C# How to use DataAnnotations StringLength and SubString to remove text

Question

I have a model classes that has a description property with a data annotation attribute of StringLength and length is set to 100 characters. When this property is more than 100

Answer 1

Why all the hassle? Why not

private string _description = string.Empty;

[StringLength(100, ErrorMessage = "Description Max Length is 100")]
public string Description 
{  
    get { return _description; }
    set { _description = value.Substring(0,100); };  // or something equivalent
}