public static Expression <Func <TEntity, bool> > Parse <TEntity>(IDataFilter dataFilter, DataFilterMetaInfo filterInfo, Expression node)
{
ObjectChecker.CheckNotNull(filterInfo);
var filterFields = filterInfo.FilterFields;
if (filterFields.Count == 0)
{
return((Expression <Func <TEntity, bool> >)node);
}
// filter
var body = node;
foreach (var filterField in filterFields)
{
var handler = FilterFieldHandlerFactory.GetHandler(filterField.FilterFieldType);
if (handler != null)
{
// call FilterFieldHandler
body = handler.Handle(body, filterField);
}
}
// 删除 {True}
var optimizer = new ExprTreeOptimizer(body);
body = optimizer.Optimize();
return(body as Expression <Func <TEntity, bool> >);
}
public static Expression <Func <TEntity, bool> > Parse <TEntity>(IDataFilter dataFilter, DataFilterMetaInfo filterInfo, string paramName)
{
var body = Expression.Constant(true, typeof(bool));
var parameter = paramName.IsEmpty() ? PredicateBuilder.Paramter <TEntity>() : PredicateBuilder.Paramter <TEntity>(paramName);
var lambdaExpr = Expression.Lambda <Func <TEntity, bool> >(body, parameter);
return(Parse <TEntity>(dataFilter, filterInfo, lambdaExpr));
}