ChtmlPageAdapter.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / MIT / System / Web / UI / MobileControls / Adapters / ChtmlPageAdapter.cs / 1305376 / ChtmlPageAdapter.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

using System.Collections.Specialized; 
using System.Globalization; 
using System.IO;
using System.Web.Mobile; 
using System.Web.UI.MobileControls.Adapters;
using System.Security.Permissions;

#if COMPILING_FOR_SHIPPED_SOURCE 
namespace System.Web.UI.MobileControls.ShippedAdapterSource
#else 
namespace System.Web.UI.MobileControls.Adapters 
#endif
 
{

    /*
     * ChtmlPageAdapter class. 
     *
     * Copyright (c) 2000 Microsoft Corporation 
     */ 
    /// 
    [AspNetHostingPermission(SecurityAction.LinkDemand, Level=AspNetHostingPermissionLevel.Minimal)] 
    [AspNetHostingPermission(SecurityAction.InheritanceDemand, Level=AspNetHostingPermissionLevel.Minimal)]
    [Obsolete("The System.Web.Mobile.dll assembly has been deprecated and should no longer be used. For information about how to develop ASP.NET mobile applications, see http://go.microsoft.com/fwlink/?LinkId=157231.")]
    public class ChtmlPageAdapter : HtmlPageAdapter
    { 
        private const int DefaultPageWeight = 800;
        private const String _postedFromOtherFile = "."; 
 
        /// 
        public ChtmlPageAdapter() : base(DefaultPageWeight) 
        {
        }

        ///////////////////////////////////////////////////////////////////// 
        //  Static method used for determining if device should use
        //  this adapter 
        ///////////////////////////////////////////////////////////////////// 

        ///  
        public new static bool DeviceQualifies(HttpContext context)
        {
            String type = ((MobileCapabilities)context.Request.Browser).PreferredRenderingType;
            bool javascriptSupported = context.Request.Browser.JavaScript; 
            bool qualifies = (type == MobileCapabilities.PreferredRenderingTypeHtml32 ||
                              type == MobileCapabilities.PreferredRenderingTypeChtml10) 
                             && !javascriptSupported; 
            return qualifies;
        } 

        /////////////////////////////////////////////////////////////////////
        //  IControlAdapter implementation
        ///////////////////////////////////////////////////////////////////// 

        ///  
        public override void RenderPostBackEvent(HtmlMobileTextWriter writer, 
                                                String target,
                                                String argument) 
        {
            // Since it doesn't have scripts, the CHTML adapter
            // only supports URL postback events.
 
            RenderUrlPostBackEvent(writer, target, argument);
        } 
 
        /// 
        protected override String EventSourceKey 
        {
            get
            {
                return Constants.EventSourceID; 
            }
        } 
 
        /// 
        protected override String EventArgumentKey 
        {
            get
            {
                return Constants.EventArgumentID; 
            }
        } 
 
        /// 
        public override void RenderPostBackHeader(HtmlMobileTextWriter writer, Form form) 
        {
            bool postBack = form.Action.Length == 0;

            RenderPageState(writer); 
            if (!postBack)
            { 
                writer.WriteHiddenField(EventSourceKey, _postedFromOtherFile); 
            }
            else if (Page.ClientViewState == null) 
            {
                // The empty event source variable is used to identify a
                // postback request
                writer.WriteHiddenField(EventSourceKey, String.Empty); 
            }
 
            RenderHiddenVariables(writer); 
        }
 
        /////////////////////////////////////////////////////////////////////
        //  IPageAdapter implementation
        /////////////////////////////////////////////////////////////////////
 
        // =================================================================
        // For browser that doesn't support javascript, like cHTML browser, 
        // control id and its corresponding value are specially encoded in 
        // the post back data collection.  This method is to extract the
        // encoded info and put the info back to the collection in an 
        // expected format that is understood by ASP.NET Frameworks so post
        // back event is raised correctly.
        // Note other control adapters should do the encoding accordinly so
        // the data can be decoded properly here. 
        //
        ///  
        public override NameValueCollection DeterminePostBackMode 
        (
            HttpRequest request, 
            String postEventSourceID,
            String postEventArgumentID,
            NameValueCollection baseCollection
        ) 
        {
            if (baseCollection != null && baseCollection[EventSourceKey] == _postedFromOtherFile) 
            { 
                return null;
            } 
            else if (request == null)
            {
                return baseCollection;
            } 
            else if (String.Compare(request.HttpMethod, "POST", StringComparison.OrdinalIgnoreCase) == 0)
            { 
                return CollectionFromForm(request.Form, 
                                          postEventSourceID,
                                          postEventArgumentID); 
            }
            else if (request.QueryString.Count == 0)
            {
                return baseCollection; 
            }
            else 
            { 
                return CollectionFromQueryString(request.QueryString,
                                                 postEventSourceID, 
                                                 postEventArgumentID);
            }
        }
 
        /// 
        public override HtmlTextWriter CreateTextWriter(TextWriter writer) 
        { 
            return new ChtmlMobileTextWriter(writer, Device);
        } 

        private NameValueCollection CollectionFromQueryString(
            NameValueCollection queryString,
            String postEventSourceID, 
            String postEventArgumentID)
        { 
            NameValueCollection collection = new NameValueCollection(); 
            bool isPostBack = false;
 
            for (int i = 0; i < queryString.Count; i++)
            {
                String name = queryString.GetKey(i);
 
                // Supposingly, we should double check if the control id
                // is real or not by checking against the control tree. 
                // However, the tree can't be checked because it hasn't 
                // been built at this stage.  And this is the only place
                // we can override the value collection.  We just need to 
                // assume the control adapters are setting the id and
                // value accordingly.

                // ASSUMPTION: In query string, besides the expected 
                // name/value pairs (ViewStateID, EventSource and
                // EventArgument), there are hidden variables, control 
                // id/value pairs (if the form submit method is GET), unique 
                // file path suffix variable and custom query string text.
                // They will be in the above order if any of them present. 
                // Hidden variables and control id/value pairs should be added
                // back to the collection intactly, but the other 2 items
                // should not be added to the collection.
 
                // name can be null if there is a query name without equal
                // sign appended.  We should just ignored it in this case. 
                if (name == null) 
                {
                    continue; 
                }
                else if (name == MobilePage.ViewStateID)
                {
                    collection.Add(MobilePage.ViewStateID, queryString.Get(i)); 
                    isPostBack = true;
                } 
                else if (name == Constants.EventSourceID) 
                {
                    collection.Add(postEventSourceID, queryString.Get(i)); 
                    isPostBack = true;
                }
                else if (name == Constants.EventArgumentID)
                { 
                    collection.Add(postEventArgumentID, queryString.Get(i));
                } 
                else if (Constants.UniqueFilePathSuffixVariable.StartsWith(name, StringComparison.Ordinal)) 
                {
                    // At this point we know that the rest of them is 
                    // the custom query string text, so we are done.
                    break;
                }
                else 
                {
                    AddValues(queryString, name, collection); 
                } 
            }
 
            if (collection.Count == 0 || !isPostBack)
            {
                // Returning null to indicate this is not a postback
                return null; 
            }
            else 
            { 
                return collection;
            } 
        }

        // =================================================================
        // The complexity (multiple if statements) of this method is due to 
        // workarounds for different targeted devices and limitation on non-
        // javascript html browser. 
        // 
        private NameValueCollection CollectionFromForm(
            NameValueCollection form, 
            String postEventSourceID,
            String postEventArgumentID)
        {
            int i; 
            int count = form.Count;
            NameValueCollection collection = new NameValueCollection(); 
            bool isPostBack = false; 

            // continue statements are used below to simplify the logic and 
            // make people easier to follow and maintain the code.
            for (i = 0; i < count; i++)
            {
                String name = form.GetKey(i); 

                // 1. Some browser returns the name of a password textbox 
                // only without the expected character "=" if the textbox is 
                // empty.  This causes the key to be null and the name to be
                // the value of the collection item when the returned form 
                // content is parsed in HttpValueCollection.  In this case,
                // we need to reverse the setting with the value as the name
                // and empty string as the value so subsequent manipulations
                // of the collection work correctly. 
                if (name == null)
                { 
                    if (AddEmptyStringValues(form.GetValues(i), collection)) { 
                        isPostBack = true;
                    } 
                    continue;
                }

                // 2. Pager navigation is rendered by buttons which have the 
                // targeted page number appended to the form id after
                // PagePrefix which is a constant string to identify this 
                // special case.  E.g. ControlID__PG_2 
                int index = name.LastIndexOf(Constants.PagePrefix, StringComparison.Ordinal);
                if (index != -1) 
                {
                    // We need to associate the form id with the event source
                    // id and the page number with the event argument id in
                    // order to have the event raised properly by ASP.NET 
                    int pageBeginPos = index + Constants.PagePrefix.Length;
                    collection.Add(postEventSourceID, 
                                   name.Substring(0, index)); 
                    collection.Add(postEventArgumentID,
                                   name.Substring(pageBeginPos, 
                                              name.Length - pageBeginPos));
                    continue;
                }
 
                // 3. This special case happens when A. SelectionList control is
                // with property SelectType equal to CheckBox or 
                // MultiSelectListBox, and the device itself doesn't handle 
                // multiple check boxes correctly. or B. Browser requires the
                // ID of the input element to be unique during postbacks. 
                //
                // In this case, the control (SelectionList or TextBox) adapter
                // appended special characters as a suffix of the actual control
                // id. That should be stripped off when detected. 
                if (Device.RequiresUniqueHtmlCheckboxNames ||
                    Device.RequiresUniqueHtmlInputNames) 
                { 
                    index = name.LastIndexOf(
                        Constants.SelectionListSpecialCharacter); 

                    if (index != -1)
                    {
                        String value = form.Get(i); 
                        if (!String.IsNullOrEmpty(value))
                        { 
                            if(Device.RequiresAttributeColonSubstitution) 
                            {
                                collection.Add(name.Substring(0, index).Replace(',',':'), value); 
                            }
                            else
                            {
                                collection.Add(name.Substring(0, index), value); 
                            }
                            continue; 
                        } 
                    }
                } 

                // 4. This is to determine if the request is a postback from
                // the same mobile page.
                if (name == MobilePage.ViewStateID || 
                    name == EventSourceKey)
                { 
                    isPostBack = true; 
                }
 
                // Default case, just preserve the value(s)
                AddValues(form, name, collection);
            }
 
            if (collection.Count == 0 || !isPostBack)
            { 
                // Returning null to indicate this is not a postback 
                return null;
            } 
            else
            {
                return collection;
            } 
        }
 
        // Helper function to add empty string as value for the keys 
        private bool AddEmptyStringValues(String [] keys,
                                        NameValueCollection targetCollection) 
        {
            bool result = false;
            foreach (String key in keys)
            { 
                if (key == MobilePage.ViewStateID ||
                    key == EventSourceKey) { 
                    result = true; 
                }
                targetCollection.Add(key, String.Empty); 
            }
            return result;
        }
 
        // Helper function to add multiple values for the same key
        private void AddValues(NameValueCollection sourceCollection, 
                               String sourceKey, 
                               NameValueCollection targetCollection)
        { 
            String [] values = sourceCollection.GetValues(sourceKey);
            foreach (String value in values)
            {
                if(Device.RequiresAttributeColonSubstitution) 
                {
                    targetCollection.Add(sourceKey.Replace(',',':'), value); 
                } 
                else
                { 
                    targetCollection.Add(sourceKey, value);
                }
            }
        } 
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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ChtmlPageAdapter.cs source code in C# .NET

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