StringLength vs MaxLength attributes ASP NET MVC with Entity Framework EF Code First

Question

What is the difference in behavior of  MaxLength  and  StringLength  attributes   As far as I can tell  with the exception that  MaxLength  can validate the maximum length of an array  these are identical and somewhat redundant

User · Answer

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

User · Answer

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

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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

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I have resolved it by adding below line in my context   modelBuilder Entity lt YourObject gt    Property e   gt  e YourColumn  HasMaxLength 4000     Somehow   MaxLength  didn t work for me

User · Answer

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

User · Answer

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

User · Answer

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     0    Property Name   1    Max Length   2    Min Length   Much thanks to bloudraak for initially pointing this out

User · Answer

When using the attribute to restrict the maximum input length for text from a form on a webpage  the StringLength seems to generate the maxlength html attribute  at least in my test with MVC 5   The one to choose then depnds on how you want to alert the user that this is the maximum text length  With the stringlength attribute  the user will simply not be able to type beyond the allowed length  The maxlength attribute doesn t add this html attribute  instead it generates data validation attributes  meaning the user can type beyond the indicated length and that preventing longer input depends on the validation in javascript when he moves to the next field or clicks submit  or if javascript is disabled  server side validation   In this case the user can be notified of the restriction by an error message

[asp.net-mvc-3] StringLength vs MaxLength attributes ASP.NET MVC with Entity Framework EF Code First

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