MaxLength is used for the Entity Framework to decide how large to make a string value field when it creates the database.
From MSDN:
Specifies the maximum length of array or string data allowed in a property.
StringLength is a data annotation that will be used for validation of user input.
From MSDN:
Specifies the minimum and maximum length of characters that are allowed in a data field.
Some quick but extremely useful additional information that I just learned from another post, but can't seem to find the documentation for (if anyone can share a link to it on MSDN that would be amazing):
The validation messages associated with these attributes will actually replace placeholders associated with the attributes. For example:
[MaxLength(100, "{0} can have a max of {1} characters")]
public string Address { get; set; }
Will output the following if it is over the character limit: "Address can have a max of 100 characters"
The placeholders I am aware of are:
Much thanks to bloudraak for initially pointing this out.
Following are the results when we use both [MaxLength]
and [StringLength]
attributes, in EF code first
. If both are used, [MaxLength]
wins the race. See the test result in studentname
column in below class
public class Student
{
public Student () {}
[Key]
[Column(Order=1)]
public int StudentKey { get; set; }
//[MaxLength(50),StringLength(60)] //studentname column will be nvarchar(50)
//[StringLength(60)] //studentname column will be nvarchar(60)
[MaxLength(50)] //studentname column will be nvarchar(50)
public string StudentName { get; set; }
[Timestamp]
public byte[] RowVersion { get; set; }
}
All good answers...From the validation perspective, I also noticed that MaxLength gets validated at the server side only, while StringLength gets validated at client side too.
One another point to note down is in MaxLength attribute you can only provide max required range not a min required range. While in StringLength you can provide both.
MaxLengthAttribute means Max. length of array or string data allowed
StringLengthAttribute means Min. and max. length of characters that are allowed in a data field
Visit http://joeylicc.wordpress.com/2013/06/20/asp-net-mvc-model-validation-using-data-annotations/
I have resolved it by adding below line in my context:
modelBuilder.Entity<YourObject>().Property(e => e.YourColumn).HasMaxLength(4000);
Somehow, [MaxLength]
didn't work for me.
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