替换标题占位符，现在不工作

Question

我想在文档的标题中替换占位符'plcDate'。标题从我的文档模板中的第二页开始。

我正在使用下面的代码。但'headDate'始终为空。

不知道我是否需要更改代码或文档模板。

using (WordprocessingDocument theDoc = WordprocessingDocument.Open(NewPath, true)) 
{ 
    MainDocumentPart mainPart = theDoc.MainDocumentPart; 
    foreach (HeaderPart hpart in mainPart.HeaderParts) 
    { 
     SdtElement headDate = hpart.Header.Descendants<SdtElement>().Where(r => r.SdtProperties.GetFirstChild<Tag>().Val == "plcDate").SingleOrDefault(); 
     if (headDate != null) 
     { 
      headDate.Append(new DocumentFormat.OpenXml.Wordprocessing.Paragraph(new Run(new Text(dateValue)))); 
     } 
    } 
    mainPart.Document.Save(); 
} 

Answer 1

使用下面的代码工作后：

using (WordprocessingDocument theDoc = WordprocessingDocument.Open(NewPath, true)) 
       { 
        MainDocumentPart mainPart = theDoc.MainDocumentPart; 
        string content = null; 

        using (StreamReader reader = new StreamReader(theDoc.MainDocumentPart.HeaderParts.First().GetStream())) 
        { 
         content = reader.ReadToEnd(); 
        } 
        Regex exheadDate = new Regex("plcDate"); 
        content = exheadDate.Replace(content, "27/07/1992"); 
        using (StreamWriter writer = new StreamWriter(theDoc.MainDocumentPart.HeaderParts.First().GetStream(FileMode.Create))) 
        { 
         writer.Write(content); 
        } 
        mainPart.Document.Save(); 
       }