/// <summary>
/// Returns a list of distinct column values that can be used for select filters.
/// </summary>
/// <param name="column">The column.</param>
public virtual IList <string> GetDistinctColumnValues(DataTablesColumn <TEntity, TEntityViewModel> column)
{
var parameterExp = ExpressionHelper.BuildParameterExpression <TEntity>();
var propertyExp = ExpressionHelper.BuildPropertyExpression(parameterExp, column.PrivatePropertyName);
var stringExp = Expression.Call(propertyExp, ExpressionHelper.Object_ToString);
var lambda = Expression.Lambda <Func <TEntity, string> >(stringExp, parameterExp);
return(GetDistinctColumnValues(lambda));
}
/// <summary>
/// Orders the given <see cref="IQueryable{TEntity}"/> by the given <paramref name="propertyName"/>.
/// The method will consider the given <paramref name="direction"/> and if the order should be applied
/// with <paramref name="caseInsensitive"/> logic.
/// </summary>
/// <typeparam name="TEntity">The type of the entity.</typeparam>
/// <param name="query">The query.</param>
/// <param name="propertyName">Name of the property.</param>
/// <param name="direction">The direction.</param>
/// <param name="caseInsensitive">if set to <c>true</c>, the order logic is case insensitive.</param>
/// <param name="alreadyOrdered">if set to <c>true</c>, follow-up order logic will be used.</param>
internal static IQueryable <TEntity> OrderBy <TEntity>(this IQueryable <TEntity> query,
string propertyName, ListSortDirection direction, bool caseInsensitive, bool alreadyOrdered)
{
var type = typeof(TEntity);
var parameterExp = Expression.Parameter(type, "e");
var propertyExp = ExpressionHelper.BuildPropertyExpression(parameterExp, propertyName);
Expression exp = propertyExp;
if (caseInsensitive && propertyExp.Type == typeof(string))
{
exp = Expression.Call(exp, ExpressionHelper.String_ToLower);
}
var methodName = GetOrderMethodName(direction, alreadyOrdered);
var orderByExp = Expression.Lambda(exp, parameterExp);
var typeArguments = new Type[] { type, propertyExp.Type };
var resultExpr = Expression.Call(typeof(Queryable), methodName, typeArguments, query.Expression, Expression.Quote(orderByExp));
return(query.Provider.CreateQuery <TEntity>(resultExpr));
}
