title: Extension method must be defined in a non-generic static class - Pulling XML from document
body: <p>I'm currently writing up an upload system that takes XML from the document and will display it on a web page.</p>
  
  <p>The issue I'm facing, is that whenever I'm adding the XML extraction part of the website, the compiler will return the error as mentioned in the title.</p>
  
  <p>My code currently looks like this. </p>
  
  <p>The part that is causing the problem is the publicstatic Xnamespace w and all the following relevant XML code. Cheers.</p>
  
  <pre><code>&lt;script runat="server"&gt;
      //This template is being built to allow the viewstates to be displayed and allow them to be hidden
      //or shown at the same time. The buttons are being added so we can test whether they will
      //be hidden on page use
  
  
      public string _TempFileLocation = ""; //Used to locate Word Document File Path 
  
  
      protected void Page_Load(object sender, EventArgs e)
      {
          if (!IsPostBack)
          {
  
  
              string viewStateDisplay1 = "ViewState1 is now being displayed";
              string viewStateDisplay2 = "ViewState2 is now being displayed";
             // var ViewShow = viewStateDisplay1;
             // var ViewShow2 = viewStateDisplay2; 
  
              if (ViewState["PageState"] == null)
              {
                  ViewState["PageState"] = viewStateDisplay1;
              }
  
                  else
                  {
                      ViewState["PageState"] = viewStateDisplay2;
                      //viewStateDisplay = false;
                  }
          }
  
      }
  
      //button that shows the label string
      protected void btnClick_Click(object sender, EventArgs e)
      {
          lblString.Text = ViewState["PageState"].ToString();
          lblString.Visible = true;
      }
  
      //button that hides the div, changing "lblstring" or adding more should be able to hide 
      //or show whatever methods / objects we want
      private void Close(object sender, EventArgs e)
      {
          lblString.Visible = !lblString.Visible;
          lblString.Visible = false;
      }
  
  
      //This will be the default set for the page. It will start on true for viewstatedisplay
      //this will be done again, but with viewstatedisplay2 for the next method regarding 
      //the two columns and displaying document and DB data. "viewStateDisplay2.Visible = true"
  
      //private void gotoviewStateDisplay1(object sender, EventArgs e)
      // {
      //   ViewState("PageState") = 1;
      //   viewStateDisplay1.Visible = true;
      //   viewStateDisplay2.Visible = false;
      //}
  
      //private void gotoviewStateDisplay2(object sender, EventArgs e)
      // {
      //   ViewState("PageState") = 2;
      //   viewStateDisplay1.Visible = false;
      //   viewStateDisplay2.Visible = true;
      //}
  
  
  
  
      //THE USER UPLOAD CONTROL. users use this to upload the document to the server
      //This has validation so they cannot upload wrong file types / too large files
  
     // public partial class UploadFileControl : System.Web.UI.UserControl
    //  {
  
          //ViewState1 
  
          public void XMLextractor(string _filePath)
          {
  
              //XML extraction code
             displayFilepath.Text = _filePath;
             _TempFileLocation = _filePath;
  
          }
  
          //names the script manager which will be used when the user attempts to upload a form / gives an error if they incorrectly attempt to upload
          protected void UploadButton_Click(object sender, EventArgs e)
          {
              //if file is located
              if (FileUploadControl.HasFile)
              {
                  try
                  {
                      //allow content type of document / docx
                      if (FileUploadControl.PostedFile.ContentType == "application/vnd.openxmlformats-officedocument.wordprocessingml.document")
                      {
                          //if the file is is less than 51mb
                          if (FileUploadControl.PostedFile.ContentLength &lt; 10485760) // 10mb)
                          {
                              //name the filename, find the path of the name
                              string filename = Path.GetFileName(FileUploadControl.FileName);
                              //path of server upload (we just need to save it as a variable to be found on the next page, as it will be made / deleted
                              FileUploadControl.SaveAs(Server.MapPath("~/") + filename);
                              //update the label with file uploaded
                              StatusLabel.Text = "Upload status: File uploaded!";
  
                              XMLextractor(Server.MapPath("~/") + filename);
  
                              //move onto template wizard page
                              //Response.Redirect("http://portal.acoura.com/admin/templatewizard.aspx", false);
  
                            WordprocessingDocument _TempDoc = WordprocessingDocument.Open(Server.MapPath("~/") + filename, true);
  
                           labelContentControls.Text = fileUpload_Displayx(GetContentControls(_TempDoc));
  
                              //will be used to grab the document string
                              //return;
  
                          }
                          else
                              //display the size the file needs to be less than
                              StatusLabel.Text = "Upload status: The file has to be less than 10mb!";
                      }
                      else
                          //tell the user only docx files are accepted
                          StatusLabel.Text = "Upload status: Only DOCX files are accepted!";
                  }
                  catch (Exception ex)
                  {
                      //display the exception message, in which case it would be either size / type / if it's present
                      StatusLabel.Text = "Upload status: The file could not be uploaded. The following error occured: " + ex.Message;
                  }
  
  
              }
  
          }
     // }
  
     //insert or link to XMLfromDocument file here. This will declare the variables
     //and take the required XML sections from the content controls of a document
     //needs to run as the file is uploaded, then return the control content titles
  
         // internal static class W
         //{
  
          //}
  
  
          public static XNamespace w =
              "http://schemas.openxmlformats.org/wordprocessingml/2006/main";
  
          public static XName body = w + "body";
          public static XName sdt = w + "sdt";
          public static XName sdtPr = w + "sdtPr";
          public static XName tag = w + "tag";
          public static XName val = w + "val";
          public static XName sdtContent = w + "sdtContent";
          public static XName tbl = w + "tbl";
          public static XName tr = w + "tr";
          public static XName tc = w + "tc";
          public static XName p = w + "p";
          public static XName r = w + "r";
          public static XName t = w + "t";
          public static XName rPr = w + "rPr";
          public static XName highlight = w + "highlight";
          public static XName pPr = w + "pPr";
          public static XName color = w + "color";
          public static XName sz = w + "sz";
          public static XName szCs = w + "szCs";
  
  
          public static XDocument GetXDocument(this OpenXmlPart part)
          {
              XDocument xdoc = part.Annotation&lt;XDocument&gt;();
              if (xdoc != null)
                  return xdoc;
              using (Stream str = part.GetStream())
              using (StreamReader streamReader = new StreamReader(str))
              using (XmlReader xr = XmlReader.Create(streamReader))
                  xdoc = XDocument.Load(xr);
              part.AddAnnotation(xdoc);
              return xdoc;
          }
  
          public static XElement GetContentControls(WordprocessingDocument document)
          {
  
              XElement contentControls = new XElement("ContentControls",
                  document
                      .MainDocumentPart
                      .GetXDocument()
                      .Root
                      .Element(W.body)
                      .Elements(W.sdt)
                      .Select(tableContentControl =&gt;
                          new XElement("Table",
                              new XAttribute("Name", (string)tableContentControl
                                  .Element(W.sdtPr).Element(W.tag).Attribute(
                                      W.val)),
                              tableContentControl
                                      .Descendants(W.sdt)
                                      .Select(fieldContentControl =&gt;
                                              new XElement("Field",
                                                  new XAttribute("Name",
                                                      (string)fieldContentControl
                                                            .Element(W.sdtPr)
                                                            .Element(W.tag)
                                                            .Attribute(W.val)
                                                      )
                                              )
                                      )
                          )
                      )
              );
              //display the content controls in a web form in this project using this, the control will have to be added to templatewizard
              return contentControls;
  
              //need to mark the source which will be a file in the same directory as this for test purposes.
  
          }
     //display the TemplateWizard boxes and button here, hide viewstate and display viewstate2  
     //display content controls from doc on box1, field names from DB in box2
     //just create a string here that represents the final state of data being taken from XMLfromDocument
  
  
        // public string fileUpload_Displayx (XElement _contentcontrol)
        // {
        //      string str= "";
         //     str= _contentcontrol.Name.ToString();
  
         //    return str;
  
       //  }
  
     //public static displayDatabase(object sender, EventArgs e)
    // {
  
     //}
     //run the validate button on templatewizard, will mark up any problems or give green light
  
  
     //if red, allow users to replace fields in the left column, from ones in the atabase on the right
  
  
     //display upload button when validation is succesful. When Upload button runs, Take to new 
     // / existing page of reports, allow users to download this 
  
  
  
  
  
  
  &lt;/script&gt;
  
  &lt;!-- The following section will include all the html and forms etc !--&gt;
  
  &lt;!-- on implementation, create different divs for each section, and style appropriately.  !--&gt;
  &lt;div&gt;
  
  
  &lt;!--Testing View state form!--&gt;
  ViewState Data: &lt;b&gt;&lt;asp:Label ID="lblString" runat="server"/&gt;&lt;/b&gt;
  &lt;asp:Button ID="btnClick" runat="server" Text="Get ViewState Data" OnClick="btnClick_Click"/&gt;
  &lt;asp:Button ID="Closeform" runat="server" Text ="Hide PageState" OnClick="Close" /&gt;
  
  
  &lt;br /&gt;&lt;br /&gt;&lt;br /&gt;&lt;br /&gt;&lt;br /&gt;
  
  &lt;!-- User upload control !--&gt;
  &lt;asp:FileUpload id="FileUploadControl" runat="server" /&gt;
  &lt;asp:Button runat="server" id="UploadButton" text="Upload" onclick="UploadButton_Click" /&gt;
  &lt;asp:TextBox Text="" runat="server" ID="displayFilepath" /&gt;
  &lt;br /&gt;&lt;br /&gt;
  &lt;asp:Label runat="server" id="StatusLabel" text="Upload status: " /&gt;
  
   &lt;br /&gt; &lt;br /&gt; &lt;br /&gt; &lt;br /&gt;
  
  
  
  &lt;!-- Viewdata2, the document and data from DB will be displayed !--&gt;
  
  &lt;!-- Document data !--&gt;
  &lt;div id="box1" class="box"&gt;
  
      &lt;div class="box-top"&gt;
          Data Sources inside document
      &lt;/div&gt;
      &lt;div class="box-middle"&gt;
          &lt;asp:Label runat="server" id="labelContentControls" text="label of content in document" /&gt;
          &lt;p&gt; Test &lt;/p&gt;
          &lt;p&gt; Test &lt;/p&gt;
      &lt;/div&gt;
      &lt;div class="box-bottom"&gt;
      &lt;/div&gt;
  &lt;/div&gt;    
  
  &lt;!--Data from DB !--&gt;
  &lt;div id="box2" class="box"&gt;
  
      &lt;div class="box-top"&gt;
          Data sources existing on the server
      &lt;/div&gt;
      &lt;div class="box-middle"&gt;
          &lt;asp:Label runat="server" id="labelDatabasefields" text="label of content in database" /&gt;
          &lt;p&gt; Test &lt;/p&gt;
          &lt;p&gt; Test &lt;/p&gt;
      &lt;/div&gt;
      &lt;div class="box-bottom"&gt;
      &lt;/div&gt;
  &lt;/div&gt;
  
  
  &lt;input type="button" value="Create Template" id="view" class="form_button"/&gt;
  
  
  
  &lt;/div&gt;
  </code></pre>