我有一个问题。我正在使用OpenXml将图像以及一些文本放在图像内容控件上。现在我很担心，它会从数据库中提取信息（所有信息似乎都很好）。现在，将图像和内容放在内容控件上是我遇到的主要问题。
我的代码看起来像是一种Web服务。
using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data.SqlClient;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Web;
using System.Web.Services;
using DocumentFormat.OpenXml.Drawing;
using DocumentFormat.OpenXml.Packaging;
using DocumentFormat.OpenXml.Wordprocessing;
using Text = DocumentFormat.OpenXml.Wordprocessing.Text;
namespace eMemoSignatureService
{
/// <summary>
/// Summary description for signaturewebservice
/// </summary>
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[System.ComponentModel.ToolboxItem(false)]
// To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line.
// [System.Web.Script.Services.ScriptService]
public class signaturewebservice : System.Web.Services.WebService
{
string fullname;
string designation;
[WebMethod]
public string HelloWorld()
{
return "Hello World";
}
[WebMethod]
public bool PlaceSignatureonMsWord(string WEMAstaffID)
{
string constring = ConfigurationManager.ConnectionStrings["dbconnection"].ConnectionString;
using (SqlConnection con = new SqlConnection(constring))
{
con.Open();
string sqlq = "select * from [e-SignatureDB].[dbo].[signature_table] where staffID = @staffID";
using (SqlCommand cmd = new SqlCommand(sqlq, con))
{
cmd.Parameters.AddWithValue("@staffID", WEMAstaffID);
SqlDataReader rd = cmd.ExecuteReader();
if (rd.Read())
{
fullname = (rd["fullname"].ToString());
designation = (rd["designation"].ToString());
byte[] bytes = Convert.FromBase64String(rd["approval_signature"].ToString());
Image img;
using (MemoryStream ms = new MemoryStream(bytes))
{
img = Image.FromStream(ms);
string folderPath = Server.MapPath("~/Signature_image/");
string fileName = fullname + ".jpg";
string imagePath = folderPath + fileName;
img.Save(imagePath, System.Drawing.Imaging.ImageFormat.Jpeg);
using (WordprocessingDocument document = WordprocessingDocument.Open(@"C:\Users\emi\Desktop\e-Memo.docx", true))
{
MainDocumentPart mainPart = document.MainDocumentPart;
DocumentFormat.OpenXml.Wordprocessing.Text text = null;
DocumentFormat.OpenXml.Wordprocessing.Text text2 = null;
SdtContentBlock designationBlk = null;
SdtContentBlock fullnameblk = null;
List<SdtBlock> sdtList = mainPart.Document.Descendants<SdtBlock>().ToList();
foreach (SdtBlock sdt in sdtList)
{
Console.WriteLine(sdt.SdtProperties.GetFirstChild<Tag>().Val.Value);
}
if (designation == "Manager")
{
// SdtElement s1 = mainPart.Document.Body.Descendants<SdtElement>().Where(r => r.SdtProperties.GetFirstChild<Tag>().Val == "ManName1").Single();
// SdtElement s2 = mainPart.Document.Body.Descendants<SdtElement>().Where(r => r.SdtProperties.GetFirstChild<Tag>().Val == "ManDesg1").Single();
SdtBlock s1 = mainPart.Document.Body.Descendants<SdtBlock>().Where(r => r.SdtProperties.GetFirstChild<Tag>().Val == "ManName1").Single();
SdtBlock s2 = mainPart.Document.Body.Descendants<SdtBlock>().Where(r => r.SdtProperties.GetFirstChild<Tag>().Val == "ManDesg1").Single();
SdtElement s3 = mainPart.Document.Body.Descendants<SdtElement>().FirstOrDefault(r =>
{
SdtElement p = r.Elements<SdtElement>().FirstOrDefault();
if (p != null)
{
Console.WriteLine("P is not null");
// Is it a picture content control?
SdtContentPicture pict =
p.Elements<SdtContentPicture>().FirstOrDefault();
if (pict != null) Console.WriteLine("Pict is not null");
// Get the alias.
SdtAlias a = p.Elements<SdtAlias>().FirstOrDefault();
if (pict != null && a.Val == "Approval1")
return true;
}
return false;
});
if (s1 != null)
{
fullnameblk = s1.Descendants<SdtContentBlock>().FirstOrDefault();
text = fullnameblk.Descendants<Text>().FirstOrDefault();
text.Text = fullname;
Console.WriteLine(text.Text);
}
if (s2 != null)
{
designationBlk = s2.Descendants<SdtContentBlock>().FirstOrDefault();
text2 = designationBlk.Descendants<Text>().FirstOrDefault();
text2.Text = designation;
Console.WriteLine(text2.Text);
}
string embed = null;
if (s3 != null)
{
Drawing dr = s3.Descendants<Drawing>().FirstOrDefault();
if (dr != null)
{
Blip blip = dr.Descendants<Blip>().FirstOrDefault();
if (blip != null)
embed = blip.Embed;
}
}
if (embed != null)
{
IdPartPair idpp = document.MainDocumentPart.Parts
.Where(pa => pa.RelationshipId == embed).FirstOrDefault();
if (idpp != null)
{
ImagePart ip = (ImagePart)idpp.OpenXmlPart;
using (FileStream fileStream =
File.Open(imagePath, FileMode.Open))
ip.FeedData(fileStream);
}
mainPart.Document.Save();
document.Close();
}
}
}
}
}
}
}
return true;
}
}
}
现在我担心它会在此区域显示错误
if (s1 != null)
{
fullnameblk = s1.Descendants<SdtContentBlock>().FirstOrDefault();
text = fullnameblk.Descendants<Text>().FirstOrDefault();
text.Text = fullname;
Console.WriteLine(text.Text);
}
当我已经从SQL服务器获得数据时。我似乎缺少什么？
答案 0 :(得分：0)
该区域存在一些导致您“担忧”的问题（请参见代码注释）：
// Since you use the Single() method in setting s1, s1 can't be null.
// Otherwise, you would have had an exception already before reaching
// the following if statement.
if (s1 != null)
{
// You could simply say s1.SdtContentBlock.
fullnameblk = s1.Descendants<SdtContentBlock>().FirstOrDefault();
// fullnameblk can theoretically be null and you don't check for that.
// However, unless you have an edge case, this should not be an issue.
text = fullnameblk.Descendants<Text>().FirstOrDefault();
// text can be null (e.g., in an empty paragraph) and you don't check for that.
// This can happen in practice and is not even an edge case.
text.Text = fullname;
Console.WriteLine(text.Text);
}
因此，如果您在System.NullReferenceException上获得text.Text，这是因为您的SdtContentBlock（w:sdtContent）没有任何Text（{{1} }）后代。如果w:t不包含任何SdtContentBlock（Paragraph）或仅包含一个空的w:p，则会发生这种情况。