【C＃ - 方法封装】数据转换

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一、DataTable & List 相互转换

1.DataTable 转换为 List

using System.Data;
using System.Reflection;

/// <summary>
/// DataTable转换为List<T>对象
/// </summary>
/// <param name="dataTable">DataTable 对象</param>
/// <returns>List<T>集合</returns>
public static List<T> DataTableToList<T>(DataTable dataTable) where T : class, new()
{
    
    // 定义集合
    List<T> ts = new List<T>();
    //定义一个临时变量
    string tempName = string.Empty;
    //遍历DataTable中所有的数据行
    foreach (DataRow dr in dataTable.Rows)
    {
    
        T t = new T();
        // 获得此模型的公共属性
        PropertyInfo[] propertys = t.GetType().GetProperties();
        //遍历该对象的所有属性
        foreach (System.Reflection.PropertyInfo pi in propertys)
        {
    
            tempName = pi.Name;//将属性名称赋值给临时变量
            //检查DataTable是否包含此列（列名==对象的属性名）
            if (dataTable.Columns.Contains(tempName))
            {
    
                //取值
                object value = dr[tempName];
                //如果非空，则赋给对象的属性
                if (value != DBNull.Value)
                {
    
                    pi.SetValue(t, value, null);
                }
            }
        }
        //对象添加到泛型集合中
        ts.Add(t);
    }
    return ts;
}

2.List 转换为 DataTable

需要引用Newtonsoft.Json包

using Newtonsoft.Json;
using System.Data;

/// <summary>
/// List<T>转换为DataTable
/// </summary>
/// <param name="list">请求的list</param>
/// <returns></returns>
public static DataTable ListToDataTable<T>(List<T> list)
{
    
    //创建一个空表
    DataTable dt = new DataTable("tableName");

    //创建传入对象名称的列
    foreach (var item in list.FirstOrDefault().GetType().GetProperties())
    {
    
        dt.Columns.Add(item.Name);
    }
    //循环存储
    foreach (var item in list)
    {
    
        //新加行
        DataRow value = dt.NewRow();
        //根据DataTable中的值，进行对应的赋值
        foreach (DataColumn dtColumn in dt.Columns)
        {
    
            int i = dt.Columns.IndexOf(dtColumn);
            //基元元素，直接复制，对象类型等，进行序列化
            if (value.GetType().IsPrimitive)
            {
    
                value[i] = item.GetType().GetProperty(dtColumn.ColumnName).GetValue(item);
            }
            else
            {
    
                value[i] = JsonConvert.SerializeObject(item.GetType().GetProperty(dtColumn.ColumnName).GetValue(item));
            }
        }
        dt.Rows.Add(value);
    }
    
    return dt;
}

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二、DataTable & Json 相互转换

1.DataTable 转换为 Json字符串

需要引用Newtonsoft.Json包

using Newtonsoft.Json;
using System.Collections;
using System.Data;

/// <summary>
/// DataTable转换为Json字符串
/// </summary>
/// <param name="dataTable">DataTable 对象</param>
/// <returns>JSON字符串</returns>
public static string DataTableToJson(DataTable dataTable)
{
    
    //定义ArrayList
    ArrayList arrayList = new ArrayList();
    //遍历DataTable中所有的数据行
    foreach (DataRow dr in dataTable.Rows)
    {
    
        //定义字典【列名，值】
        Dictionary<string, object> columnsDic = new Dictionary<string, object>();
        //遍历DataTable中所有的数据列
        foreach (DataColumn dc in dataTable.Columns)
        {
    
            //字典添加列名，值
            columnsDic.Add(dc.ColumnName, dr[dc.ColumnName]);
        }
        //arrayList添加字典
        arrayList.Add(columnsDic);
    }
    //序列化
    return JsonConvert.SerializeObject(arrayList);
}

2.Json 转换为 DataTable

using System.Data;
using System.Text.RegularExpressions;

/// <summary>
/// Json转换为DataTable
/// </summary>
/// <param name="strJson">得到的json</param>
/// <returns></returns>
public static 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;
}

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