Linq to XML没有值

Question

I just can't seem to figure out whats wrong with this code... Any idea's what I'm doing wrong. The select returns one item, with all null attributes, ie the foreach loop gets entered once and the WMServer Server.[pick attribute] is set to null.

var xdoc = XDocument.Load(@"pathtoxmlfile.xml");
var wms = from e2 in xdoc.Elements("GISImportConfig").Elements("BaseMapLayers")
          select new
          {
              Url = (string)e2.Attribute("url"),
              Enabled = (string)e2.Attribute("enabled"),
              UserName = (string)e2.Attribute("username"),
              Pasword = (string)e2.Attribute("password"),
              Layers = e2.Elements("WMLayer")
          };

foreach (var Config in wms)
{
    WMServer server = new WMServer();
    server.ServerURL = Config.Url;
    server.Enabled = Convert.ToBoolean(Config.Enabled);
    server.UserName = Config.UserName;
    server.Password = Config.Pasword;

    foreach (var layers in Config.Layers)
    {
        WMLayer layer = new WMLayer();
        layer.Group = (string)layers.Attribute("group");
        layer.Enabled = Convert.ToBoolean(layers.Attribute("enabled"));
        layer.Name = (string)layers.Attribute("name");
    }
}

xml:

<?xml version="1.0" encoding="utf-8" ?>
<GISImportConfig OracleServer="*" OracleInstance="*"   OracleSchema="*">
  <BaseMapLayers>
    <WMServer  url="https://example" enabled="true" username="someuser" password="somepass">
      <WMLayer name="0" enabled ="true" group="test"></WMLayer>
      <WMLayer name="1" enabled ="true" group="test"></WMLayer>
    </WMServer>
    <WMServer url="server2" enabled="false" username="" password="">
      <WMLayer name="test2" enabled ="true" group="test"></WMLayer>
    </WMServer>
  </BaseMapLayers>
</GISImportConfig>

Answer 1

You get only one result, because you have only one <BaseMapLayers> element, and that's the one you're looking for with your query. Add .Elements("WMServer") method call and it should work:

from e2 in xdoc.Elements("GISImportConfig").Elements("BaseMapLayers").Elements("WMServer")
select new
{
    Url = (string)e2.Attribute("url"),
    Enabled = (string)e2.Attribute("enabled"),
    UserName = (string)e2.Attribute("username"),
    Pasword = (string)e2.Attribute("password"),
    Layers = e2.Elements("WMLayer")
};

Returns 2 elements with non-null attribute values.

Answer 2

It looks like you're trying to get the WMServer elements and you're currently selecting the BaseMapLayers element (of which only one exists).

You could get the WMServer elements by doing this:

from e2 in xdoc.Descendants("WMServer")
select new
{
      Url = (string)e2.Attribute("url"),
      Enabled = (string)e2.Attribute("enabled"),
      UserName = (string)e2.Attribute("username"),
      Pasword = (string)e2.Attribute("password"),
      Layers = e2.Elements("WMLayer")
};

which will grab you all the WMServer descendent elements.

I think MarcinJuraszek has a better answer (appending the relevant element), as there's less scope to run into problems if you find a misplaced WMServer element, or only want those at that specific location in the xml.