Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Web/UI/WebControls/CompositeDataBoundControl.cs

@@ -0,0 +1,159 @@
+//------------------------------------------------------------------------------
+// <copyright file="CompositeDataBoundControl.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//------------------------------------------------------------------------------
+
+namespace System.Web.UI.WebControls {
+
+    using System;
+    using System.Collections;
+    using System.ComponentModel;
+
+    public abstract class CompositeDataBoundControl : DataBoundControl, INamingContainer {
+
+        internal const string ItemCountViewStateKey = "_!ItemCount";
+
+        private string _updateMethod;
+        private string _insertMethod;
+        private string _deleteMethod;
+
+        protected override bool IsUsingModelBinders {
+            get {
+                return !String.IsNullOrEmpty(SelectMethod) ||
+                       !String.IsNullOrEmpty(UpdateMethod) ||
+                       !String.IsNullOrEmpty(DeleteMethod) ||
+                       !String.IsNullOrEmpty(InsertMethod);
+            }
+        }
+
+        /// <summary>
+        /// The name of the method on the page which is called when this Control does an update operation.
+        /// </summary>
+        protected internal string UpdateMethod {
+            get {
+                return _updateMethod ?? String.Empty;
+            }
+            set {
+                if (!String.Equals(_updateMethod, value, StringComparison.OrdinalIgnoreCase)) {
+                    _updateMethod = value;
+                    OnDataPropertyChanged();
+                }
+            }
+        }
+
+        /// <summary>
+        /// The name of the method on the page which is called when this Control does a delete operation.
+        /// </summary>
+        protected internal string DeleteMethod {
+            get {
+                return _deleteMethod ?? String.Empty;
+            }
+            set {
+                if (!String.Equals(_deleteMethod, value, StringComparison.OrdinalIgnoreCase)) {
+                    _deleteMethod = value;
+                    OnDataPropertyChanged();
+                }
+            }
+        }
+
+        /// <summary>
+        /// The name of the method on the page which is called when this Control does an insert operation.
+        /// </summary>
+        protected internal string InsertMethod {
+            get {
+                return _insertMethod ?? String.Empty;
+            }
+            set {
+                if (!String.Equals(_insertMethod, value, StringComparison.OrdinalIgnoreCase)) {
+                    _insertMethod = value;
+                    OnDataPropertyChanged();
+                }
+            }
+        }
+
+        public override ControlCollection Controls {
+            get {
+                EnsureChildControls();
+                return base.Controls;
+            }
+        }
+
+        /// <summary>
+        /// Overriden by DataBoundControl to determine if the control should
+        /// recreate its control hierarchy based on values in view state.
+        /// If the control hierarchy should be created, i.e. view state does
+        /// exist, it calls CreateChildControls with a dummy (empty) data source
+        /// which is usable for enumeration purposes only.
+        /// </summary>
+        protected internal override void CreateChildControls() {
+            Controls.Clear();
+            object controlCount = ViewState[ItemCountViewStateKey];
+
+            if (controlCount == null && RequiresDataBinding) {
+                EnsureDataBound();
+            }
+
+            if (controlCount != null && ((int)controlCount) != -1) {
+                DummyDataSource dummyDataSource = new DummyDataSource((int)controlCount);
+                CreateChildControls(dummyDataSource, false);
+                ClearChildViewState();
+            }
+        }
+
+
+        /// <summary>
+        /// Performs the work of creating the control hierarchy based on a data source.
+        /// When dataBinding is true, the specified data source contains real
+        /// data, and the data is supposed to be pushed into the UI.
+        /// When dataBinding is false, the specified data source is a dummy data
+        /// source, that allows enumerating the right number of items, but the items
+        /// themselves are null and do not contain data. In this case, the recreated
+        /// control hierarchy reinitializes its state from view state.
+        /// It enables a DataBoundControl to encapsulate the logic of creating its
+        /// control hierarchy in both modes into a single code path.
+        /// </summary>
+        /// <param name="dataSource">
+        /// The data source to be used to enumerate items.
+        /// </param>
+        /// <param name="dataBinding">
+        /// Whether the method has been called from DataBind or not.
+        /// </param>
+        /// <returns>
+        /// The number of items created based on the data source. Put another way, its
+        /// the number of items enumerated from the data source.
+        /// </returns>
+        protected abstract int CreateChildControls(IEnumerable dataSource,
+                                                   bool dataBinding);
+
+
+        /// <summary>
+        /// Overriden by DataBoundControl to use its properties to determine the real
+        /// data source that the control should bind to. It then clears the existing
+        /// control hierarchy, and calls createChildControls to create a new control
+        /// hierarchy based on the resolved data source.
+        /// The implementation resolves various data source related properties to
+        /// arrive at the appropriate IEnumerable implementation to use as the real
+        /// data source.
+        /// When resolving data sources, the DataSourceControlID takes highest precedence.
+        /// In this mode, DataMember is used to access the appropriate list from the
+        /// DataControl.
+        /// If DataSourceControlID is not set, the value of the DataSource property is used.
+        /// In this second alternative, DataMember is used to extract the appropriate
+        /// list if the control has been handed an IListSource as a data source.
+        /// </summary>
+        protected internal override void PerformDataBinding(IEnumerable data) {
+            base.PerformDataBinding(data);
+
+            Controls.Clear();
+            ClearChildViewState();
+
+            TrackViewState();
+
+            int controlCount = CreateChildControls(data, true);
+            ChildControlsCreated = true;
+            ViewState[ItemCountViewStateKey] = controlCount;
+        }
+    }
+}
+