scriptcontrolbase.cs

AJAX 应用 实现页面的无刷新

            if (control != null)
            {
                return control;
            }
            for (Control container = NamingContainer; container != null; container = container.NamingContainer)
            {
                control = container.FindControl(id);
                if (control != null)
                {
                    return control;
                }
            }
            // NOTE: [rb] I'm not implementing ResolveControlID just yet. I prefer to use a colon (:) seperated ID name to get to controls inside of a naming container
            // e.g. TargetControlID="LoginView1:LoginButton" works just as well
            return null;
        }

        /// <summary>
        /// Handles OnLoad
        /// </summary>
        /// <param name="e">event args</param>
        protected override void OnLoad(EventArgs e)
        {
            base.OnLoad(e);

            ScriptObjectBuilder.RegisterCssReferences(this);
        }

        /// <summary>
        /// Fires the PreRender event
        /// </summary>
        /// <param name="e"></param>
        protected override void OnPreRender(EventArgs e)
        {
            base.OnPreRender(e);

            EnsureID();

            EnsureScriptManager();

            if (SupportsClientState)
            {
                ScriptManager.RegisterHiddenField(this, ClientStateFieldID, SaveClientState());

                Page.RegisterRequiresPostBack(this);
            }
        }

        /// <summary>
        /// Loads the client state data
        /// </summary>
        /// <param name="clientState"></param>
        protected virtual void LoadClientState(string clientState)
        {
        }

        /// <summary>
        /// Saves the client state data
        /// </summary>
        /// <returns></returns>
        protected virtual string SaveClientState()
        {
            return null;
        }

        /// <summary>
        /// Executed when post data is loaded from the request
        /// </summary>
        /// <param name="postDataKey"></param>
        /// <param name="postCollection"></param>
        /// <returns></returns>
        protected virtual bool LoadPostData(string postDataKey, NameValueCollection postCollection)
        {
            if (SupportsClientState)
            {
                string clientState = postCollection[ClientStateFieldID];
                if (!string.IsNullOrEmpty(clientState))
                {
                    LoadClientState(clientState);
                }
            }
            return false;
        }

        /// <summary>
        /// Executed when post data changes should invoke a chagned event
        /// </summary>
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1030:UseEventsWhereAppropriate", Justification = "Maintaining consistency with IPostBackDataHandler")]
        protected virtual void RaisePostDataChangedEvent()
        {
        }

        /// <summary>
        /// Gets the ScriptDescriptors that make up this control
        /// </summary>
        /// <returns></returns>
        protected override IEnumerable<ScriptDescriptor> GetScriptDescriptors()
        {
            if (!Visible) return null;

            EnsureID();

            // store descriptors for this object
            List<ScriptDescriptor> descriptors = new List<ScriptDescriptor>();

            // build the default description
            ScriptControlDescriptor descriptor = new ScriptControlDescriptor(ClientControlType, ClientID);
            DescribeComponent(descriptor);
            descriptors.Add(descriptor);

            // return the description
            return descriptors;
        }

        /// <summary>
        /// Gets the script references for this control
        /// </summary>
        /// <returns></returns>
        protected override IEnumerable<ScriptReference> GetScriptReferences()
        {
            if (!Visible) return null;

            List<ScriptReference> refs = new List<ScriptReference>();
            refs.AddRange(ScriptObjectBuilder.GetScriptReferences(GetType()));
            if (ScriptPath.Length > 0)
            {
                refs.Add(new ScriptReference(ScriptPath));
            }
            return refs;
        }

        /// <summary>
        /// Describes the settings for this control.
        /// </summary>
        /// <param name="descriptor"></param>
        protected virtual void DescribeComponent(ScriptComponentDescriptor descriptor)
        {
            try
            {
                _renderingScript = true;
                ScriptObjectBuilder.DescribeComponent(this, descriptor, this, this);
            }
            finally
            {
                _renderingScript = false;
            }
            if (SupportsClientState)
            {
                descriptor.AddElementProperty("clientStateField", ClientStateFieldID);
            }
        }

        /// <summary>
        /// Handles a callback event
        /// </summary>
        /// <returns></returns>
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1024:UsePropertiesWhereAppropriate", Justification = "Method has a side-effect")]
        protected virtual string GetCallbackResult()
        {
            string argument = _callbackArgument;
            _callbackArgument = null;
            return ScriptObjectBuilder.ExecuteCallbackMethod(this, argument);
        }

        /// <summary>
        /// Raises a callback event
        /// </summary>
        /// <param name="eventArgument"></param>
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1030:UseEventsWhereAppropriate", Justification = "Maintaining consistency with ICallbackEventHandler")]
        protected virtual void RaiseCallbackEvent(string eventArgument)
        {
            _callbackArgument = eventArgument;
        }

        #endregion

        #region [ IControlResolver Members ]

        public Control ResolveControl(string controlId)
        {
            return FindControl(controlId);
        }

        #endregion

        #region [ IPostBackDataHandler Members ]

        bool IPostBackDataHandler.LoadPostData(string postDataKey, NameValueCollection postCollection)
        {
            return LoadPostData(postDataKey, postCollection);
        }

        void IPostBackDataHandler.RaisePostDataChangedEvent()
        {
            RaisePostDataChangedEvent();
        }

        #endregion

        #region [ ICallbackEventHandler Members ]

        string ICallbackEventHandler.GetCallbackResult()
        {
            return GetCallbackResult();
        }

        void ICallbackEventHandler.RaiseCallbackEvent(string eventArgument)
        {
            RaiseCallbackEvent(eventArgument);
        }

        #endregion

        #region [ IClientStateManager Members ]

        bool IClientStateManager.SupportsClientState
        {
            get { return SupportsClientState; }
        }

        void IClientStateManager.LoadClientState(string clientState)
        {
            LoadClientState(clientState);
        }

        string IClientStateManager.SaveClientState()
        {
            return SaveClientState();
        }

        #endregion
    }
}