public static Expression <Func <T, bool> > GetExpression <T>(
ParsedSearchString parsedSearchString,
string fieldName)
{
ParameterExpression param = Expression.Parameter(typeof(T));
var member = Expression.Property(param, fieldName);
//single expression
if (parsedSearchString.SecondPredicate == null)
{
var expression = ApplyOperator(parsedSearchString.FirstPredicate, member);
return(Expression.Lambda <Func <T, bool> >(expression, param));
}
//Two expressions
if (parsedSearchString.IsAndOperator)
{
BinaryExpression expression = Expression.AndAlso(
ApplyOperator(parsedSearchString.FirstPredicate, member),
ApplyOperator(parsedSearchString.SecondPredicate, member));
return(Expression.Lambda <Func <T, bool> >(expression, param));
}
else
{
BinaryExpression expression = Expression.OrElse(
ApplyOperator(parsedSearchString.FirstPredicate, member),
ApplyOperator(parsedSearchString.SecondPredicate, member));
return(Expression.Lambda <Func <T, bool> >(expression, param));
}
}
public IEnumerable <Notebook> SearchNotebooks(string searchString)
{
ParsedSearchString parsedSearchString = this._predicateParser.Parse(searchString);
return(this._context
.NotebookList
.Where(QueryObject.GetExpression <Notebook>(parsedSearchString, nameof(Notebook.Name))));
}
