mcs/class/System.Data/System.Data/Constraint.cs

   1 //
   2 // System.Data.Constraint.cs
   3 //
   4 // Author:
   5 //      Franklin Wise <gracenote@earthlink.net>
   6 //      Daniel Morgan
   7 //
   8 //
   9 // (C) Ximian, Inc. 2002
  10 //
  11
  12 using System;
  13 using System.Collections;
  14 using System.ComponentModel;
  15 using System.Runtime.InteropServices;
  16 using System.Runtime.Serialization;
  17
  18 namespace System.Data
  19 {
  20         [Serializable]
  21         internal delegate void DelegateConstraintNameChange(object sender,
  22                         string newName);
  23
  24         [Serializable]
  25         public abstract class Constraint
  26         {
  27                 internal event DelegateConstraintNameChange
  28                                         BeforeConstraintNameChange;
  29
  30                 //if constraintName is not set then a name is
  31                 //created when it is added to
  32                 //the ConstraintCollection
  33                 //it can not be set to null, empty or duplicate
  34                 //once it has been added to the collection
  35                 private string _constraintName = null;
  36                 private PropertyCollection _properties = null;
  37
  38                 //Used for membership checking
  39                 private ConstraintCollection _constraintCollection;
  40
  41                 protected Constraint()
  42                 {
  43                         _properties = new PropertyCollection();
  44                 }
  45
  46                 public virtual string ConstraintName {
  47                         get{
  48                                 return "" + _constraintName;
  49                         }
  50
  51                         set{
  52                                 //This should only throw an exception when it
  53                                 //is a member of a ConstraintCollection which
  54                                 //means we should let the ConstraintCollection
  55                                 //handle exceptions when this value changes
  56                                 _onConstraintNameChange(value);
  57                                 _constraintName = value;
  58                         }
  59                 }
  60
  61                 public PropertyCollection ExtendedProperties {
  62                         get {
  63                                 return _properties;
  64                         }
  65                 }
  66
  67                 public abstract DataTable Table {
  68                         get;
  69                 }
  70
  71                 /// <summary>
  72                 /// Gets the ConstraintName, if there is one, as a string.
  73                 /// </summary>
  74                 public override string ToString()
  75                 {
  76                         return "" + _constraintName;
  77                 }
  78
  79                 internal ConstraintCollection ConstraintCollection {
  80                         get{
  81                                 return _constraintCollection;
  82                         }
  83                         set{
  84                                 _constraintCollection = value;
  85                         }
  86                 }
  87
  88
  89                 private void _onConstraintNameChange(string newName)
  90                 {
  91                         if (null != BeforeConstraintNameChange)
  92                         {
  93                                 BeforeConstraintNameChange(this, newName);
  94                         }
  95                 }
  96
  97                 //call once before adding a constraint to a collection
  98                 //will throw an exception to prevent the add if a rule is broken
  99                 internal virtual void AddToConstraintCollectionSetup(
 100                         ConstraintCollection collection){}
 101
 102                 //call once before removing a constraint to a collection
 103                 //can throw an exception to prevent the removal
 104                 internal virtual void RemoveFromConstraintCollectionCleanup(
 105                         ConstraintCollection collection){}
 106
 107                 internal virtual void AssertConstraint(){}
 108
 109                 internal virtual void AssertConstraint(DataRow row){}
 110         }
 111 }