Nullable<System.DateTime>日期格式转换 （转载）

一、问题

　1、html页面中时间显示出错，数据库中时间是正确的。

   原因：没有把DateTime转成String类型。

　2、  在C#中，发现不能直接使用ToString("yyyy-MM-dd HH:mm")这样的格式进行日期格式转换。

    原因：在DB中，字段设置为Nullable<System.DateTime>，是可空的DateTime类型。

二、解决方案

　　if (user.BirthDate.HasValue)
　　{
　　　　userInfo.BirthDate = user.BirthDate.Value.ToString("yyyy-MM-dd");
　　}else
　　{
　　　　userInfo.BirthDate = string.Empty;
　　}

三、完整案例

public UserInfo GetUserNoPasswordByUserName(string userName)
{

var user= db.T_User.Select(d => new  { Address = d.Address, BirthDate = d.BirthDate, Company = d.Company, Phone = d.Phone, RealName = d.RealName, TelPhone = d.TelPhone, TypeID = d.TypeID, UserID = d.UserID, UserName = d.UserName, UserStatus = d.UserStatus }).Where(d => d.UserName == userName).SingleOrDefault();
UserInfo userInfo = new UserInfo();
userInfo.Address = user.Address;
if (user.BirthDate.HasValue)
{
userInfo.BirthDate =  user.BirthDate.Value.ToString("yyyy-MM-dd");
}else
{
userInfo.BirthDate = string.Empty;
}
userInfo.Company = user.Company;
userInfo.Phone = user.Phone;
userInfo.RealName = user.RealName;
userInfo.TelPhone = user.TelPhone;
userInfo.TypeID = user.TypeID;
userInfo.UserID = user.UserID;
userInfo.UserName = user.UserName;
userInfo.UserStatus = user.UserStatus;

return userInfo;

}

//自定义视图数据类
public class UserInfo
{
public int UserID { get; set; }
public string UserName { get; set; }
public Nullable<short> TypeID { get; set; }
public short UserStatus { get; set; }
// public string Password { get; set; }
public string RealName { get; set; }
public string Company { get; set; }
public string BirthDate { get; set; }
public string Phone { get; set; }
public string TelPhone { get; set; }
public string Address { get; set; }
}

//数据实体类
public partial class T_User
{

public int UserID { get; set; }
public string UserName { get; set; }
public Nullable<short> TypeID { get; set; }
public short UserStatus { get; set; }
public string Password { get; set; }
public string RealName { get; set; }
public string Company { get; set; }
public Nullable<System.DateTime> BirthDate { get; set; }
public string Phone { get; set; }
public string TelPhone { get; set; }
public string Address { get; set; }

}

转载来源：https://blog.csdn.net/baidu_34331194/article/details/68944906