Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Web.DynamicData/DynamicData/ModelProviders/AssociationProvider.cs

@@ -0,0 +1,125 @@
+using System.Collections.ObjectModel;
+using System.Globalization;
+using System.Web.Resources;
+
+namespace System.Web.DynamicData.ModelProviders {
+    /// <summary>
+    /// Specifies the association cardinality
+    /// </summary>
+    public enum AssociationDirection {
+        /// <summary>
+        /// 1-1
+        /// </summary>
+        OneToOne,
+        /// <summary>
+        /// one to many
+        /// </summary>
+        OneToMany,
+        /// <summary>
+        /// many to one
+        /// </summary>
+        ManyToOne,
+        /// <summary>
+        /// many to many
+        /// </summary>
+        ManyToMany
+    }
+
+    /// <summary>
+    /// Base provider class for associations between columns
+    /// Each provider type (e.g. Linq To Sql, Entity Framework, 3rd party) extends this class.
+    /// </summary>
+    public abstract class AssociationProvider {
+        private TableProvider _toTable;
+
+        /// <summary>
+        /// The type of association
+        /// </summary>
+        public virtual AssociationDirection Direction { get; protected set; }
+
+        /// <summary>
+        /// The source column of the association
+        /// </summary>
+        public virtual ColumnProvider FromColumn { get; protected set; }
+
+        /// <summary>
+        /// The destination table of the association
+        /// </summary>
+        public virtual TableProvider ToTable {
+            get {
+                if (_toTable != null) {
+                    return _toTable;
+                }
+
+                if (ToColumn != null) {
+                    return ToColumn.Table;
+                }
+
+                return null;
+            }
+            protected set {
+                _toTable = value;
+            }
+        }
+
+        /// <summary>
+        /// The destination column of the association
+        /// </summary>
+        public virtual ColumnProvider ToColumn { get; protected set; }
+
+        /// <summary>
+        /// Returns true if the From Column part of the primary key of its table
+        /// e.g. Order and Product are PKs in the Order_Details table
+        /// </summary>
+        public virtual bool IsPrimaryKeyInThisTable { get; protected set; }
+
+        /// <summary>
+        /// The names of the underlying foreign keys that make up this association
+        /// </summary>
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly", Justification="It's a readonly collection, so the warning is incorrect")]
+        public virtual ReadOnlyCollection<string> ForeignKeyNames { get; protected set; }
+
+        /// <summary>
+        /// Returns a string representing the sort expression that would be used for
+        /// sorting the column represented by this association. The parameter is the
+        /// property of the strongly typed entity used as the sort key for that entity.
+        /// For example, assume that this association represents the Category column
+        /// in the Products table. The sortColumn paramater is "CategoryName",
+        /// meaning that this method is being asked to return the sort expression for
+        /// sorting the Category column by the CategoryName property of the Category entity.
+        /// The result sort expression would be "Category.CategoryName".
+        /// The result of this method should be affected by whether the underlying data
+        /// model is capable of sorting the entity by the given sort column (see
+        /// ColumnProvider.IsSortable). The method can return a null value to indicate
+        /// that sorting is not supported.
+        /// </summary>
+        /// <param name="sortColumn">the column to sort the entity by</param>
+        /// <returns>the sort expression string, or null if sort is not supported for the
+        /// given sort column</returns>
+        public virtual string GetSortExpression(ColumnProvider sortColumn) {
+            return null;
+        }
+
+        internal string GetSortExpression(ColumnProvider sortColumn, string format) {
+            if (Direction == AssociationDirection.OneToMany || Direction == AssociationDirection.ManyToMany) {
+                throw new InvalidOperationException(String.Format(CultureInfo.CurrentCulture,
+                    DynamicDataResources.AssociationProvider_DirectionDoesNotSupportSorting,
+                    Direction));
+            }
+
+            if (sortColumn == null) {
+                throw new ArgumentNullException("sortColumn");
+            }
+
+            if (!ToTable.Columns.Contains(sortColumn)) {
+                throw new ArgumentException(DynamicDataResources.AssociationProvider_SortColumnDoesNotBelongToEndTable, "sortColumn");
+            }
+
+            if (sortColumn.IsSortable) {
+                return String.Format(CultureInfo.InvariantCulture, format, FromColumn.Name, sortColumn.Name);
+            } else {
+                return null;
+            }
+        }
+    }
+}