{"id":2853,"date":"2009-04-29T20:20:00","date_gmt":"2009-04-29T20:20:00","guid":{"rendered":"https:\/\/blogs.msdn.microsoft.com\/vbteam\/2009\/04\/29\/when-using-linq-to-xml-why-dont-i-get-results-if-i-dont-import-a-xml-namespace-daniel-walzenbach\/"},"modified":"2024-07-05T13:20:50","modified_gmt":"2024-07-05T20:20:50","slug":"when-using-linq-to-xml-why-dont-i-get-results-if-i-dont-import-a-xml-namespace-daniel-walzenbach","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/vbteam\/when-using-linq-to-xml-why-dont-i-get-results-if-i-dont-import-a-xml-namespace-daniel-walzenbach\/","title":{"rendered":"When using LINQ to XML why don’t I get results if I don’t import a XML namespace (Daniel Walzenbach)?"},"content":{"rendered":"

Hi,<\/p>\n

I posted a bit of code<\/a> the other day which I used to get a list of all Code Snippets<\/a> we ship in Visual Studio<\/a>. In a nutshell, I used XElement.Load<\/a> to create a new XML document from a filename from which I then read elements from (There are way to many ‘”from” in this sentence \ud83d\ude09 ). Unfortunately, I forgot to import the XML Namespace<\/a> in the code I posted which caused my code not to return any results (but instead provided me with a brilliant opportunity to write another post. hehe \ud83d\ude42 ).<\/p>\n

Let’s have a look at the code which is causing trouble and a Code Snippets to understand what’s going on (you can find the complete code including the Snippet <\/em>class in the aforementioned post<\/a>):<\/p>\n\n\n\n
\n

Dim<\/span> query = _<\/span><\/p>\n

    <\/span>From<\/span> file In<\/span> My<\/span>.Computer.FileSystem.GetFiles( _<\/span><\/p>\n

        <\/span>“C:Program FilesMicrosoft Visual Studio 10.0”<\/span>, _<\/span><\/p>\n

        <\/span>FileIO.SearchOption.SearchAllSubDirectories) _<\/span><\/p>\n

    <\/span>Where<\/span> file.EndsWith(“.snippet”<\/span>) _<\/span><\/p>\n

    <\/span>Order<\/span> By<\/span> file<\/span><\/p>\n

<\/span><\/p>\n

 <\/p>\n

 <\/p>\n

Dim<\/span> snippets As<\/span> New<\/span> List(Of<\/span> Snippet)<\/span><\/p>\n

Dim<\/span> snippetDocument As<\/span> XElement<\/span><\/p>\n

Dim<\/span> snippet As<\/span> Snippet<\/span><\/p>\n

<\/span><\/p>\n

 <\/p>\n

 <\/p>\n

For<\/span> Each<\/span> item In<\/span> query<\/span><\/p>\n

    <\/span>snippetDocument = XElement.Load(item)<\/span><\/p>\n

    <\/span>If<\/span> snippetDocument…<<\/span>Title><\/span>.Value IsNot<\/span> Nothing<\/span> Then<\/span><\/span><\/p>\n

<\/span><\/p>\n

 <\/p>\n

 <\/p>\n

        <\/span>snippet = New<\/span> Snippet With<\/span> {.Title = snippetDocument…<<\/span>Title><\/span>.Value.ToString _<\/span><\/p>\n

                                    <\/span>, .Description = snippetDocument…<<\/span>Description><\/span>.Value.ToString _<\/span><\/p>\n

  <\/span>                                  <\/span>, .Path = item _<\/span><\/p>\n

                                    <\/span>, .Size = New<\/span> System.IO.FileInfo(item).Length}<\/span><\/p>\n

        <\/span>snippets.Add(snippet)<\/span><\/p>\n

    <\/span>End<\/span> If<\/span><\/span><\/p>\n

Next<\/span><\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

  Code Snippet<\/p>\n\n\n\n
\n

<?<\/span>xml<\/span> <\/span>version<\/span>=<\/span>“1.0<\/span>“ <\/span>encoding<\/span>=<\/span>“utf-8<\/span>“?><\/span><\/span><\/p>\n

<<\/span>CodeSnippets<\/span> <\/span>xmlns<\/span>=<\/span>“http:\/\/schemas.microsoft.com\/VisualStudio\/2005\/CodeSnippet<\/span>“><\/span><\/span><\/p>\n

  <\/span><<\/span>CodeSnippet<\/span> <\/span>Format<\/span>=<\/span>“1.0.0<\/span>“><\/span><\/span><\/p>\n

    <\/span><<\/span>Header<\/span>><\/span><\/p>\n

      <\/span><<\/span>Title<\/span>><\/span>Activate a Running Application by Name<\/<\/span>Title<\/span>><\/span><\/span><\/p>\n

      <\/span><<\/span>Author<\/span>><\/span>Microsoft Corporation<\/<\/span>Author<\/span>><\/span><\/span><\/p>\n

      <\/span><<\/span>Description<\/span>><\/span>Activates a running application using the name of the application.<\/<\/span>Description<\/span>><\/span><\/span><\/p>\n

      <\/span><<\/span>Shortcut<\/span>><\/span>appActNa<\/<\/span>Shortcut<\/span>><\/span><\/span><\/p>\n

    <\/span><\/<\/span>Header<\/span>><\/span><\/p>\n

    <\/span><<\/span>Snippet<\/span>><\/span><\/p>\n

      <\/span><<\/span>Imports<\/span>><\/span><\/p>\n

        <\/span><<\/span>Import<\/span>><\/span><\/p>\n

          <\/span><<\/span>Namespace<\/span>><\/span>Microsoft.VisualBasic<\/<\/span>Namespace<\/span>><\/span><\/span><\/p>\n

        <\/span><\/<\/span>Import<\/span>><\/span><\/p>\n

      <\/span><\/<\/span>Imports<\/span>><\/span><\/p>\n

      <\/span><<\/span>Declarations<\/span>><\/span><\/p>\n

        <\/span><<\/span>Literal<\/span>><\/span><\/p>\n

          <\/span><<\/span>ID<\/span>><\/span>applicationName<\/<\/span>ID<\/span>><\/span><\/span><\/p>\n

          <\/span><<\/span>Type<\/span>><\/span>String<\/<\/span>Type<\/span>><\/span><\/span><\/p>\n

          <\/span><<\/span>ToolTip<\/span>><\/span>Replace with the name of the application. This is often the title of the application window.<\/<\/span>ToolTip<\/span>><\/span><\/span><\/p>\n

          <\/span><<\/span>Default<\/span>><\/span>“Untitled – Notepad”<\/<\/span>Default<\/span>><\/span><\/span><\/p>\n

        <\/span><\/<\/span>Literal<\/span>><\/span><\/p>\n

      <\/span><\/<\/span>Declarations<\/span>><\/span><\/p>\n

      <\/span><<\/span>Code<\/span> <\/span>Language<\/span>=<\/span>“VB<\/span>“ <\/span>Kind<\/span>=<\/span>“method body<\/span>“><![CDATA[<\/span>AppActivate($applicationName$)<\/span>]]><\/<\/span>Code<\/span>><\/span><\/span><\/p>\n

    <\/span><\/<\/span>Snippet<\/span>><\/span><\/p>\n

  <\/span><\/<\/span>CodeSnippet<\/span>><\/span><\/p>\n

<\/<\/span>CodeSnippets<\/span>><\/span><\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

As you can see there is a <<\/span>Title<\/span>><\/span> element in the the Code Snippet to which we are referring to in the code above… or are we?<\/p>\n

Let’s dig a bit deeper, open the compiled program in .NET Reflector<\/a> and disassemble it (if you don’t have .NET Reflector you have to stop reading NOW and get it!! Seriously, this tool is a life-safer and I’ve learned soooo much using it!).<\/p>\n

<\/p>\n

If you focus on the parts I highlighted in red in the above picture you can see that <<\/span>Title<\/span>><\/span> consists out of the XML name and the XML namespace (check out XName..::.Get Method (String, String)<\/a>). Since I didn’t import the namespace in my program an empty namespace got used resulting in the qualified name<\/a> Title<\/font> which doesn’t fit the namespace of the Code Snippet {http:\/\/schemas.microsoft.com\/VisualStudio\/2005\/CodeSnippet}Title<\/font>, hence my program didn’t return any results.<\/p>\n

To solve this problem I added the following line of code to my program <\/p>\n

Imports<\/span> <<\/span>xmlns<\/span>=<\/span>“<\/span>http:\/\/schemas.microsoft.com\/VisualStudio\/2005\/CodeSnippet<\/span>“<\/span>><\/span><\/span><\/p>\n

<\/span><\/span>and – finally – all is good \ud83d\ude42<\/p>\n

<\/p>\n

Hopefully this solved the mystery of the missing results \ud83d\ude09<\/p>\n

Best!<\/p>\n

    Daniel<\/p><\/p>\n","protected":false},"excerpt":{"rendered":"

Hi, I posted a bit of code the other day which I used to get a list of all Code Snippets we ship in Visual Studio. In a nutshell, I used XElement.Load to create a new XML document from a filename from which I then read elements from (There are way to many ‘”from” in […]<\/p>\n","protected":false},"author":260,"featured_media":8818,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[192,195],"tags":[52,94,185],"class_list":["post-2853","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-featured","category-visual-basic","tag-daniel-walzenbach","tag-linqvb9","tag-xml"],"acf":[],"blog_post_summary":"

Hi, I posted a bit of code the other day which I used to get a list of all Code Snippets we ship in Visual Studio. In a nutshell, I used XElement.Load to create a new XML document from a filename from which I then read elements from (There are way to many ‘”from” in […]<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/vbteam\/wp-json\/wp\/v2\/posts\/2853","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/devblogs.microsoft.com\/vbteam\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/devblogs.microsoft.com\/vbteam\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/vbteam\/wp-json\/wp\/v2\/users\/260"}],"replies":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/vbteam\/wp-json\/wp\/v2\/comments?post=2853"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/vbteam\/wp-json\/wp\/v2\/posts\/2853\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/vbteam\/wp-json\/wp\/v2\/media\/8818"}],"wp:attachment":[{"href":"https:\/\/devblogs.microsoft.com\/vbteam\/wp-json\/wp\/v2\/media?parent=2853"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/vbteam\/wp-json\/wp\/v2\/categories?post=2853"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/vbteam\/wp-json\/wp\/v2\/tags?post=2853"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}