Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Web.Extensions/ui/WebControls/Expressions/DataSourceExpression.cs

@@ -0,0 +1,125 @@
+namespace System.Web.UI.WebControls.Expressions {
+    using System;
+    using System.ComponentModel;
+    using System.Linq;
+    using System.Linq.Expressions;
+    using System.Web;
+    using System.Web.UI;
+    using System.Web.UI.WebControls;
+    
+  
+    public abstract class DataSourceExpression : IStateManager {
+        private bool _tracking;
+        private StateBag _viewState;
+
+        protected HttpContext Context {
+            get;
+            private set;
+        }
+
+        protected Control Owner {
+            get;
+            private set;
+        }     
+
+        public IQueryableDataSource DataSource {
+            get;
+            // Internal set for unit testing
+            internal set;
+        }
+
+
+        protected bool IsTrackingViewState {
+            get {
+                return _tracking;
+            }
+        }        
+
+        [
+        Browsable(false),
+        DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden),
+        ]
+        protected StateBag ViewState {
+            get {
+                if (_viewState == null) {
+                    _viewState = new StateBag();
+                    if (_tracking)
+                        ((IStateManager)_viewState).TrackViewState();
+                }
+                return _viewState;
+            }
+        }
+
+        protected DataSourceExpression() {
+        }
+
+        // internal for unit testing
+        internal DataSourceExpression(Control owner) {
+            Owner = owner;
+        }
+
+        public void SetDirty() {
+            ViewState.SetDirty(true);
+        }
+
+        protected virtual void LoadViewState(object savedState) {
+            if (savedState != null) {
+                ((IStateManager)ViewState).LoadViewState(savedState);
+            }
+        }
+
+        protected virtual object SaveViewState() {
+            return (_viewState != null) ? ((IStateManager)_viewState).SaveViewState() : null;
+        }
+
+        protected virtual void TrackViewState() {
+            _tracking = true;
+
+            if (_viewState != null) {
+                ((IStateManager)_viewState).TrackViewState();
+            }
+        }
+
+        public abstract IQueryable GetQueryable(IQueryable source);
+
+        public virtual void SetContext(Control owner, HttpContext context, IQueryableDataSource dataSource) {
+            if (owner == null) {
+                throw new ArgumentNullException("owner");
+            }
+
+            if (context == null) {
+                throw new ArgumentNullException("context");
+            }
+
+            if (dataSource == null) {
+                throw new ArgumentNullException("dataSource");
+            }
+
+            Owner = owner;
+            Context = context;
+            DataSource = dataSource;
+        }
+
+        #region IStateManager Members
+
+        bool IStateManager.IsTrackingViewState {
+            get {
+                return IsTrackingViewState;
+            }
+        }
+
+        void IStateManager.LoadViewState(object state) {
+            LoadViewState(state);
+        }
+
+        object IStateManager.SaveViewState() {
+            return SaveViewState();
+        }
+
+        void IStateManager.TrackViewState() {
+            TrackViewState();
+        }
+
+        #endregion
+    }
+}