public void Build(EntityFilter entityFilter)
{
_expression.Length = 0;
_values.Clear();
if (entityFilter == null)
{
return;
}
Visit(entityFilter);
}
public static IQueryable <T> Filter <T>(this IQueryable <T> query, EntityFilter filter)
{
if (filter == null)
{
return(query);
}
var builder = new LinqExpressionBuilder();
builder.Build(filter);
var predicate = builder.Expression;
var parameters = builder.Parameters.ToArray();
if (string.IsNullOrWhiteSpace(predicate))
{
return(query);
}
return(query.Where(predicate, parameters));
}
private bool WriteGroup(EntityFilter entityFilter)
{
var hasGroup = entityFilter.Filters != null && entityFilter.Filters.Any();
if (!hasGroup)
{
return(false);
}
if (!string.IsNullOrWhiteSpace(entityFilter.Name))
{
var logic = string.IsNullOrWhiteSpace(entityFilter.Logic)
? EntityFilterLogic.And
: entityFilter.Logic;
_expression.Append($" {logic} (");
}
else
{
_expression.Append("(");
}
foreach (var filter in entityFilter.Filters)
{
Visit(filter);
var isLast = entityFilter.Filters.LastOrDefault() == filter;
if (filter == null)
{
continue;
}
var filterLogic = string.IsNullOrWhiteSpace(filter.Logic)
? EntityFilterLogic.And
: filter.Logic;
if (!isLast)
{
_expression.Append($" {filterLogic} ");
}
}
_expression.Append(")");
return(true);
}
private void WriteExpression(EntityFilter entityFilter)
{
if (string.IsNullOrWhiteSpace(entityFilter.Name))
{
return;
}
var index = _values.Count;
var name = entityFilter.Name;
var value = entityFilter.Value;
var o = string.IsNullOrWhiteSpace(entityFilter.Operator) ? "==" : entityFilter.Operator;
_operatorMap.TryGetValue(o, out string comparison);
if (string.IsNullOrEmpty(comparison))
{
comparison = o.Trim();
}
var negation = comparison.StartsWith("!") || comparison.StartsWith("not", StringComparison.OrdinalIgnoreCase) ? "!" : string.Empty;
if (comparison.EndsWith(EntityFilterOperators.StartsWith, StringComparison.OrdinalIgnoreCase))
{
_expression.Append($"{negation}{name}.StartsWith(@{index})");
}
else if (comparison.EndsWith(EntityFilterOperators.EndsWith, StringComparison.OrdinalIgnoreCase))
{
_expression.Append($"{negation}{name}.EndsWith(@{index})");
}
else if (comparison.EndsWith(EntityFilterOperators.Contains, StringComparison.OrdinalIgnoreCase))
{
_expression.Append($"{negation}{name}.Contains(@{index})");
}
else
{
_expression.Append($"{name} {comparison} @{index}");
}
_values.Add(value);
}
public EntityListQuery(EntityFilter filter, IEnumerable <EntitySort> sort)
{
Filter = filter;
Sort = sort;
}
public EntityListQuery(EntityFilter filter, string includeProperties)
: this(filter, (IEnumerable <EntitySort>)null)
{
this.IncludeProperties = includeProperties;
}
public EntityListQuery(EntityFilter filter, EntitySort sort)
: this(filter, new[] { sort })
{
}
public EntityListQuery(EntityFilter filter)
: this(filter, (IEnumerable <EntitySort>)null)
{
}
private void Visit(EntityFilter entityFilter)
{
WriteExpression(entityFilter);
WriteGroup(entityFilter);
}