如何设置NEWID（）为GUID的实体框架 [英] How to set NewId() for GUID in entity framework

问题描述

我创建asp.net mvc4 sample.In这在我的DataContext样表创建ID列GUID。

I am creating asp.net mvc4 sample.In this i created Id column as GUID in Sample table of datacontext.

public class Sample
{
    [Required]
    public Guid ID { get; set; }
    [Required]
    public string FirstName { get; set; }
}

这是实体表

CreateTable(
"dbo.Samples",
 c => new
 {
     ID = c.Guid(nullable: false),
     FirstName = c.String(nullable: false)                   
 })
 .PrimaryKey(t => t.ID);

ID传递00000000-0000-0000-0000-000000000000。

Id pass 00000000-0000-0000-0000-000000000000.

如何设置 NEWID（）到 GUID 并在那里我有设置。

How to set newid() to GUID and where i have to set.

推荐答案

我只想用长为您的ID类型建议。它只是工作与拥有超过GUID一定的性能提升。但是，如果你想使用一个GUID，您应该使用顺序GUID 并设置它在构造函数中。我也将做ID的私人二传手：

I would recommend just using long for your ID type. It "just works" with and has some performance gains over GUID. But if you want to use a GUID, you should use a Sequential GUID and set it in the constructor. I would also make ID a private setter:

public class Sample
{
    public Sample() {
        ID = GuidComb.Generate();
    }
    [Required]
    public Guid ID { get; private set; }
    [Required]
    public string FirstName { get; set; }
}

连续GUID

public static class GuidComb
    {
        public static Guid Generate()
        {
            var buffer = Guid.NewGuid().ToByteArray();

            var time = new DateTime(0x76c, 1, 1);
            var now = DateTime.Now;
            var span = new TimeSpan(now.Ticks - time.Ticks);
            var timeOfDay = now.TimeOfDay;

            var bytes = BitConverter.GetBytes(span.Days);
            var array = BitConverter.GetBytes(
                (long)(timeOfDay.TotalMilliseconds / 3.333333));

            Array.Reverse(bytes);
            Array.Reverse(array);
            Array.Copy(bytes, bytes.Length - 2, buffer, buffer.Length - 6, 2);
            Array.Copy(array, array.Length - 4, buffer, buffer.Length - 4, 4);

            return new Guid(buffer);
        }
    }

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