mcs/class/Managed.Windows.Forms/System.Windows.Forms/Binding.cs

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   6 // permit persons to whom the Software is furnished to do so, subject to
   7 // the following conditions:
   8 //
   9 // The above copyright notice and this permission notice shall be
  10 // included in all copies or substantial portions of the Software.
  11 //
  12 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  13 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  14 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  15 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  16 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  17 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  18 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  19 //
  20 // Copyright (c) 2004-2005 Novell, Inc.
  21 //
  22 // Authors:
  23 //      Peter Bartok    pbartok@novell.com
  24 //      Jackson Harper  jackson@ximian.com
  25 //
  26
  27
  28 using System.ComponentModel;
  29
  30 namespace System.Windows.Forms {
  31
  32         [TypeConverter (typeof (ListBindingConverter))]
  33         public class Binding {
  34
  35                 private string property_name;
  36                 private object data_source;
  37                 private string data_member;
  38                 private BindingMemberInfo binding_member_info;
  39                 private Control control;
  40
  41                 private BindingManagerBase manager;
  42                 private PropertyDescriptor prop_desc;
  43                 private object data;
  44
  45                 private EventDescriptor changed_event;
  46                 private EventHandler property_value_changed_handler;
  47                 private object event_current; // The manager.Current as far as the changed_event knows
  48
  49                 #region Public Constructors
  50                 public Binding (string propertyName, object dataSource, string dataMember)
  51                 {
  52                         property_name = propertyName;
  53                         data_source = dataSource;
  54                         data_member = dataMember;
  55                         binding_member_info = new BindingMemberInfo (dataMember);
  56                 }
  57                 #endregion      // Public Constructors
  58
  59                 #region Public Instance Properties
  60                 public BindingManagerBase BindingManagerBase {
  61                         get {
  62                                 return manager;
  63                         }
  64                 }
  65
  66                 public BindingMemberInfo BindingMemberInfo {
  67                         get {
  68                                 return binding_member_info;
  69                         }
  70                 }
  71
  72                 [DefaultValue (null)]
  73                 public Control Control {
  74                         get {
  75                                 return control;
  76                         }
  77                 }
  78
  79                 public object DataSource {
  80                         get {
  81                                 return data_source;
  82                         }
  83                 }
  84
  85                 [MonoTODO]
  86                 public bool IsBinding {
  87                         get {
  88                                 return false;
  89                         }
  90                 }
  91
  92                 [DefaultValue ("")]
  93                 public string PropertyName {
  94                         get {
  95                                 return property_name;
  96                         }
  97                 }
  98                 #endregion      // Public Instance Properties
  99
 100                 #region Protected Instance Methods
 101                 protected virtual void OnFormat (ConvertEventArgs cevent)
 102                 {
 103                         if (Format!=null)
 104                                 Format (this, cevent);
 105                 }
 106
 107                 protected virtual void OnParse (ConvertEventArgs cevent)
 108                 {
 109                         if (Parse!=null)
 110                                 Parse (this, cevent);
 111                 }
 112                 #endregion      // Protected Instance Methods
 113
 114
 115                 internal void SetControl (Control control)
 116                 {
 117                         if (control == this.control)
 118                                 return;
 119
 120                         prop_desc = TypeDescriptor.GetProperties (control).Find (property_name, false);
 121
 122                         if (prop_desc == null)
 123                                 throw new ArgumentException (String.Concat ("Cannot bind to property '", property_name, "' on target control."));
 124                         if (prop_desc.IsReadOnly)
 125                                 throw new ArgumentException (String.Concat ("Cannot bind to property '", property_name, "' because it is read only."));
 126                         this.control = control;
 127                 }
 128
 129                 internal void Check (BindingContext binding_context)
 130                 {
 131                         if (control == null)
 132                                 return;
 133
 134                         manager = control.BindingContext [data_source, property_name];
 135                         manager.AddBinding (this);
 136
 137                         WirePropertyValueChangedEvent ();
 138
 139                         PullData ();
 140                         PushData ();
 141                 }
 142
 143                 internal void PushData ()
 144                 {
 145                         prop_desc.SetValue (control, data);
 146                 }
 147
 148                 internal void PullData ()
 149                 {
 150                         PropertyDescriptor pd = TypeDescriptor.GetProperties (manager.Current).Find (data_member, true);
 151                         data = pd.GetValue (manager.Current);
 152                 }
 153
 154                 internal void UpdateIsBinding ()
 155                 {
 156                         PushData ();
 157                 }
 158
 159                 private void CurrentChangedHandler ()
 160                 {
 161                         if (changed_event != null) {
 162                                 changed_event.RemoveEventHandler (event_current, property_value_changed_handler);
 163                                 WirePropertyValueChangedEvent ();
 164                         }
 165                 }
 166
 167                 private void WirePropertyValueChangedEvent ()
 168                 {
 169                         EventDescriptor changed_event = TypeDescriptor.GetEvents (manager.Current).Find (property_name + "Changed", false);
 170                         if (changed_event == null)
 171                                 return;
 172                         property_value_changed_handler = new EventHandler (PropertyValueChanged);
 173                         changed_event.AddEventHandler (manager.Current, property_value_changed_handler);
 174
 175                         event_current = manager.Current;
 176                 }
 177
 178                 private void PropertyValueChanged (object sender, EventArgs e)
 179                 {
 180                         PullData ();
 181                         PushData ();
 182                 }
 183
 184                 #region Events
 185                 public event ConvertEventHandler Format;
 186                 public event ConvertEventHandler Parse;
 187                 #endregion      // Events
 188         }
 189 }