public class GoAMLProperties : ConfigurationElement
    {
        ...
 
        [ConfigurationProperty("nameField", IsRequired = true, DefaultValue = "" )]
        [StringValidator(InvalidCharacters = "~!@#$%^&*()[]{}/;’\"|\\"
          , MinLength = 1
          , MaxLength = 29)]
        public String Name
        {
            get { return (String)this["nameField"]; }
            set { this["name"] = value; }
        }
 
        [ConfigurationProperty("schema_versionField", IsRequired = true, DefaultValue = "" )]
        [StringValidator(InvalidCharacters = "~!@#$%^&*()[]{}/;’\"|\\"
          , MinLength = 0
          , MaxLength = 25)]
        public string schema_version
        {
            get { return (String)this["schema_versionField"]; }
            set { this["schema_versionField"] = value; }
        }
        ...