title: LINQ to XML in C# where clause
body: <p>I`ve got a piece in xml:</p>
  
  <pre><code>&lt;result index="0" status="0"&gt;
            &lt;test field="aaa"&gt;value_a&lt;/test&gt;
            &lt;test field="bbb"&gt;value_b&lt;/test&gt;
            &lt;one&gt;
              &lt;name&gt;&lt;/name&gt;
              &lt;res1&gt;&lt;/res1&gt;
            &lt;/one&gt;
            &lt;two&gt;
              &lt;name&gt;&lt;/name&gt;
              &lt;res2&gt;&lt;/res2&gt;
            &lt;/two&gt;
            &lt;answer&gt;&lt;/answer&gt;
            &lt;error&gt;&lt;/error&gt;
          &lt;/result&gt;
  
  var rez = from item in doc.Descendants("result")
                            where 
  
  
                            select item;
  
                  foreach (var item in rez)
                  {
                      item.Element("res1").SetValue(x);
                      item.Element("res2").SetValue(y);
                  }
  </code></pre>
  
  <p>What do i write inside "where" to select an item ("result" block) where element "test" with attribute "aaa" has value_a, AND element "test" with an attribute "bbb" has value_b</p>