Bug 2076 - StringLengthAttribute behaviour insconsistent with Microsoft.NET
Summary: StringLengthAttribute behaviour insconsistent with Microsoft.NET
Alias: None
Product: Class Libraries
Classification: Mono
Component: System ()
Version: 2.10.x
Hardware: All All
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
Depends on:
Reported: 2011-11-17 01:26 UTC by Eddy Zavaleta
Modified: 2012-03-12 23:04 UTC (History)
3 users (show)

Is this bug a regression?: ---
Last known good build:

Proposed patch (870 bytes, application/octet-stream)
2011-11-17 01:26 UTC, Eddy Zavaleta

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Description Eddy Zavaleta 2011-11-17 01:26:45 UTC
Created attachment 901 [details]
Proposed patch

I have found that mono's StringLengthAttribute class (System.ComponentModel.DataAnnotations) have an inconsistency for localized error messages. In MS .NET the formatting function (FormatErrorMessage) supports 3 indexed placeholders (field name, maximum length, minimum length) for error message string and mono only supports the first two.

Steps to reproduce the problem:
1. Create an asp.net app with a model using StringLength validation.
2. Use "{2}" inside the ErrorMessage string.
3. Test the validation.

Code snippet:
public class TestModel
    public TestModel()

    [StringLength(10, MinimumLength = 3, ErrorMessage = "{0} must be between {2} and {1} characters.")]
    public string TestProperty { get; set; }

Actual Results:
System.FormatException: Index (zero based) must be greater than or equal to zero and less than the size of the argument list.

Expected Results:
Correct formatted message: "TestProperty must be between 3 and 10 characters."

I have attach a patch that fix the problem.
Comment 1 Anton Heryanto 2011-12-05 05:44:52 UTC
voted this bug to fixed
Comment 2 Miguel de Icaza [MSFT] 2012-03-12 23:04:19 UTC
This is supported if you are using the 4.0 API