C# 集合转换为DataTable

该类就用了几个类型，如int，int?，string，所以其它类型就先没管。

用到的类：

    public class tb_Projects
    {

        public int ProID { get; set; }
        public string ProjectName { get; set; }
        /// <summary>
        /// 编码
        /// </summary>
        public string ProjectCode { get; set; }

        public int ParentId { get; set; }
        public int? NextId { get; set; }
        public int? ProjectOrder { get; set; }

        public int IsEnabled { get; set; }
        /// <summary>
        /// 业主单位id
        /// </summary>
        public int? OwnerId { get; set; }
        /// <summary>
        /// 施工单位ID
        /// </summary>
        public int? ConstructionId { get; set; }
        /// <summary>
        /// 监理单位id
        /// </summary>
        public int? SupervisionId { get; set; }
        /// <summary>
        /// 承包单位id
        /// </summary>
        public int? ContractId { get; set; }

        /// <summary>
        /// 第几级（即在树层次中第几级，根元素级次为1，以此类推）
        /// </summary>
        public int? Level { get; set; }
        /// <summary>
        /// 数量
        /// </summary>
        public int? Quantity { get; set; }

        public int VersionIng { get; set; }

        /// <summary>
        /// 里程桩号
        /// </summary>
        public string MileageNo { get; set; }
        /// <summary>
        /// 标准编码
        /// </summary>
        public string ComponentCode { get; set; }

        /// <summary>
        /// 内部编码
        /// </summary>
        public string NComponentCode { get; set; }

        /// <summary>
        /// 流程状态
        /// </summary>
        public int TaskStatus { get; set; }

        public string FbxId { get; set; }
        /// <summary>
        /// 判断是否为单位工程
        /// </summary>
        public int IsSubunit { get; set; }
        /// <summary>
        /// 所属标段
        /// </summary>
        public string BiDSion { get; set; }
    }

代码1：

StringBuilder sb = new StringBuilder();
                Type elementType = typeof(Models.tb_Projects);
                elementType.GetProperties().ToList().ForEach(propInfo =>
                {
                    if (Nullable.GetUnderlyingType(propInfo.PropertyType) == null)
                    {
                        //普通类型
                        Type t = propInfo.PropertyType;
                        if (t == typeof(System.String))
                        { sb.Append($"if(!string.IsNullOrWhiteSpace(item.{propInfo.Name})){{row[\"{propInfo.Name}\"]=item.{propInfo.Name};}}\r\n"); }
                        else
                        { sb.Append($"row[\"{propInfo.Name}\"]=item.{propInfo.Name};\r\n"); }
                    }
                    else
                    {
                        //可为空类型
                        Type t = Nullable.GetUnderlyingType(propInfo.PropertyType);
                        if (t == typeof(System.String))
                        { sb.Append($"if(!string.IsNullOrWhiteSpace(item.{propInfo.Name})){{row[\"{propInfo.Name}\"]=item.{propInfo.Name};}}\r\n"); }
                        else
                        { sb.Append($"if(item.{propInfo.Name}!=null){{row[\"{propInfo.Name}\"]=item.{propInfo.Name};}}\r\n"); }
                    }
                });
                System.IO.File.WriteAllText("2.txt", sb.ToString());
                Console.ReadLine();

代码2：

        public DataTable GetDataTable(List<tb_Projects> list)
        {
            DataTable dt = new DataTable(TableName);
            Type elementType = typeof(tb_Projects);
            elementType.GetProperties().ToList().ForEach(propInfo => dt.Columns.Add(propInfo.Name, Nullable.GetUnderlyingType(propInfo.PropertyType) ?? propInfo.PropertyType));

            list = list.OrderBy(c => c.ProID).ToList();
            list.ForEach(item =>
            {
                DataRow row = dt.NewRow();

                #region 生成赋值语句

                //StringBuilder sb = new StringBuilder();
                //Type elementType = typeof(Models.tb_Projects);
                //elementType.GetProperties().ToList().ForEach(propInfo =>
                //{
                //    if (Nullable.GetUnderlyingType(propInfo.PropertyType) == null)
                //    {
                //        //普通类型
                //        Type t = propInfo.PropertyType;
                //        if (t == typeof(System.String))
                //        { sb.Append($"if(!string.IsNullOrWhiteSpace(item.{propInfo.Name})){{row[\"{propInfo.Name}\"]=item.{propInfo.Name};}}\r\n"); }
                //        else
                //        { sb.Append($"row[\"{propInfo.Name}\"]=item.{propInfo.Name};\r\n"); }
                //    }
                //    else
                //    {
                //        //可为空类型
                //        Type t = Nullable.GetUnderlyingType(propInfo.PropertyType);
                //        if (t == typeof(System.String))
                //        { sb.Append($"if(!string.IsNullOrWhiteSpace(item.{propInfo.Name})){{row[\"{propInfo.Name}\"]=item.{propInfo.Name};}}\r\n"); }
                //        else
                //        { sb.Append($"if(item.{propInfo.Name}!=null){{row[\"{propInfo.Name}\"]=item.{propInfo.Name};}}\r\n"); }
                //    }
                //});
                //System.IO.File.WriteAllText("2.txt", sb.ToString());
                //Console.ReadLine(); 

                //row["ProID"] = item.ProID;
                //row["ProjectName"] = item.ProjectName;
                //row["ParentId"] = item.ParentId;
                //row["Level"] = item.Level;
                //row["BiDSion"] = item.BiDSion;
                //row["VersionIng"] = item.VersionIng;
                //row["MileageNo"] = item.MileageNo;
                //row["ProjectOrder"] = item.ProjectOrder;
                //row["ProjectCode"] = item.ProjectCode;
                //row["NComponentCode"] = item.NComponentCode;
                //row["NEXTID"] = 0;
                //row["ISENABLED"] = 0;

                #endregion

                //默认值 赋空
                elementType.GetProperties().ToList().ForEach(propInfo => row[propInfo.Name] = DBNull.Value);

                //不为空 赋值
                row["ProID"] = item.ProID;
                if (!string.IsNullOrWhiteSpace(item.ProjectName)) { row["ProjectName"] = item.ProjectName; }
                if (!string.IsNullOrWhiteSpace(item.ProjectCode)) { row["ProjectCode"] = item.ProjectCode; }
                row["ParentId"] = item.ParentId;
                if (item.NextId != null) { row["NextId"] = item.NextId; }
                if (item.ProjectOrder != null) { row["ProjectOrder"] = item.ProjectOrder; }
                row["IsEnabled"] = item.IsEnabled;
                if (item.OwnerId != null) { row["OwnerId"] = item.OwnerId; }
                if (item.ConstructionId != null) { row["ConstructionId"] = item.ConstructionId; }
                if (item.SupervisionId != null) { row["SupervisionId"] = item.SupervisionId; }
                if (item.ContractId != null) { row["ContractId"] = item.ContractId; }
                if (item.Level != null) { row["Level"] = item.Level; }
                if (item.Quantity != null) { row["Quantity"] = item.Quantity; }
                row["VersionIng"] = item.VersionIng;
                if (!string.IsNullOrWhiteSpace(item.MileageNo)) { row["MileageNo"] = item.MileageNo; }
                if (!string.IsNullOrWhiteSpace(item.ComponentCode)) { row["ComponentCode"] = item.ComponentCode; }
                if (!string.IsNullOrWhiteSpace(item.NComponentCode)) { row["NComponentCode"] = item.NComponentCode; }
                row["TaskStatus"] = item.TaskStatus;
                if (!string.IsNullOrWhiteSpace(item.FbxId)) { row["FbxId"] = item.FbxId; }
                row["IsSubunit"] = item.IsSubunit;
                if (!string.IsNullOrWhiteSpace(item.BiDSion)) { row["BiDSion"] = item.BiDSion; }

                //初值 仅这里使用
                row["NextId"] = ;
                row["IsEnabled"] = ;

                dt.Rows.Add(row);
            });

            return dt;
        }