DataTable ，XML和JSON相互转化

网上搜集的，保留下来了，有需要的拿去！
private string DataTable2Xml(DataTable dt)
{
StringBuilder xmlBuilder = new StringBuilder();
xmlBuilder.Append("<?xml version=\"1.0\" encoding=\"utf-8\" ?>");
xmlBuilder.Append("<documentElement>");
xmlBuilder.Append("<" + dt.TableName + ">");

for (int i = 0; i < dt.Rows.Count; i++)
{
//xmlBuilder.Append("<" + dt.TableName + ">");
for (int j = 0; j < dt.Columns.Count; j++)
{
xmlBuilder.Append("<" + dt.Columns[j].ColumnName + ">");
xmlBuilder.Append(dt.Rows[i][j].ToString());
xmlBuilder.Append("</" + dt.Columns[j].ColumnName + ">");
}
//xmlBuilder.Append("</" + dt.TableName + ">");
}
xmlBuilder.Append("</" + dt.TableName + ">");

xmlBuilder.Append("</documentElement>");
return xmlBuilder.ToString();
}

private string DataTable2Json(DataTable dt,bool withTableName)
{
StringBuilder jsonBuilder = new StringBuilder();
if (withTableName)
{
jsonBuilder.Append("{\"");
jsonBuilder.Append(dt.TableName);
jsonBuilder.Append("\":");
}
jsonBuilder.Append("[");
for (int i = 0; i < dt.Rows.Count; i++)
{
jsonBuilder.Append("{");
for (int j = 0; j < dt.Columns.Count; j++)
{
jsonBuilder.Append("\"");
jsonBuilder.Append(dt.Columns[j].ColumnName);
jsonBuilder.Append("\":\"");
jsonBuilder.Append(dt.Rows[i][j].ToString());
jsonBuilder.Append("\",");
}
jsonBuilder.Remove(jsonBuilder.Length - 1, 1);
jsonBuilder.Append("},");
}
jsonBuilder.Remove(jsonBuilder.Length - 1, 1);
jsonBuilder.Append("]");
if(withTableName)jsonBuilder.Append("}");
return jsonBuilder.ToString();
}

#region DataTable 转换为Json 字符串
/// <summary>
/// DataTable 对象 转换为Json 字符串
/// </summary>
/// <param name="dt"></param>
/// <returns></returns>
public static string ToJson(this DataTable dt)
{
JavaScriptSerializer javaScriptSerializer = new JavaScriptSerializer();
javaScriptSerializer.MaxJsonLength = Int32.MaxValue; //取得最大数值
ArrayList arrayList = new ArrayList();
foreach (DataRow dataRow in dt.Rows)
{
Dictionary<string, object> dictionary = new Dictionary<string, object>();  //实例化一个参数集合
foreach (DataColumn dataColumn in dt.Columns)
{
dictionary.Add(dataColumn.ColumnName, dataRow[dataColumn.ColumnName].ToStr());
}
arrayList.Add(dictionary); //ArrayList集合中添加键值
}

return javaScriptSerializer.Serialize(arrayList);  //返回一个json字符串
}
#endregion

#region Json 字符串 转换为 DataTable数据集合
/// <summary>
/// Json 字符串 转换为 DataTable数据集合
/// </summary>
/// <param name="json"></param>
/// <returns></returns>
public static DataTable ToDataTable(this string json)
{
DataTable dataTable = new DataTable();  //实例化
DataTable result;
try
{
JavaScriptSerializer javaScriptSerializer = new JavaScriptSerializer();
javaScriptSerializer.MaxJsonLength = Int32.MaxValue; //取得最大数值
ArrayList arrayList = javaScriptSerializer.Deserialize<ArrayList>(json);
if (arrayList.Count > 0)
{
foreach (Dictionary<string, object> dictionary in arrayList)
{
if (dictionary.Keys.Count<string>() == 0)
{
result = dataTable;
return result;
}
if (dataTable.Columns.Count == 0)
{
foreach (string current in dictionary.Keys)
{
dataTable.Columns.Add(current, dictionary[current].GetType());
}
}
DataRow dataRow = dataTable.NewRow();
foreach (string current in dictionary.Keys)
{
dataRow[current] = dictionary[current];
}

dataTable.Rows.Add(dataRow); //循环添加行到DataTable中
}
}
}
catch
{
}
result = dataTable;
return result;
}
#endregion

/// <summary>
/// 将json转换为DataTable
/// </summary>
/// <param name="strJson">得到的json</param>
/// <returns></returns>
private DataTable JsonToDataTable(string strJson)
{
//转换json格式
strJson = strJson.Replace(",\"", "*\"").Replace("\":", "\"#").ToString();
//取出表名
var rg = new Regex(@"(?<={)[^:]+(?=:\[)", RegexOptions.IgnoreCase);
string strName = rg.Match(strJson).Value;
DataTable tb = null;
//去除表名
strJson = strJson.Substring(strJson.IndexOf("[") + 1);
strJson = strJson.Substring(0, strJson.IndexOf("]"));

//获取数据
rg = new Regex(@"(?<={)[^}]+(?=})");
MatchCollection mc = rg.Matches(strJson);
for (int i = 0; i < mc.Count; i++)
{
string strRow = mc[i].Value;
string[] strRows = strRow.Split('*');

//创建表
if (tb == null)
{
tb = new DataTable();
tb.TableName = strName;
foreach (string str in strRows)
{
var dc = new DataColumn();
string[] strCell = str.Split('#');

if (strCell[0].Substring(0, 1) == "\"")
{
int a = strCell[0].Length;
dc.ColumnName = strCell[0].Substring(1, a - 2);
}
else
{
dc.ColumnName = strCell[0];
}
tb.Columns.Add(dc);
}
tb.AcceptChanges();
}

//增加内容
DataRow dr = tb.NewRow();
for (int r = 0; r < strRows.Length; r++)
{
dr[r] = strRows[r].Split('#')[1].Trim().Replace("，", ",").Replace("：", ":").Replace("\"", "");
}
tb.Rows.Add(dr);
tb.AcceptChanges();
}

return tb;
}

public static DataTable JsonToDataTable(string strJson)
{
//取出表名
Regex rg = new Regex(@"(?<={)[^:]+(?=:/[)", RegexOptions.IgnoreCase);
string strName = rg.Match(strJson).Value;
DataTable tb = null;
//去除表名
strJson = strJson.Substring(strJson.IndexOf("[") + 1);
strJson = strJson.Substring(0, strJson.IndexOf("]"));

//获取数据
rg = new Regex(@"(?<={)[^}]+(?=})");
MatchCollection mc = rg.Matches(strJson);
for (int i = 0; i < mc.Count; i++)
{
string strRow = mc[i].Value;
string[] strRows = strRow.Split(',');

//创建表
if (tb == null)
{
tb = new DataTable();
tb.TableName = strName;
foreach (string str in strRows)
{
DataColumn dc = new DataColumn();
string[] strCell = str.Split(':');
dc.ColumnName = strCell[0].ToString();
tb.Columns.Add(dc);
}
tb.AcceptChanges();
}

//增加内容
DataRow dr = tb.NewRow();
for (int r = 0; r < strRows.Length; r++)
{
dr[r] = strRows[r].Split(':')[1].Trim().Replace("，", ",").Replace("：", ":").Replace("/"", "");
}
tb.Rows.Add(dr);
tb.AcceptChanges();
}

return tb;
}