必须在非泛型静态类中定义扩展方法 - 从文档中提取XML

Question

我目前正在编写一个上传系统，它从文档中获取XML并将其显示在网页上。

我面临的问题是，每当我添加网站的XML提取部分时，编译器将返回标题中提到的错误。

我的代码目前看起来像这样。

导致问题的部分是publicstatic Xnamespace w以及以下所有相关的XML代码。 干杯。

<script runat="server">
    //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 < 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<XDocument>();
            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 =>
                        new XElement("Table",
                            new XAttribute("Name", (string)tableContentControl
                                .Element(W.sdtPr).Element(W.tag).Attribute(
                                    W.val)),
                            tableContentControl
                                    .Descendants(W.sdt)
                                    .Select(fieldContentControl =>
                                            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 






</script>

<!-- The following section will include all the html and forms etc !-->

<!-- on implementation, create different divs for each section, and style appropriately.  !-->
<div>


<!--Testing View state form!-->
ViewState Data: <b><asp:Label ID="lblString" runat="server"/></b>
<asp:Button ID="btnClick" runat="server" Text="Get ViewState Data" OnClick="btnClick_Click"/>
<asp:Button ID="Closeform" runat="server" Text ="Hide PageState" OnClick="Close" />


<br /><br /><br /><br /><br />

<!-- User upload control !-->
<asp:FileUpload id="FileUploadControl" runat="server" />
<asp:Button runat="server" id="UploadButton" text="Upload" onclick="UploadButton_Click" />
<asp:TextBox Text="" runat="server" ID="displayFilepath" />
<br /><br />
<asp:Label runat="server" id="StatusLabel" text="Upload status: " />

 <br /> <br /> <br /> <br />



<!-- Viewdata2, the document and data from DB will be displayed !-->

<!-- Document data !-->
<div id="box1" class="box">

    <div class="box-top">
        Data Sources inside document
    </div>
    <div class="box-middle">
        <asp:Label runat="server" id="labelContentControls" text="label of content in document" />
        <p> Test </p>
        <p> Test </p>
    </div>
    <div class="box-bottom">
    </div>
</div>    

<!--Data from DB !-->
<div id="box2" class="box">

    <div class="box-top">
        Data sources existing on the server
    </div>
    <div class="box-middle">
        <asp:Label runat="server" id="labelDatabasefields" text="label of content in database" />
        <p> Test </p>
        <p> Test </p>
    </div>
    <div class="box-bottom">
    </div>
</div>


<input type="button" value="Create Template" id="view" class="form_button"/>



</div>

Answer 1

是的，这是问题所在：

public static XDocument GetXDocument(this OpenXmlPart part)

这不是在顶级静态非泛型类中声明的，扩展方法必须是。

我强烈建议你停止混合代码和HTML - 将代码放在代码隐藏和其他类中。 GetXDocument方法需要在一个单独的类中，因为它需要根据编译错误在静态类中。

编辑：一个令人讨厌的替代方案是让它不是一个扩展方法：

public static XDocument GetXDocument(OpenXmlPart part)

然后你的电话看起来像这样：

document.MainDocumentPart
        .GetXDocument()

将需要：

GetXDocument(document.MainDocumentPart)

Answer 2

C＃允许创建扩展方法 。 在定义中使用此关键字的方法，例如：

  public static XDocument GetXDocument(this OpenXmlPart part)

但是这种扩展方法只能放在静态类中。 您不能将它们放在非静态类中。 因此，您需要将其移动到新的静态类并使用它，或者只是删除此关键字并使用通常的方法

Answer 3

您已在错误的位置定义了扩展方法。 在一些静态类中定义扩展方法GetXDocument ，而不是在Page类中定义。

public static class YourStaticMethods
{
       public static XDocument GetXDocument(this OpenXmlPart part)
        {
            XDocument xdoc = part.Annotation<XDocument>();
            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;
        }
}

将方法添加到字符串类的扩展方法示例。

namespace ExtensionMethods
{
    public static class MyExtensions
    {
        public static int WordCount(this String str)
        {
            return str.Split(new char[] { ' ', '.', '?' }, 
                             StringSplitOptions.RemoveEmptyEntries).Length;
        }
    }   
}

您可以在此处了解扩展方法。

Answer 4

这个方法：

    public static XDocument GetXDocument(this OpenXmlPart part)
    {
       ....
    }

必须在您的应用程序的public static类中声明。 比如，例如：

public static class Extensions {


        public static XDocument GetXDocument(this OpenXmlPart part)
        {
          ....
        }
}

通过编写this OpenXmlPart您可以指定ExtensionMethod 。 这是另一种“花哨”的方式，用于在.NET应用程序中实现Decorator模式。