{
var asexpression = (Expression <Func <TEntity, string> >)expressionAsLambda;
orderedQuery = orderedQuery == null
? ApplyOrderBy(query, asexpression, direction)
: ApplyThenBy(orderedQuery, asexpression, direction);
}
else
{
throw new ArgumentOutOfRangeException();
}
return(orderedQuery);
}
