private static Expression BuildExpressionTree(ParameterExpression pe, FilterRule rule, bool useIndexedProperty = false, string indexedPropertyName = null)
{
if (rule.Rules != null && rule.Rules.Any())
{
var expressions =
rule.Rules.Select(childRule => BuildExpressionTree(pe, childRule, useIndexedProperty, indexedPropertyName))
.Where(expression => expression != null)
.ToList();
var expressionTree = expressions.First();
var counter = 1;
while (counter < expressions.Count)
{
expressionTree = rule.Condition.ToLower() == "or"
? Expression.Or(expressionTree, expressions[counter])
: Expression.And(expressionTree, expressions[counter]);
counter++;
}
return(expressionTree);
}
if (rule.Field != null)
{
Type type;
switch (rule.Type)
{
case "integer":
type = typeof(int);
break;
case "double":
type = typeof(double);
break;
case "string":
type = typeof(string);
break;
case "date":
case "datetime":
type = typeof(DateTime);
break;
case "boolean":
type = typeof(bool);
break;
default:
throw new Exception($"Unexpected data type {rule.Type}");
}
Expression propertyExp = null;
if (useIndexedProperty)
{
propertyExp = Expression.Property(pe, indexedPropertyName, Expression.Constant(rule.Field));
}
else
{
propertyExp = Expression.Property(pe, rule.Field);
}
Expression expression;
switch (rule.Operator.ToLower())
{
case "in":
expression = In(type, rule.Value, propertyExp);
break;
case "not_in":
expression = NotIn(type, rule.Value, propertyExp);
break;
case "equal":
expression = Equals(type, rule.Value, propertyExp);
break;
case "not_equal":
expression = NotEquals(type, rule.Value, propertyExp);
break;
case "between":
expression = Between(type, rule.Value, propertyExp);
break;
case "not_between":
expression = NotBetween(type, rule.Value, propertyExp);
break;
case "less":
expression = LessThan(type, rule.Value, propertyExp);
break;
case "less_or_equal":
expression = LessThanOrEqual(type, rule.Value, propertyExp);
break;
case "greater":
expression = GreaterThan(type, rule.Value, propertyExp);
break;
case "greater_or_equal":
expression = GreaterThanOrEqual(type, rule.Value, propertyExp);
break;
case "begins_with":
expression = BeginsWith(type, rule.Value, propertyExp);
break;
case "not_begins_with":
expression = NotBeginsWith(type, rule.Value, propertyExp);
break;
case "contains":
expression = Contains(type, rule.Value, propertyExp);
break;
case "not_contains":
expression = NotContains(type, rule.Value, propertyExp);
break;
case "ends_with":
expression = EndsWith(type, rule.Value, propertyExp);
break;
case "not_ends_with":
expression = NotEndsWith(type, rule.Value, propertyExp);
break;
case "is_empty":
expression = IsEmpty(propertyExp);
break;
case "is_not_empty":
expression = IsNotEmpty(propertyExp);
break;
case "is_null":
expression = IsNull(propertyExp);
break;
case "is_not_null":
expression = IsNotNull(propertyExp);
break;
default:
throw new Exception($"Unknown expression operator: {rule.Operator}");
}
return(expression);
}
return(null);
}
/// <summary>
/// Gets the filtered collection after applying the provided filter rules.
/// </summary>
/// <typeparam name="T">The generic type.</typeparam>
/// <param name="queryable">The queryable.</param>
/// <param name="filterRule">The filter rule.</param>
/// <param name="useIndexedProperty">Whether or not to use indexed property</param>
/// <param name="indexedPropertyName">The indexable property to use</param>
/// <returns>Filtered IQueryable</returns>
public static IQueryable <T> BuildQuery <T>(this IQueryable <T> queryable, FilterRule filterRule, bool useIndexedProperty = false, string indexedPropertyName = null)
{
string parsedQuery;
return(BuildQuery(queryable, filterRule, out parsedQuery, useIndexedProperty, indexedPropertyName));
}
/// <summary>
/// Gets the filtered collection after applying the provided filter rules.
/// </summary>
/// <typeparam name="T">The generic type.</typeparam>
/// <param name="queryable">The queryable.</param>
/// <param name="filterRule">The filter rule.</param>
/// <returns>Filtered IQueryable</returns>
public static IQueryable <T> BuildQuery <T>(this IQueryable <T> queryable, FilterRule filterRule)
{
string parsedQuery;
return(BuildQuery(queryable, filterRule, out parsedQuery));
}
/// <summary>
/// Gets the filtered collection after applying the provided filter rules.
/// Returns the string representation for diagnostic purposes.
/// </summary>
/// <typeparam name="T">The generic type.</typeparam>
/// <param name="queryable">The queryable.</param>
/// <param name="filterRule">The filter rule.</param>
/// <param name="parsedQuery">The parsed query.</param>
/// <param name="useIndexedProperty">Whether or not to use indexed property</param>
/// <param name="indexedPropertyName">The indexable property to use</param>
/// <returns>Filtered IQueryable.</returns>
public static IQueryable <T> BuildQuery <T>(this IQueryable <T> queryable, FilterRule filterRule, out string parsedQuery, bool useIndexedProperty = false, string indexedPropertyName = null)
{
return(BuildQuery(queryable, filterRule, new BuildExpressionOptions {
UseIndexedProperty = useIndexedProperty, IndexedPropertyName = indexedPropertyName
}, out parsedQuery));
}
/// <summary>
/// Builds a predicate that returns whether an input test object passes the filter rule.
/// </summary>
/// <typeparam name="T">The generic type of the input object to test.</typeparam>
/// <param name="filterRule">The filter rule.</param>
/// <param name="options">The options to use when building the expression</param>
/// <returns>A predicate function implementing the filter rule</returns>
public static Func <T, bool> BuildPredicate <T>(this FilterRule filterRule, BuildExpressionOptions options)
{
string parsedQuery;
return(BuildPredicate <T>(filterRule, options, out parsedQuery));
}
/// <summary>
/// Gets the filtered collection after applying the provided filter rules.
/// Returns the string representation for diagnostic purposes.
/// </summary>
/// <typeparam name="T">The generic type.</typeparam>
/// <param name="queryable">The queryable.</param>
/// <param name="filterRule">The filter rule.</param>
/// <param name="options">The options to use when building the expression</param>
/// <returns>Filtered IQueryable.</returns>
public static IQueryable <T> BuildQuery <T>(this IQueryable <T> queryable, FilterRule filterRule, BuildExpressionOptions options)
{
string parsedQuery;
return(BuildQuery(queryable, filterRule, options, out parsedQuery));
}
/// <summary>
/// Gets the filtered collection after applying the provided filter rules.
/// </summary>
/// <typeparam name="T">The generic type.</typeparam>
/// <param name="queryable">The queryable.</param>
/// <param name="filterRule">The filter rule.</param>
/// <param name="useIndexedProperty">Whether or not to use indexed property</param>
/// <param name="indexedPropertyName">The indexable property to use</param>
/// <returns>Filtered IQueryable</returns>
public static Expression <Func <T, bool> > BuildQueryExpression <T>(FilterRule filterRule, bool useIndexedProperty = false, string indexedPropertyName = null)
{
return(BuildExpression <T>(filterRule, useIndexedProperty, indexedPropertyName));
}