C# 按属性值选择节点

我有一个如下所示的XML：

    <TRANSFORMATION DESCRIPTION ="" NAME ="RTR_LRC_RF_REFL_Unproc" OBJECTVERSION ="1" REUSABLE ="NO" TYPE ="Router" VERSIONNUMBER ="1">
              <GROUP DESCRIPTION ="" NAME ="INPUT" ORDER ="1" TYPE ="INPUT"/>
              <GROUP DESCRIPTION ="" EXPRESSION ="EXP 1" NAME ="Good" ORDER ="2" TYPE ="OUTPUT"/>
              <GROUP DESCRIPTION ="Path for the data when none of the group conditions are satisfied." NAME ="DEFAULT1" ORDER ="3" TYPE ="OUTPUT/DEFAULT"/>
              <TRANSFORMFIELD DATATYPE ="integer" DEFAULTVALUE ="" DESCRIPTION ="" GROUP ="INPUT" NAME ="OWNER_HEORG_REFNO" PICTURETEXT ="" PORTTYPE ="INPUT" PRECISION ="10" SCALE ="0"/>
              <TRANSFORMFIELD DATATYPE ="integer" DEFAULTVALUE ="" DESCRIPTION ="" GROUP ="INPUT" NAME ="PATNT_REFNO" PICTURETEXT ="" PORTTYPE ="INPUT" PRECISION ="10" SCALE ="0"/>
              <TRANSFORMFIELD DATATYPE ="integer" DEFAULTVALUE ="" DESCRIPTION ="" GROUP ="INPUT" NAME ="REFRL_REFNO" PICTURETEXT ="" PORTTYPE ="INPUT" PRECISION ="10" SCALE ="0"/>
==============================================================================================
<GROUP DESCRIPTION ="" EXPRESSION ="(Valid_Record_Flag = &apos;Y&apos; 
<GROUP DESCRIPTION ="Path for the data when none of the group condition
<GROUP DESCRIPTION ="" EXPRESSION ="EXP2" .../> 
<GROUP DESCRIPTION ="" EXPRESSION ="EXP3" .../> 
<GROUP DESCRIPTION ="" EXPRESSION ="EXP4" .../> 

但这会使所有TRANSFORMFIELD节点（包括组节点）的表达式属性只出现一次

如果组节点的EXPRESSION属性多次出现，如何获取TRANSFORMFIELD节点

---

非常感谢

我不能百分之百确定我是否理解您的要求，但我认为您只想获得

转换

的所有

转换字段

，其中包含多个定义了

表达式的
组
元素。您可以这样做：

var query =
    from transform in doc.Descendants("TRANSFORMATION")
    where String.Equals((string)transform.Attribute("TYPE"), "router",
                        StringComparison.OrdinalIgnoreCase)
    // GROUP elements that have more than one EXPRESSIONs defined
    where transform.Elements("GROUP")
                   .Where(e => e.Attribute("EXPRESSION") != null)
                   .Skip(1).Any() // more than one
    select transform.Elements("TRANSFORMFIELD");

var query =
    from transform in doc.Descendants("TRANSFORMATION")
    where String.Equals((string)transform.Attribute("TYPE"), "router",
                        StringComparison.OrdinalIgnoreCase)
    // GROUP elements that have more than one EXPRESSIONs defined
    where transform.Elements("GROUP")
                   .Where(e => e.Attribute("EXPRESSION") != null)
                   .Skip(1).Any() // more than one
    select transform.Elements("TRANSFORMFIELD");