项目开发 · 2017年9月10日 0

[C#]DataTable与XML互相转换

using System.Xml;
//使用XmlTextWriter类。
XmlTextWriter writer = new XmlTextWriter(address, Encoding.GetEncoding("GBK"));
//设置缩进值
writer.Formatting = Formatting.Indented;
//XML文档创建开始
writer.WriteStartDocument();
//填写注释:
writer.WriteComment("这是一个注释");
//开始标签:
writer.WriteStartElement("data");
//标签中的参数:
writer.WriteAttributeString("param1","value1");
//结束上一个标签:
writer.WriteEndElement();
//结束文档
writer.WriteEndDocument();
//关闭文件
writer.Close();

一开始还犯了个错误,XML格式的文件只支持这种格式

<a>
<b>
内容1
</b>
<c>
内容2
</c>
</a>

不支持这种方式

<a>
内容1
</a>
<b>
内容2
</b>

所以一般在最开始和结尾用ROOT标签包围起来保证不会出错

DataSet与XML相互转换

public static bool WriteToXml(DataSet ds, string address)
{
    try
    {
        //如果文件DataTable.xml存在则直接删除
        if (File.Exists(address))
        {
            File.Delete(address);
        }
        XmlTextWriter writer =
        new XmlTextWriter(address, Encoding.GetEncoding("GBK"));
        writer.Formatting = Formatting.Indented;
        writer.WriteStartDocument();//XML文档创建开始
        writer.WriteStartElement("ROOT"); //防止xml出错,定义一个开始的根节点

        foreach (DataTable dt in ds.Tables)
        {
            writer.WriteComment("DataTable: " + dt.TableName);//注释
            writer.WriteStartElement("data"); //开始一个datatable
            writer.WriteAttributeString("TableName", dt.TableName);//data标签中添加表名
            writer.WriteAttributeString("CountOfRows", dt.Rows.Count.ToString());//data标签中添加行数
            writer.WriteAttributeString("CountOfColumns", dt.Columns.Count.ToString());//data标签中添加列数
            writer.WriteStartElement("ClomunName", ""); //ColumnName开始
            for (int i = 0; i < dt.Columns.Count; i++)
            {
                writer.WriteAttributeString("Column" + i.ToString(), dt.Columns[i].ColumnName);
            }
            writer.WriteEndElement(); //ColumnName结束
            //按行各行
            for (int j = 0; j < dt.Rows.Count; j++)
            {
                writer.WriteStartElement("Row" + j.ToString(), "");
                //打印各列
                for (int k = 0; k < dt.Columns.Count; k++)
                {
                    writer.WriteAttributeString("Column" + k.ToString(), dt.Rows[j][k].ToString());
                }
                writer.WriteEndElement();
            }
            writer.WriteEndElement(); //结束一个datatable
        }

        writer.WriteEndElement();//结束根节点
        writer.WriteEndDocument();//结束文档
        writer.Close();
        //XML文档创建结束
    }
    catch (Exception ex)
    {
        LogUtils.writeErrorLog("【WriteToXml错误】:"+ex.ToString());
        return false;
    }
    return true;
}
public static DataSet ReadFromXml(string address)
{
    DataSet ds = new DataSet();
    string err_name = "";
    try
    {
        if (!File.Exists(address))
        {
            err_name = "文件不存在!";
            throw new Exception("文件不存在!");
        }

        XmlDocument xmlDoc = new XmlDocument();
        xmlDoc.Load(address);

        XmlNode Root = xmlDoc.SelectSingleNode("ROOT");
        XmlNodeList x = Root.ChildNodes;
        foreach (XmlNode root in x)
        {
            if (root.Attributes == null)
                continue;
            DataTable dt = new DataTable();

            //读取表名
            string tb_name = ((XmlElement)root).GetAttribute("TableName");
            //string tb_name = ((XmlElement)root).GetAttribute("TableName");
            dt.TableName = tb_name;
            //读取行数
            int CountOfRows = 0;
            if (!int.TryParse(((XmlElement)root).GetAttribute("CountOfRows").ToString(), out CountOfRows))
            {
                err_name = "["+tb_name+"]"+"行数转换失败";
                throw new Exception("行数转换失败");
            }
            //读取列数
            int CountOfColumns = 0;
            if (!int.TryParse(((XmlElement)root).GetAttribute("CountOfColumns").ToString(), out CountOfColumns))
            {
                err_name = "[" + tb_name + "]" + "列数转换失败";
                throw new Exception("列数转换失败");
            }

            //从第一行中读取记录的列名
            foreach (XmlAttribute xa in root.ChildNodes[0].Attributes)
            {
                dt.Columns.Add(xa.Value);
                //Console.WriteLine("建立列: {0}", xa.Value);
            }

            //从后面的行中读取行信息
            for (int i = 1; i < root.ChildNodes.Count; i++)
            {
                string[] array = new string[root.ChildNodes[0].Attributes.Count];
                for (int j = 0; j < array.Length; j++)
                {
                    array[j] = root.ChildNodes[i].Attributes[j].Value.ToString();
                }
                dt.Rows.Add(array);
                //Console.WriteLine("行插入成功");
            }
            //添加到ds中
            ds.Tables.Add(dt);
        }
    }
    catch (Exception ex)
    {
        LogUtils.writeErrorLog("【ReadFromXml错误】:" + ex.ToString());
        err_name = ex.Message;
        ds = new DataSet();
        ds.DataSetName = err_name;
        return ds;
    }
    return ds;
}