class/System.Web.Mvc/System.Web.Mvc/ViewUserControl.cs

   1 /* ****************************************************************************
   2  *
   3  * Copyright (c) Microsoft Corporation. All rights reserved.
   4  *
   5  * This software is subject to the Microsoft Public License (Ms-PL).
   6  * A copy of the license can be found in the license.htm file included
   7  * in this distribution.
   8  *
   9  * You must not remove this notice, or any other, from this software.
  10  *
  11  * ***************************************************************************/
  12
  13 namespace System.Web.Mvc {
  14     using System;
  15     using System.ComponentModel;
  16     using System.Diagnostics.CodeAnalysis;
  17     using System.Globalization;
  18     using System.Web.Mvc.Resources;
  19     using System.Web.UI;
  20
  21     [FileLevelControlBuilder(typeof(ViewUserControlControlBuilder))]
  22     public class ViewUserControl : UserControl, IViewDataContainer {
  23         private AjaxHelper _ajaxHelper;
  24         private HtmlHelper _htmlHelper;
  25         private ViewContext _viewContext;
  26         private ViewDataDictionary _viewData;
  27         private string _viewDataKey;
  28
  29         public AjaxHelper Ajax {
  30             get {
  31                 if (_ajaxHelper == null) {
  32                     _ajaxHelper = new AjaxHelper(ViewContext, this);
  33                 }
  34                 return _ajaxHelper;
  35             }
  36         }
  37
  38         public HtmlHelper Html {
  39             get {
  40                 if (_htmlHelper == null) {
  41                     _htmlHelper = new HtmlHelper(ViewContext, this);
  42                 }
  43                 return _htmlHelper;
  44             }
  45         }
  46
  47         public object Model {
  48             get {
  49                 return ViewData.Model;
  50             }
  51         }
  52
  53         public TempDataDictionary TempData {
  54             get {
  55                 return ViewPage.TempData;
  56             }
  57         }
  58
  59         public UrlHelper Url {
  60             get {
  61                 return ViewPage.Url;
  62             }
  63         }
  64
  65         [Browsable(false)]
  66         [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
  67         public ViewContext ViewContext {
  68             get {
  69                 return _viewContext ?? ViewPage.ViewContext;
  70             }
  71             set {
  72                 _viewContext = value;
  73             }
  74         }
  75
  76         [SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly",
  77             Justification = "This is the mechanism by which the ViewUserControl gets its ViewDataDictionary object.")]
  78         [Browsable(false)]
  79         [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
  80         public ViewDataDictionary ViewData {
  81             get {
  82                 EnsureViewData();
  83                 return _viewData;
  84             }
  85             set {
  86                 SetViewData(value);
  87             }
  88         }
  89
  90         [DefaultValue("")]
  91         public string ViewDataKey {
  92             get {
  93                 return _viewDataKey ?? String.Empty;
  94             }
  95             set {
  96                 _viewDataKey = value;
  97             }
  98         }
  99
 100         internal ViewPage ViewPage {
 101             get {
 102                 ViewPage viewPage = Page as ViewPage;
 103                 if (viewPage == null) {
 104                     throw new InvalidOperationException(MvcResources.ViewUserControl_RequiresViewPage);
 105                 }
 106                 return viewPage;
 107             }
 108         }
 109
 110         public HtmlTextWriter Writer {
 111             get {
 112                 return ViewPage.Writer;
 113             }
 114         }
 115
 116         protected virtual void SetViewData(ViewDataDictionary viewData) {
 117             _viewData = viewData;
 118         }
 119
 120         protected void EnsureViewData() {
 121             if (_viewData != null) {
 122                 return;
 123             }
 124
 125             // Get the ViewData for this ViewUserControl, optionally using the specified ViewDataKey
 126             IViewDataContainer vdc = GetViewDataContainer(this);
 127             if (vdc == null) {
 128                 throw new InvalidOperationException(
 129                     String.Format(
 130                         CultureInfo.CurrentUICulture,
 131                         MvcResources.ViewUserControl_RequiresViewDataProvider,
 132                         AppRelativeVirtualPath));
 133             }
 134
 135             ViewDataDictionary myViewData = vdc.ViewData;
 136
 137             // If we have a ViewDataKey, try to extract the ViewData from the dictionary, otherwise
 138             // return the container's ViewData.
 139             if (!String.IsNullOrEmpty(ViewDataKey)) {
 140                 object target = myViewData.Eval(ViewDataKey);
 141                 myViewData = target as ViewDataDictionary ?? new ViewDataDictionary(myViewData) { Model = target };
 142             }
 143
 144             SetViewData(myViewData);
 145         }
 146
 147         private static IViewDataContainer GetViewDataContainer(Control control) {
 148             // Walk up the control hierarchy until we find someone that implements IViewDataContainer
 149             while (control != null) {
 150                 control = control.Parent;
 151                 IViewDataContainer vdc = control as IViewDataContainer;
 152                 if (vdc != null) {
 153                     return vdc;
 154                 }
 155             }
 156             return null;
 157         }
 158
 159         public virtual void RenderView(ViewContext viewContext) {
 160             // TODO: Remove this hack. Without it, the browser appears to always load cached output
 161             viewContext.HttpContext.Response.Cache.SetExpires(DateTime.Now);
 162             ViewUserControlContainerPage containerPage = new ViewUserControlContainerPage(this);
 163             // Tracing requires Page IDs to be unique.
 164             ID = Guid.NewGuid().ToString();
 165
 166             RenderViewAndRestoreContentType(containerPage, viewContext);
 167         }
 168
 169         internal static void RenderViewAndRestoreContentType(ViewPage containerPage, ViewContext viewContext) {
 170             // We need to restore the Content-Type since Page.SetIntrinsics() will reset it. It's not possible
 171             // to work around the call to SetIntrinsics() since the control's render method requires the
 172             // containing page's Response property to be non-null, and SetIntrinsics() is the only way to set
 173             // this.
 174             string savedContentType = viewContext.HttpContext.Response.ContentType;
 175             containerPage.RenderView(viewContext);
 176             viewContext.HttpContext.Response.ContentType = savedContentType;
 177         }
 178
 179         private sealed class ViewUserControlContainerPage : ViewPage {
 180             public ViewUserControlContainerPage(ViewUserControl userControl) {
 181                 Controls.Add(userControl);
 182             }
 183         }
 184     }
 185 }