mcs/class/System.Web/System.Web.UI.WebControls/Parameter.cs

   1 //
   2 // System.Web.UI.WebControls.Parameter
   3 //
   4 // Authors:
   5 //      Ben Maurer (bmaurer@users.sourceforge.net)
   6 //      Sanjay Gupta (gsanjay@novell.com)
   7 //
   8 // (C) 2003 Ben Maurer
   9 // (C) 2004 Novell, Inc. (http://www.novell.com)
  10 //
  11
  12 //
  13 // Permission is hereby granted, free of charge, to any person obtaining
  14 // a copy of this software and associated documentation files (the
  15 // "Software"), to deal in the Software without restriction, including
  16 // without limitation the rights to use, copy, modify, merge, publish,
  17 // distribute, sublicense, and/or sell copies of the Software, and to
  18 // permit persons to whom the Software is furnished to do so, subject to
  19 // the following conditions:
  20 //
  21 // The above copyright notice and this permission notice shall be
  22 // included in all copies or substantial portions of the Software.
  23 //
  24 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  28 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  29 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  30 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  31 //
  32
  33 #if NET_2_0
  34 using System.Collections;
  35 using System.Collections.Specialized;
  36 using System.Text;
  37 using System.Data;
  38 using System.ComponentModel;
  39
  40 namespace System.Web.UI.WebControls {
  41         [DefaultPropertyAttribute ("DefaultValue")]
  42         public class Parameter : ICloneable, IStateManager
  43         {
  44                 public Parameter () : base ()
  45                 {
  46                 }
  47
  48                 protected Parameter (Parameter original)
  49                 {
  50                         this.DefaultValue = original.DefaultValue;
  51                         this.Direction = original.Direction;
  52                         this.ConvertEmptyStringToNull = original.ConvertEmptyStringToNull;
  53                         this.Type = original.Type;
  54                         this.Name = original.Name;
  55                 }
  56
  57                 public Parameter (string name)
  58                 {
  59                         this.Name = name;
  60                 }
  61
  62                 public Parameter(string name, TypeCode type) : this (name)
  63                 {
  64                         this.Type = type;
  65                 }
  66
  67                 public Parameter (string name, TypeCode type, string defaultValue) : this (name, type)
  68                 {
  69                         this.DefaultValue = defaultValue;
  70                 }
  71
  72                 protected virtual Parameter Clone ()
  73                 {
  74                         return new Parameter (this);
  75                 }
  76
  77                 protected void OnParameterChanged ()
  78                 {
  79                         if (_owner != null)
  80                                 _owner.CallOnParameterChanged ();
  81                 }
  82
  83                 protected virtual void LoadViewState (object savedState)
  84                 {
  85                         ViewState.LoadViewState (savedState);
  86                 }
  87
  88                 protected virtual object SaveViewState ()
  89                 {
  90                         return ViewState.SaveViewState ();
  91                 }
  92
  93                 protected virtual void TrackViewState ()
  94                 {
  95                         isTrackingViewState = true;
  96                         if (viewState != null)
  97                                 viewState.TrackViewState ();
  98                 }
  99
 100                 object ICloneable.Clone ()
 101                 {
 102                         return this.Clone ();
 103                 }
 104
 105                 void IStateManager.LoadViewState (object savedState)
 106                 {
 107                         this.LoadViewState (savedState);
 108                 }
 109
 110                 object IStateManager.SaveViewState ()
 111                 {
 112                         return this.SaveViewState ();
 113                 }
 114
 115                 void IStateManager.TrackViewState ()
 116                 {
 117                         this.TrackViewState ();
 118                 }
 119
 120                 bool IStateManager.IsTrackingViewState {
 121                         get { return this.IsTrackingViewState; }
 122                 }
 123
 124                 // MSDN: The ToString method returns the Name property of the Parameter object. If the Parameter object has no name, ToString returns String.Empty.
 125                 public override string ToString ()
 126                 {
 127                         return Name;
 128                 }
 129
 130                 [WebCategoryAttribute ("Parameter")]
 131                 [DefaultValueAttribute (null)]
 132                 [WebSysDescriptionAttribute ("Default value to be used in case value is null.")]
 133                 public string DefaultValue {
 134                         get { return ViewState.GetString ("DefaultValue", null); }
 135                         set {
 136
 137                                 if (DefaultValue != value) {
 138                                         ViewState ["DefaultValue"] = value;
 139                                         OnParameterChanged ();
 140                                 }
 141                         }
 142                 }
 143
 144                 [WebCategoryAttribute ("Parameter")]
 145                 [DefaultValueAttribute ("Input")]
 146                 [WebSysDescriptionAttribute ("Parameter's direction.")]
 147                 public ParameterDirection Direction
 148                 {
 149                         get { return (ParameterDirection) ViewState.GetInt ("Direction", (int)ParameterDirection.Input); }
 150                         set {
 151                                 if (Direction != value) {
 152                                         ViewState ["Direction"] = value;
 153                                         OnParameterChanged ();
 154                                 }
 155                         }
 156                 }
 157
 158
 159                 [WebCategoryAttribute ("Parameter")]
 160                 [DefaultValueAttribute ("")]
 161                 [WebSysDescriptionAttribute ("Parameter's name.")]
 162                 public string Name
 163                 {
 164                         get {
 165                                 string s = ViewState ["Name"] as string;
 166                                 if (s != null)
 167                                         return s;
 168
 169                                 return "";
 170                         }
 171                         set {
 172
 173                                 if (Name != value) {
 174                                         ViewState ["Name"] = value;
 175                                         OnParameterChanged ();
 176                                 }
 177                         }
 178                 }
 179
 180                 [WebCategoryAttribute ("Parameter")]
 181                 [DefaultValueAttribute (true)]
 182                 [WebSysDescriptionAttribute ("Checks whether an empty string is treated as a null value.")]
 183                 public bool ConvertEmptyStringToNull
 184                 {
 185                         get { return ViewState.GetBool ("ConvertEmptyStringToNull", true); }
 186                         set {
 187                                 if (ConvertEmptyStringToNull != value) {
 188                                         ViewState["ConvertEmptyStringToNull"] = value;
 189                                         OnParameterChanged ();
 190                                 }
 191                         }
 192                 }
 193
 194                 [DefaultValue (0)]
 195                 public int Size {
 196                         get { return ViewState.GetInt ("Size", 0); }
 197                         set {
 198                                 if (Size != value) {
 199                                         ViewState["Size"] = value;
 200                                         OnParameterChanged ();
 201                                 }
 202                         }
 203                 }
 204
 205                 [DefaultValueAttribute (TypeCode.Empty)]
 206                 [WebCategoryAttribute ("Parameter"),
 207                 WebSysDescriptionAttribute("Represents type of the parameter.")]
 208                 public TypeCode Type
 209                 {
 210                         get { return (TypeCode) ViewState.GetInt ("Type", (int)TypeCode.Empty); }
 211                         set {
 212
 213                                 if (Type != value) {
 214                                         ViewState ["Type"] = value;
 215                                         OnParameterChanged ();
 216                                 }
 217                         }
 218                 }
 219
 220                 StateBag viewState;
 221                 [BrowsableAttribute (false),
 222                 DesignerSerializationVisibilityAttribute (DesignerSerializationVisibility.Hidden)]
 223                 protected StateBag ViewState {
 224                         get {
 225                                 if (viewState == null) {
 226                                         viewState = new StateBag ();
 227                                         if (IsTrackingViewState)
 228                                                 viewState.TrackViewState ();
 229                                 }
 230                                 return viewState;
 231                         }
 232                 }
 233
 234                 bool isTrackingViewState = false;
 235                 protected bool IsTrackingViewState {
 236                         get { return isTrackingViewState; }
 237                 }
 238
 239                 // MSDN: The default implementation of the Evaluate method is to return
 240                 // a null reference (Nothing in Visual Basic) in all cases.
 241                 // Classes that derive from the Parameter class override the Evaluate method
 242                 // to return an updated parameter value. For example, the ControlParameter object
 243                 // returns the value of the control that it is bound to, while
 244                 // the QueryStringParameter object retrieves the current name/value pair from
 245                 // the HttpRequest object.
 246                 protected virtual object Evaluate (HttpContext context, Control control)
 247                 {
 248                         return null;
 249                 }
 250
 251                 internal void UpdateValue (HttpContext context, Control control)
 252                 {
 253                         object oldValue = ViewState ["ParameterValue"];
 254
 255                         object newValue = Evaluate (context, control);
 256
 257                         if (!object.Equals (oldValue, newValue)) {
 258                                 ViewState ["ParameterValue"] = newValue;
 259                                 OnParameterChanged ();
 260                         }
 261                 }
 262
 263                 internal object GetValue (HttpContext context, Control control)
 264                 {
 265                         UpdateValue (context, control);
 266
 267                         object value = ConvertValue (ViewState ["ParameterValue"]);
 268                         if (value == null)
 269                                 value = ConvertValue (DefaultValue);
 270
 271                         return value;
 272                 }
 273
 274                 internal object ConvertValue (object val)
 275                 {
 276                         if (val == null) return null;
 277                         if (ConvertEmptyStringToNull && val.Equals (string.Empty))
 278                                 return null;
 279                         return Type != TypeCode.Empty ? Convert.ChangeType (val, Type) : val;
 280                 }
 281
 282                 protected internal virtual void SetDirty()
 283                 {
 284                         ViewState.SetDirty (true);
 285                 }
 286
 287                 ParameterCollection _owner;
 288                 internal void SetOwnerCollection (ParameterCollection own)
 289                 {
 290                         _owner = own;
 291                 }
 292         }
 293 }
 294 #endif
 295