如何从xml文件中检索，更新，追加和删除记录 [英] how to retrieve, Update, append and delete record from xml file

问题描述

Hello house;



我正在开发一个项目，要求我使用xml文件来保存用户的记录，我一直在保存记录，但仍然有问题追加新记录，删除记录，更新和检索记录，我在网上做了一些搜索，但没有成功。以下是我的代码：

Hello house;

I am working on a project that requires me to use xml file to save user's record, i have been to save the record, but still having issues appending a new record, deleting a record, updating and retrieving records, i have done a few searches online, but no success. Below is my code:

var writer = new XmlTextWriter( "XMLFile1.xml", System.Text.Encoding.UTF8 );
            writer.WriteStartDocument( true );
            writer.Formatting = Formatting.Indented;
            writer.Indentation = 2;
            writer.WriteStartElement( "Table" );
            createNode( "5", "Product 5", "5000", writer );
            createNode( "6", "Product 6", "5000", writer );
            createNode( "7", "Product 7", "5000", writer );
            createNode( "9", "Product 8", "5000", writer );
            writer.WriteEndElement( );
            writer.WriteEndDocument( );
            writer.Close( );

private void createNode(string pID, string pName, string pPrice, XmlTextWriter writer)
        {
            writer.WriteStartElement( "Product" );
            writer.WriteStartElement( "Product_id" );
            writer.WriteString( pID );
            writer.WriteEndElement( );
            writer.WriteStartElement( "Product_name" );
            writer.WriteString( pName );
            writer.WriteEndElement( );
            writer.WriteStartElement( "Product_price" );
            writer.WriteString( pPrice );
            writer.WriteEndElement( );
            writer.WriteEndElement( );
        }

以上代码成功写入xml文件，我希望能够检索，追加新记录，更新并删除记录。任何帮助将不胜感激。在此先感谢。

The above codes writes successfully to xml file, i want o be able to retrieve, append new record, update and delete record. Any assistance will be greatly appreciated. Thanks in advance.

推荐答案

看看这个：

1. 插入-更新删除功能于XML的文件使用-C-夏普/ [< a href =http://www.c-sharpcorner.com/UploadFile/b8e86c/insert-update-delete-in-xml-file-using-C-Sharp/target =_ blanktitle =New Window > ^ ]

2. 如何附加到大型XML文件 [ ^ ]

Check this out:
1. insert-update-delete-in-xml-file-using-C-Sharp/[^]
2. How to Append to a Large XML File[^]

如果您使用 LINQ XDocument 和 XElement 我认为这对你来说更容易。

If you use LINQ with XDocument and XElement I think it is easier for you.

XElement xeTable = new XElement("Table");

XElement xeProducts = new XElement("Product");
createNode("5", "Product 5", "5000", xeProducts);
createNode("6", "Product 6", "5000", xeProducts);
createNode("7", "Product 7", "5000", xeProducts);
createNode("8", "Product 8", "5000", xeProducts);

xeTable.Add(xeProducts);

XDocument xdoc = new XDocument();
xdoc.Declaration = new XDeclaration("1.0", "utf8", "yes");
xdoc.Add(xeTable);
xdoc.Save(@"XMLFile1.xml");

private void createNode(string pID, string pName, string pPrice, XElement xeProducts)
{
    XElement xeProduct = new XElement("Product");
    xeProduct.Add(new XElement("Product_id", pID));
    xeProduct.Add(new XElement("Product_name", pName));
    xeProduct.Add(new XElement("Product_price", pPrice));
    xeProducts.Add(xeProduct);
}

生成的XML

Resulting XML

<Products>
  <Product>
    <Product_id>5</Product_id>
    <Product_name>Product 5</Product_name>
    <Product_price>5000</Product_price>
  </Product>
  <Product>
    <Product_id>6</Product_id>
    <Product_name>Product 6</Product_name>
    <Product_price>5000</Product_price>
  </Product>
  <Product>
    <Product_id>7</Product_id>
    <Product_name>Product 7</Product_name>
    <Product_price>5000</Product_price>
  </Product>
  <Product>
    <Product_id>8</Product_id>
    <Product_name>Product 8</Product_name>
    <Product_price>5000</Product_price>
  </Product>
</Products>

< br $> b $ b



如何读取文件的示例：

Example of how to read the file:

XDocument xdoc2 = XDocument.Load(@"XMLFile1.xml");
XElement xeProducts2 = xdoc2.Root.Element("Products");

XElement xeProduct7 = xeProducts.Elements("Product").
Where(x => x.Element("Product_id").Value == "7").FirstOrDefault();

查询结果：

Result of the query:

<Product>
  <Product_id>7</Product_id> 
  <Product_name>Product 7</Product_name> 
  <Product_price>5000</Product_price> 
</Product>

访问会员

Access the members

string productName = xeProduct7.Element("Product_name").Value;

追加

Append

XDocument xdoc = XDocument.Load(@"XMLFile1.xml");
XElement xeProducts = xdoc.Root.Element("Products");
createNode("10", "Product 10", "10000", xeProducts);
xdoc.Save(@"XMLFile1.xml");

删除

Delete

XDocument xdoc = XDocument.Load(@"XMLFile1.xml");
XElement xeProducts = xdoc.Root.Element("Products");
XElement xeProduct7 = xeProducts.Elements("Product").
   Where(x => x.Element("Product_id").Value == "7").FirstOrDefault();
xeProduct7.Remove();
xdoc.Save(@"XMLFile1.xml");

从这里你需要使用你自己的大脑la。

From here on you need to use your own brain la.

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