/// <summary>
/// Applies the <see cref="DataTablesRequest{TEntity, TEntityViewModel}.GlobalSearchValue"/> of the given
/// <see cref="IDataTablesQueryable{TEntity, TEntityViewModel}"/> to the query, if set.
/// To perform the global search, the method will add a search expression for each searchable column of the request.
/// </summary>
/// <typeparam name="TEntity">The type of the entity.</typeparam>
/// <typeparam name="TEntityViewModel">The type of the entity view model.</typeparam>
/// <param name="queryable">The queryable.</param>
public static IDataTablesQueryable <TEntity, TEntityViewModel> ApplyGlobalSearchFilter <TEntity, TEntityViewModel>(
this IDataTablesQueryable <TEntity, TEntityViewModel> queryable)
{
var globalSearchValue = queryable.Request.GlobalSearchValue;
if (!string.IsNullOrEmpty(globalSearchValue))
{
var columns = queryable.Request.Columns.Where(c => c.IsSearchable);
if (columns.Any())
{
Expression <Func <TEntity, bool> > predicate = null;
foreach (var c in columns)
{
Expression <Func <TEntity, bool> > expression;
var searchPredicate = c.GlobalSearchPredicate ?? c.SearchPredicate;
if (searchPredicate != null)
{
var expr = searchPredicate;
var entityParam = expr.Parameters.Single(p => p.Type == typeof(TEntity));
var searchValueConstant = Expression.Constant(globalSearchValue);
expression = (Expression <Func <TEntity, bool> >)Expression.Lambda(Expression.Invoke(expr, entityParam, searchValueConstant), entityParam);
}
else
{
if (queryable.Request.GlobalSearchRegex)
{
expression = ExpressionHelper.BuildRegexPredicate <TEntity>(c.PrivatePropertyName, globalSearchValue);
}
else
{
expression = ExpressionHelper.BuildStringContainsPredicate <TEntity>(c.PrivatePropertyName, globalSearchValue, c.SearchCaseInsensitive);
}
}
predicate = predicate == null
? PredicateBuilder.Create(expression)
: predicate.Or(expression);
}
queryable = (IDataTablesQueryable <TEntity, TEntityViewModel>)queryable.Where(predicate);
}
}
return(queryable);
}