如何使用Entity Framework将当前日期/时间插入datetime数据类型字段？

Question

I am using Entity Framework to insert a row of data into my Application table.

Here's the class:

public partial class Application
{
    public Application()
    {
        this.TestAccounts = new List<TestAccount>();
    }

    public int ApplicationId { get; set; }
    public string Name { get; set; }
    public byte[] RowVersion { get; set; }
    public System.DateTime ModifiedDate { get; set; }
    public virtual ICollection<TestAccount> TestAccounts { get; set; }
}

Here's the C# code:

_Uow.Applications.Add(new Application { Name = name });

It's giving me an error saying

  InnerException: System.Data.UpdateException
        HResult=-2146233087
        Message=An error occurred while updating the entries. See the inner exception for details.
        Source=System.Data.Entity

        InnerException: System.Data.SqlClient.SqlException
             HResult=-2146232060
             Message=The conversion of a datetime2 data type to a datetime data type
             resulted in an out-of-range value.

How can I change my C# code to insert the current date in the ModifiedDate field?

Answer 1

Simply that way:

_Uow.Applications.Add(new Application
                       {
                           Name = name,
                           ModifiedDate = DateTime.Now
                       });

Or you may do it in the constructor:

public class Application
{
    public Application()
    {
        ModifiedDate = DateTime.Now;
    }
}

By the way: You got the exception because per default c# DateTime is more precise than datetime of SQL. Like the message says: Use datetime2 in SQL. DateTime has it's min value as initial value, which is too low for SQL datetime .

Answer 2

You could specify a new constructor

public Application(string Name)
{
  if(ModifiedDate == null)
   //ModifiedDate = Convert.ToDateTime(01.01.2000);
     ModifiedDate = DateTime.Now;
}

OR

public Application(string Name, System.Nullable<DateTime> modifiedDate)
{
   if(modifiedDate != null)
     //ModifiedDate = Convert.ToDateTime(01.01.2000);
     ModifiedDate = DateTime.Now;
   else
   Do stuff
}

This isn't beatifull, but should do the trick.

Answer 3

hi your ModifiedDate is initialized with minvalue as a result it gives an exception. Better to use either

public System.DateTime? ModifiedDate { get; set; } to make it nullable or

initialize in the construction

public Application()
    {
        this.TestAccounts = new List<TestAccount>();
        ModifiedDate = DateTime.Now;

    }