C# DataTable 转JSON、List 转DataTable、DataTable转List

1.DataTable To Json:

public string DataTableToJsonWithStringBuilder(DataTable table)
        {
            var jsonString = new StringBuilder();
            if (table.Rows.Count > 0)
            {
                jsonString.Append("[");
                for (int i = 0; i < table.Rows.Count; i++)
                {
                    jsonString.Append("{");
                    for (int j = 0; j < table.Columns.Count; j++)
                    {
                        if (j < table.Columns.Count - 1)
                        {
                            jsonString.Append(""" + table.Columns[j].ColumnName.ToString()
                         + "":" + """
                         + table.Rows[i][j].ToString() + "",");
                        }
                        else if (j == table.Columns.Count - 1)
                        {
                            jsonString.Append(""" + table.Columns[j].ColumnName.ToString()
                         + "":" + """
                         + table.Rows[i][j].ToString() + """);
                        }
                    }
                    if (i == table.Rows.Count - 1)
                    {
                        jsonString.Append("}");
                    }
                    else
                    {
                        jsonString.Append("},");
                    }
                }
                jsonString.Append("]");
            }
            return jsonString.ToString();
        }

2.List To DataTable

/// <summary>
        /// List转换成DataTable
        /// </summary>
        /// <param name="list"></param>
        /// <returns></returns>
        public static System.Data.DataTable ListToDataTable(IList list)
        {
            System.Data.DataTable result = new System.Data.DataTable();
            if (list.Count > 0)
            {
                PropertyInfo[] propertys = list[0].GetType().GetProperties();
                foreach (PropertyInfo pi in propertys)
                {
                    //获取类型
                    Type colType = pi.PropertyType;
                    //当类型为Nullable<>时
                    if ((colType.IsGenericType) && (colType.GetGenericTypeDefinition() == typeof(Nullable<>)))
                    {
                        colType = colType.GetGenericArguments()[0];
                    }
                    result.Columns.Add(pi.Name, colType);
                }
                for (int i = 0; i < list.Count; i++)
                {
                    ArrayList tempList = new ArrayList();
                    foreach (PropertyInfo pi in propertys)
                    {
                        object obj = pi.GetValue(list[i], null);
                        tempList.Add(obj);
                    }
                    object[] array = tempList.ToArray();
                    result.LoadDataRow(array, true);
                }
            }
            return result;
        }

 3.DataTable To List

public static List<T> DataTableToList<T>(DataTable table) where T : class, new()
        {
            // 定义集合 
            List<T> ts = new List<T>();
            if (table.Rows.Count>0)
            {
                //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 table.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 (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 (table.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;
        }