public ConditionItem(NodeBlock propertys, QueryComparison comparison, NodeBlock value, Type typeAs) : this()
 {
     _propertyBlock = propertys;
     _ValueBlock    = value;
     TypeAs         = typeAs;
     Comparison     = comparison;
 }
 /// <summary>
 /// 查询参数,令 typeAs 默认=null,即与value 的 type 相同.
 /// </summary>
 /// <param name="name">属性名(字段名)</param>
 /// <param name="comparsionStr">比较符</param>
 /// <param name="value">查询条件值</param>
 public ConditionItem(string name, string comparsionStr, NodeBlock value)
     : this(name, GetComparisonWithString(comparsionStr), value, null)
 {
 }
 /// <summary>
 /// 查询条件
 /// </summary>
 /// <param name="name">属性名(字段名)</param>
 /// <param name="comparison">比较符</param>
 /// <param name="value">查询条件值</param>
 /// <param name="typeAs">字段的强制数据类型. typeAs 默认=null,即与value 的 type 相同.</param>
 public ConditionItem(string name, QueryComparison comparison, NodeBlock value, Type typeAs)
     : this(SetPropertyBlock(name), comparison, value, typeAs)
 {
 }
 public ConditionItem(ValueItem property, QueryComparison comparison, NodeBlock value, Type typeAs)
     : this(SetPropertyBlock(property), comparison, value, typeAs)
 {
 }
 public ConditionItem(NodeBlock propertys, QueryComparison comparison, object value, Type typeAs)
     : this(propertys, comparison, SetValueBlock(value), typeAs)
 {
 }