class/System.ComponentModel.DataAnnotations/System.ComponentModel.DataAnnotations/ValidationAttribute.cs

   1 //
   2 // ValidationAttribute.cs
   3 //
   4 // Authors:
   5 //      Atsushi Enomoto <atsushi@ximian.com>
   6 //      Marek Habersack <mhabersack@novell.com>
   7 //
   8 // Copyright (C) 2008-2010 Novell Inc. http://novell.com
   9 //
  10
  11 //
  12 // Permission is hereby granted, free of charge, to any person obtaining
  13 // a copy of this software and associated documentation files (the
  14 // "Software"), to deal in the Software without restriction, including
  15 // without limitation the rights to use, copy, modify, merge, publish,
  16 // distribute, sublicense, and/or sell copies of the Software, and to
  17 // permit persons to whom the Software is furnished to do so, subject to
  18 // the following conditions:
  19 //
  20 // The above copyright notice and this permission notice shall be
  21 // included in all copies or substantial portions of the Software.
  22 //
  23 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  27 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  28 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  29 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  30 //
  31 using System;
  32 using System.ComponentModel;
  33 using System.Reflection;
  34
  35 namespace System.ComponentModel.DataAnnotations
  36 {
  37         public abstract class ValidationAttribute : Attribute
  38         {
  39                 const string DEFAULT_ERROR_MESSAGE = "The field {0} is invalid.";
  40 #if !NET_4_0
  41                 string errorMessage;
  42                 string errorMessageResourceName;
  43                 string errorMessageString;
  44                 Type errorMessageResourceType;
  45 #endif
  46                 string fallbackErrorMessage;
  47                 Func <string> errorMessageAccessor;
  48
  49                 protected ValidationAttribute ()
  50                 {
  51                 }
  52
  53                 protected ValidationAttribute (Func<string> errorMessageAccessor)
  54                 {
  55                         this.errorMessageAccessor = errorMessageAccessor;
  56                 }
  57
  58                 protected ValidationAttribute (string errorMessage)
  59                 {
  60                         fallbackErrorMessage = errorMessage;
  61                 }
  62
  63                 public virtual string FormatErrorMessage (string name)
  64                 {
  65                         return String.Format (ErrorMessageString, name);
  66                 }
  67 #if NET_4_0
  68                 public string ErrorMessage { get; set; }
  69                 public string ErrorMessageResourceName { get; set; }
  70                 public Type ErrorMessageResourceType { get; set; }
  71 #else
  72                 public string ErrorMessage {
  73                         get { return errorMessage; }
  74
  75                         set {
  76                                 if (errorMessage != null)
  77                                         throw new InvalidOperationException ("This property can be set only once.");
  78
  79                                 if (String.IsNullOrEmpty (value))
  80                                         throw new ArgumentException ("Value cannot be null or empty.", "value");
  81
  82                                 if (errorMessageResourceName != null || errorMessageResourceType != null)
  83                                         throw new InvalidOperationException ("This property cannot be set because the attribute is already in the resource mode.");
  84
  85                                 errorMessage = value;
  86                         }
  87                 }
  88
  89                 public string ErrorMessageResourceName {
  90                         get { return errorMessageResourceName; }
  91
  92                         set {
  93                                 if (errorMessageResourceName != null)
  94                                         throw new InvalidOperationException ("This property can be set only once.");
  95
  96                                 if (String.IsNullOrEmpty (value))
  97                                         throw new ArgumentException ("Value cannot be null or empty.", "value");
  98
  99                                 errorMessageResourceName = value;
 100                                 if (errorMessageResourceType != null)
 101                                         errorMessageString = GetStringFromResourceAccessor ();
 102                         }
 103                 }
 104
 105                 public Type ErrorMessageResourceType {
 106                         get { return errorMessageResourceType; }
 107                         set {
 108                                 errorMessageResourceType = value;
 109                                 if (!String.IsNullOrEmpty (errorMessageResourceName))
 110                                         errorMessageString = GetStringFromResourceAccessor ();
 111                         }
 112                 }
 113 #endif
 114                 protected string ErrorMessageString {
 115                         get {
 116 #if NET_4_0
 117                                 return GetStringFromResourceAccessor ();
 118 #else
 119                                 return errorMessageString;
 120 #endif
 121                         }
 122                 }
 123 #if NET_4_0
 124                 public virtual bool IsValid (object value)
 125                 {
 126                         throw new NotImplementedException ("IsValid(object value) has not been implemented by this class.  The preferred entry point is GetValidationResult() and classes should override IsValid(object value, ValidationContext context).");
 127                 }
 128
 129                 protected virtual ValidationResult IsValid (object value, ValidationContext validationContext)
 130                 {
 131                         // .NET emulation
 132                         if (validationContext == null)
 133                                 throw new NullReferenceException (".NET emulation.");
 134
 135                         if (!IsValid (value)) {
 136                                 string memberName = validationContext.MemberName;
 137                                 return new ValidationResult (FormatErrorMessage (validationContext.DisplayName), memberName != null ? new string[] { memberName } : new string[] {});
 138                         }
 139
 140                         return ValidationResult.Success;
 141                 }
 142 #else
 143                 public abstract bool IsValid (object value);
 144 #endif
 145
 146 #if NET_4_0
 147                 public ValidationResult GetValidationResult (object value, ValidationContext validationContext)
 148                 {
 149                         if (validationContext == null)
 150                                 throw new ArgumentNullException ("validationContext");
 151
 152                         ValidationResult ret = IsValid (value, validationContext);
 153                         if (ret != null && String.IsNullOrEmpty (ret.ErrorMessage))
 154                                 ret.ErrorMessage = FormatErrorMessage (validationContext.DisplayName);
 155
 156                         return ret;
 157                 }
 158 #endif
 159                 string GetStringFromResourceAccessor ()
 160                 {
 161                         string resourceName = ErrorMessageResourceName;
 162                         Type resourceType = ErrorMessageResourceType;
 163                         string errorMessage = ErrorMessage;
 164
 165                         if (resourceName != null && errorMessage != null)
 166                                 throw new InvalidOperationException ("Either ErrorMessage or ErrorMessageResourceName must be set, but not both.");
 167
 168                         if (resourceType == null ^ resourceName == null)
 169                                 throw new InvalidOperationException ("Both ErrorMessageResourceType and ErrorMessageResourceName must be set on this attribute.");
 170
 171                         if (errorMessageAccessor != null)
 172                                 return errorMessageAccessor ();
 173
 174                         if (resourceType != null) {
 175                                 PropertyInfo pi = resourceType.GetProperty (resourceName, BindingFlags.Public | BindingFlags.Static);
 176                                 if (pi == null || !pi.CanRead)
 177                                         throw new InvalidOperationException (
 178                                                 String.Format ("Resource type '{0}' does not have an accessible static property named '{1}'.",
 179                                                                resourceType, resourceName)
 180                                         );
 181
 182                                 if (pi.PropertyType != typeof (string))
 183                                         throw new InvalidOperationException (
 184                                                 String.Format ("The property '{0}' on resource type '{1}' is not a string type.",
 185                                                                resourceName, resourceType)
 186                                         );
 187
 188                                 return pi.GetValue (null, null) as string;
 189                         }
 190
 191                         if (errorMessage == null)
 192                                 if (fallbackErrorMessage != null)
 193                                         return fallbackErrorMessage;
 194                                 else
 195                                         return DEFAULT_ERROR_MESSAGE;
 196
 197                         return errorMessage;
 198                 }
 199 #if NET_4_0
 200                 public void Validate (object value, ValidationContext validationContext)
 201                 {
 202                         if (validationContext == null)
 203                                 throw new ArgumentNullException ("validationContext");
 204
 205                         ValidationResult result = IsValid (value, validationContext);
 206                         if (result != null) {
 207                                 string message = result.ErrorMessage;
 208                                 if (message == null)
 209                                         message = FormatErrorMessage (validationContext.DisplayName);
 210
 211                                 throw new ValidationException (message, this, value);
 212                         }
 213                 }
 214 #endif
 215                 public void Validate (object value, string name)
 216                 {
 217                         if (!IsValid (value))
 218                                 throw new ValidationException (FormatErrorMessage (name), this, value);
 219                 }
 220         }
 221 }