为什么DataAnnotation MaxLength（8192）不起作用？

Question

I am working on a project with Entity Framework 6.1.3 in C#, and I want to set an maximum limit on some binary data.

[MaxLength(8192)] does not work is this a bug? There seems to be an upper limit to it.

[MaxLength(4096)] this works surprisingly?

Am I using DataAnnotations correctly?

//[MaxLength(4096)] <-- this works
[MaxLength(8192)]
public Byte[] MediaData {get; set;}

Result:

MediaData = c.Binary()

Expected:

MediaData = c.Binary(maxLength: )

Also tried.

[MaxLength(8192)]    // this does not work either
public string Text {get; set;}

I could fix it manually but It annoys me that DataAnnotations does not work automatically. What are your experiences/recommendations with DataAnnotations?

Answer 1

from MSDN, look at the bold part :D

for string part:

nvarchar [ ( n | max ) ] Variable-length Unicode string data. n defines the string length and can be a value from 1 through 4,000 . max indicates that the maximum storage size is 2^31-1 bytes (2 GB). The storage size, in bytes, is two times the actual length of data entered + 2 bytes. The ISO synonyms for nvarchar are national char varying and national character varying.

and for the binary part:

varbinary [ ( n | max) ] Variable-length binary data. n can be a value from 1 through 8,000. max indicates that the maximum storage size is 2^31-1 bytes. The storage size is the actual length of the data entered + 2 bytes. The data that is entered can be 0 bytes in length. The ANSI SQL synonym for varbinary is binary varying.

so there is actually a limitation here.