protected override Expression VisitBinary(BinaryExpression node)
{
BooleanClause clause;
if (ClauseMapping.TryGetValue(node.NodeType, out clause))
{
var leftVisitor = new SimpleVisitor();
leftVisitor.Visit(node.Left);
var rightVisitor = new SimpleVisitor();
rightVisitor.Visit(node.Right);
_filter = new CombinedQueryFilter(leftVisitor._filter, rightVisitor._filter, clause);
return(node);
}
BinaryOperation symbol;
if (OperationMapping.TryGetValue(node.NodeType, out symbol))
{
var leftVisitor = new SimpleVisitor();
leftVisitor.Visit(node.Left);
var rightVisitor = new SimpleVisitor();
rightVisitor.Visit(node.Right);
var x = new SingleQueryFilter();
x.AddPredicate(leftVisitor._fieldName, symbol, rightVisitor._value);
_filter = x;
return(node);
}
throw new NotSupportedException($"不支将 Lamda 表达式解析为 {nameof(QueryFilter)}，请确保右侧的表达式是一个符合规范的二元表达式。");
}
private string GenerateSingleFilter <TEntity>(SingleQueryFilter queryFilter, DynamicParameters parameters)
{
if (queryFilter.IsEmpty)
{
return(String.Empty);
}
string spliter = queryFilter.Clause == BooleanClause.Or ? " OR " : " AND ";
return(queryFilter.Select(p => GeneratePredicateFilter <TEntity>(p, parameters)).ToArray().ToArrayString(spliter));
}
/// <summary>
/// 生成查询过滤。
/// </summary>
/// <param name="queryFilter">查询过来器实例。</param>
/// <param name="parameters">查询参数</param>
/// <returns></returns>
public String GenerateFilter <TEntity>(QueryFilter queryFilter, DynamicParameters parameters)
{
if (queryFilter != null)
{
SingleQueryFilter sqf = queryFilter as SingleQueryFilter;
if (sqf != null)
{
return(this.GenerateSingleFilter <TEntity>(sqf, parameters));
}
CombinedQueryFilter cqf = queryFilter as CombinedQueryFilter;
if (cqf != null)
{
return(GenerateCombinedFilter <TEntity>(cqf, parameters));
}
}
return(null);
}
public Task <IEnumerable <T> > QueryAsync <TField>(string fieldName, IEnumerable <TField> fieldValues)
{
Guard.ArgumentNullOrWhiteSpaceString(fieldName, nameof(fieldName));
if (fieldValues.IsNullOrEmpty())
{
return(Task.FromResult(Enumerable.Empty <T>()));
}
if (fieldValues.Count() == 1)
{
SingleQueryFilter filter = new SingleQueryFilter();
filter.AddEqual(fieldName, fieldValues.First());
return(this.QueryAsync(filter));
}
else
{
var sql = GenerateQueryInSql(fieldName, fieldValues.Cast <Object>());
var connection = this.GetReadingConnection();
return(connection.QueryAsync <T>(sql.Sql, sql.Parameters));
}
}