在.Net 2.0中写入并从XML文件中读取二进制数据

I've ready many posts (such as this one) on SO now which explain how to write binary data to an XML using the XMLWriter.WriteBase64 method. However, I've yet to see one which explains how to then read the base64'd data. Is there another built in method? I'm also having a hard time finding solid documentation on the subject.

我已经在SO上准备了许多帖子(例如这个帖子),它解释了如何使用XMLWriter.WriteBase64方法将二进制数据写入XML。但是,我还没有看到一个解释如何读取base64'd数据的内容。还有其他内置方法吗?我也很难找到关于这个主题的可靠文档。

Here is the XML file that I'm using:

这是我正在使用的XML文件:

<?xml version="1.0"?>
<pstartdata>
  <pdata>some data here</pdata>
  emRyWVZMdFlRR0FFQUNoYUwzK2dRUGlBS1ZDTXdIREF ..... and much, much more.
</pstartdata>

The C# code which creates that file (.Net 4.0):

创建该文件的C#代码(.Net 4.0):

FileStream fs = new FileStream(Path.GetTempPath() + "file.xml", FileMode.Create);

            System.Xml.XmlTextWriter w = new System.Xml.XmlTextWriter(fs, null);
            w.Formatting = System.Xml.Formatting.None;

            w.WriteStartDocument();
            w.WriteStartElement("pstartdata");
            #region Main Data
            w.WriteElementString("pdata", "some data here");

            // Write the binary data
            w.WriteBase64(fileData[1], 0, fileData[1].Length);
            #endregion (End) Main Data (End)

            w.WriteEndDocument();
            w.Flush();
            fs.Close();

Now, for the real challenge... Alright, so as you all can see the above was written in .Net 4.0. Unfortunately, the XML file needs to be read by an application using .Net 2.0. Reading in the binary (base 64) data has proven to be quite the challenge.

现在,对于真正的挑战......好吧,所以你们都可以看到上面写的是.Net 4.0。不幸的是,XML文件需要由使用.Net 2.0的应用程序读取。读取二进制(base 64)数据已被证明是一项挑战。

Code to read in XML data (.Net 2.0):

System.Xml.XmlDocument xDoc = new System.Xml.XmlDocument();

            xDoc.LoadXml(xml_data);

            foreach (System.Xml.XmlNode node in xDoc.SelectNodes("pstartdata"))
            {
                foreach (System.Xml.XmlNode child in node.ChildNodes)
                {
                    MessageBox.Show(child.InnerXml);
                }
            }

What would I need to add in order to read in the base 64'd data (shown above)?

我需要添加什么才能读入基础64位数据(如上所示)?

2 个解决方案

#1

You seem to write some bad XML - use the following to write the data:

您似乎写了一些不好的XML - 使用以下内容来编写数据:

        w.WriteStartDocument();
        w.WriteStartElement("pstartdata");
        #region Main Data
        w.WriteElementString("pdata", "some data here");

        // Write the binary data
        w.WriteStartElement("bindata");
        w.WriteBase64(fileData[1], 0, fileData[1].Length);
        w.WriteEndElement();
        #endregion (End) Main Data (End)

        w.WriteEndDocument();
        w.Flush();
        fs.Close();

For reading you will have to use XmlReader.ReadContentAsBase64.

要阅读,您必须使用XmlReader.ReadContentAsBase64。

As you have asked for other methods to write and read binary data - there are XmlTextWriter.WriteBinHex and XmlReader.ReadContentAsBinHex. BEWARE that these produce longer data than their Base64 pendants...

正如您要求其他方法来编写和读取二进制数据一样 - 有XmlTextWriter.WriteBinHex和XmlReader.ReadContentAsBinHex。请注意,这些数据产生的数据比Base64吊坠更长......

#2

To read data from XML, you can use an XmlReader, specifically the ReadContentAsBase64 method.

要从XML读取数据,可以使用XmlReader,特别是ReadContentAsBase64方法。

Another alternative is to use Convert.FromBase64String:

另一种方法是使用Convert.FromBase64String:

byte[] binaryData;
try 
{
  binaryData = System.Convert.FromBase64String(base64String);
}

Note: you should look at the code your are using for writing - it appears that you are writing the binary data into the pstartdata element (as well as a pdata element beforehand). Doesn't look quite right - see the answer from @Yahia.

注意:您应该查看用于编写的代码 - 看起来您正在将二进制数据写入pstartdata元素(以及事先的pdata元素)。看起来不太对劲 - 请看@Yahia的答案。

#1