Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Web.DynamicData/DynamicData/DynamicRouteExpression.cs

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+using System.Collections;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Linq;
+using System.Web.DynamicData.Util;
+using System.Web.UI;
+using System.Web.UI.WebControls;
+using System.Diagnostics;
+using System.Web.UI.WebControls.Expressions;
+
+namespace System.Web.DynamicData {
+    /// <summary>
+    /// This class is an QueryExtender-based equivalent of DynamicQueryStringParameters.
+    /// When applied to a data source it will filter the data by the value of a primary key encoded
+    /// in the requests query string (or potentially routing if complex routes are used). If ColumnName
+    /// is specified it will retrieve the values
+    /// </summary>
+    public class DynamicRouteExpression : DataSourceExpression {
+        private PropertyExpression _expression = new PropertyExpression();
+
+        /// <summary>
+        /// An optional column name that can be used to change the filtering mode (i.e. filter by foreign key instead
+        /// of primary key).
+        /// </summary>
+        [DefaultValue("")]
+        public string ColumnName { get; set; }
+
+        /// <summary>
+        /// See base class.
+        /// </summary>
+        public override void SetContext(Control owner, HttpContext context, IQueryableDataSource dataSource) {
+            base.SetContext(owner, context, dataSource);
+
+            owner.Page.InitComplete += new EventHandler(Page_InitComplete);
+        }
+
+        void Page_InitComplete(object sender, EventArgs e) {
+            Debug.Assert(DataSource != null);
+            var table = DataSource.GetMetaTable();
+
+            IEnumerable<Parameter> parameters = RouteParametersHelper.GetColumnParameters(table, ColumnName);
+            parameters.ToList().ForEach(p => _expression.Parameters.Add(p));
+        }
+
+        /// <summary>
+        /// See base class.
+        /// </summary>
+        public override IQueryable GetQueryable(IQueryable source) {
+            return _expression.GetQueryable(source);
+        }
+    }
+}