Postback Manager

In questo esempio illustriamo un possibile utilizzo del PostbackManager: un utility control che provvede in maniera semplice ad eseguire richieste asincrone e gestire le richieste fatte dai controlli web ADF. Le richieste asincrone possono essere preparate tramite il metodo doAsyncRequest del PostbackManager e processate nel web tier mediante l'evento RequestReceived. Le richieste fatte tramite i controlli web ADF possono essere gestite prima di essere inviate al server con l'evento invokingRequest nel client tier del PostbackManager. Così come per le richieste trasmesse chiamando doAsyncRequest, anche queste si possono gestire nell'evento RequestReceived lato web.
Le risposte alle richieste del controllo Web ADF possono essere processate tramite l'evento requestProcessed lato client.
Si può rendere disponibile questa funzionalità semplicente aggiungendo un PostbackManager alla pagina.

Per i dettagli vedere qui.

Nel MapResourceManager definiamo un layer di tipo GraphicLayer nominandolo 'Client Rendered Graphics' ed uno di tipo ArcGIS Server Internet da http://sampleserver1.arcgisonline.com/ArcGIS/services ( Specialty/ESRI_StatesCitiesRivers_USA ). Al di sotto di una certa scala (nell'esempio a 7.000.000) visualizziamo le città con delle icone in funzione della popolazione del 1990 (>32000 abitanti icone blu altrimenti magenta) con un mapTip formattato lato client e dove è possibile, ad esempio, gestire in base a determinate condizioni.

Lato server:

public partial class _Default : System.Web.UI.Page

    {

        private bool _hasNonPooledResources = false;

        #region Page Methods

        protected void Page_Load(object sender, EventArgs e)

        {

            if (!Page.IsPostBack)

            {

                if (Map1.MapResourceManager == null || Map1.MapResourceManager.Length == 0)

                    callErrorPage("No Map Resource Manager defined for the Map.", null);

                if (MapResourceManager1.ResourceItems.Count == 0)

                    callErrorPage("The Map Resource Manager does not have a valid Resouce Item.", null);

                if (Map1.PrimaryMapResourceInstance == null)

                    callErrorPage("The Map does not have a valid Primary Map Resource.", null);

            }

            // Check for locale decimal delimiter and pass to client side

            string delimiterScript = "var webMapAppDecimalDelimiter = '" + GetDecimalSeparatorFromLocale() + "';";

            if (!Page.ClientScript.IsClientScriptBlockRegistered("decimalDelimiterScript"))

                Page.ClientScript.RegisterClientScriptBlock(Page.GetType(), "decimalDelimiterScript", delimiterScript, true);

            PostbackManager1.RequestReceived += new RequestReceivedEventHandler(PostbackManager1_RequestReceived);

        }

        void PostbackManager1_RequestReceived(object sender, AdfRequestEventArgs args)

        {

            // Make sure request was issued by PostbackManager

            if (args.CallingControl.ClientID == "PostbackManager1")

            {

                NameValueCollection requestArgs =

                    CallbackUtility.ParseStringIntoNameValueCollection(args.RequestArguments);

                if (requestArgs["EventArg"] == "Type") // Request for client-rendered county graphic (i.e. map tip)

                {

                    IMapFunctionality mapFunctionality = Map1.GetFunctionality("Test");

                    IMapFunctionality mapFunctionality1 = Map1.GetFunctionality("Client Rendered Graphics");

                    ESRI.ArcGIS.ADF.Web.DataSources.Graphics.MapResource mapResource =

                            mapFunctionality1.Resource as ESRI.ArcGIS.ADF.Web.DataSources.Graphics.MapResource;

                    if (Map1.Scale > 7000000.0)

                    {

                        mapResource.Graphics.Clear();

                        Map1.RefreshResource("Client Rendered Graphics");

                        PostbackManager1.CallbackResults.CopyFrom(Map1.CallbackResults);

                        return;

                    }

                    // Create functionality to query Operational resource

                    IGISResource gisResource = mapFunctionality.Resource;

                    IQueryFunctionality queryFunctionality =

                        gisResource.CreateFunctionality(typeof(IQueryFunctionality), null) as

                        IQueryFunctionality;

                    NumberFormatInfo nfi = new CultureInfo("en-US").NumberFormat;

                    double x1 = double.Parse(requestArgs["XMIN"],nfi);

                    double y1 = double.Parse(requestArgs["YMIN"],nfi);

                    double x2 = double.Parse(requestArgs["XMAX"], nfi);

                    double y2 = double.Parse(requestArgs["YMAX"], nfi);

                    // Create spatial query filter

                    ESRI.ArcGIS.ADF.Web.SpatialFilter spatialFilter =

                        new ESRI.ArcGIS.ADF.Web.SpatialFilter();

                    spatialFilter.SubFields = new ESRI.ArcGIS.ADF.StringCollection(

                        new string[] { "FID", "CITY_FIPS", "CITY_NAME", "POP1990" });

                    spatialFilter.ReturnADFGeometries = true;

                    spatialFilter.Geometry = new ESRI.ArcGIS.ADF.Web.Geometry.Envelope(x1,y1,x2,y2); 

                    // Execute query against counties layer

                    DataTable resultsDataTable =

                        queryFunctionality.Query(mapFunctionality.Name, "0", spatialFilter);

                    // Create graphics and apply Operational resource's layer definitions

                    GraphicsLayer resultsGraphicsLayer =

                        ESRI.ArcGIS.ADF.Web.Converter.ToGraphicsLayer(resultsDataTable,

                        System.Drawing.Color.Empty, System.Drawing.Color.Empty,

                        System.Drawing.Color.Empty, true);

                    resultsGraphicsLayer.TableName = "find_Cities";

                    // Render on client to enable highlighting and MapTips

                    resultsGraphicsLayer.RenderOnClient = true;

                    // Add tipo to Graphics resource

                    if (mapResource.Graphics.Tables.Contains("find_Cities"))

                        mapResource.Graphics.Tables.Remove("find_Cities");

                    mapResource.Graphics.Tables.Add(resultsGraphicsLayer);

                    // Refresh the graphics and pass the results to the PostbackManager

                    Map1.RefreshResource("Client Rendered Graphics");

                    // Use the CustomResults property to pass the client ID of the graphics layer back to the

                    // client.  This property is used in the processResults function.

                    if (resultsGraphicsLayer.Rows.Count > 0)

                    {

                        PostbackManager1.CustomResults = Map1.GetGraphicsLayerClientID(resultsGraphicsLayer);

                    }

                }

                PostbackManager1.CallbackResults.CopyFrom(Map1.CallbackResults);

            }

        }

Lato client:

<script language="javascript" type="text/javascript">

  Sys.Application.add_init(function() {

  // Get map and wire MapTips events

  var map = $find('Map1');

  map.add_extentChanged(MapChanged);

  // Specify handler for requestProcessed

  ESRI.ADF.Samples.PostbackManager.add_requestProcessed(processResults);

  });

  function MapChanged(sender, eventArgs){

  var requestArgs = 'EventArg=Type&XMIN={0}&YMIN={1}&XMAX={2}&YMAX={3}';

  var envelope = eventArgs.current;

  requestArgs = String.format(requestArgs, envelope.get_xmin(),envelope.get_ymin(),envelope.get_xmax(),envelope.get_ymax());

  ESRI.ADF.Samples.PostbackManager.doAsyncRequest(requestArgs);

  }

  // Handle results to show map tip and disable subsequent requests

  function processResults(sender, eventArgs) {

  if (eventArgs.customResults) {

  if (eventArgs.customResults == "Clear") {

  return;

  }

  var graphicFeatureGroup = $find(eventArgs.customResults);

  var defaultSymbol11 = new ESRI.ADF.Graphics.MarkerSymbol('images/pin-blue-20x20.png', 10, 10, 'default');

  var defaultSymbol12 = new ESRI.ADF.Graphics.MarkerSymbol('images/pin-blue-28x28.png', 14, 14, 'default');

  defaultSymbol11.set_opacity(0.8);

  defaultSymbol11.set_height(20);

  defaultSymbol12.set_opacity(0.8);

  defaultSymbol12.set_height(28);

  var defaultSymbol21 = new ESRI.ADF.Graphics.MarkerSymbol('images/pin-magenta-20x20.png', 10, 10, 'default');

  var defaultSymbol22 = new ESRI.ADF.Graphics.MarkerSymbol('images/pin-magenta-28x28.png', 14, 14, 'default');

  defaultSymbol21.set_opacity(0.8);

  defaultSymbol21.set_height(20);

  defaultSymbol22.set_opacity(0.8);

  defaultSymbol22.set_height(28);

  for (var i=0;i<graphicFeatureGroup.getFeatureCount();i++)

               {

                   var graphicFeature = graphicFeatureGroup.get(i);

                   if (graphicFeature.get_attributes().POP1990 > 32000.0)

    {

    graphicFeature.set_selectedSymbol(defaultSymbol11);

    graphicFeature.set_highlightSymbol(defaultSymbol12);

    }

    else

    {

    graphicFeature.set_selectedSymbol(defaultSymbol21);

    graphicFeature.set_highlightSymbol(defaultSymbol22);

    }

    }

    var layout = {

    'template': null,

    'templateUrl': 'Template.htm',

    'arrowUrl': 'images/square-red-32x32.png',

    'arrowBounds': [

    // startX,startY,width,height,offsetX,offsetY,bufferX,bufferY

    [954, 921, 16, 16, -1, -7, 5, -7], // NW - Upper Left

    [939, 921, 16, 16, -15, -7, 5, -7], // NE - Upper Right

    [954, 921, 16, 16, -1, -23, 5, -7], // SW - Lower Left

    [939, 921, 16, 16, -15, -23, 5, -7]  // SE - Lower Right

    ]

    };

    var mapTips = graphicFeatureGroup.get_mapTips();

    //mapTips.set_width(100); //set larghezza

    mapTips.set_layout(layout);

    // Initialize a string containing the format for the MapTips title. The appearance can be

    // specified using HTML and CSS.  Field names surrounded with curly braces and preceded with

    // an @ are substituted at run-time with the corresponding field value of the feature on which

    // a MapTip is currently shown.  In this example, the AREANAME field is shown.

    var titleTemplate = "<font style='font-family:MS Sans Serif; color:blue; font-size:14pt;'>{@FID}</font>";

    // Initialize a string containing the format for the MapTips contents.

    var contentTemplate = "<table cellpadding='3px'>

      <tr>

        " +

        "<td style='border-bottom:1px solid gray; border-right:1px solid gray; font-weight:bold;'>

          " +

          "CITY_FIPS

        </td>" +

        "<td style='border-bottom:1px solid gray; border-right:1px solid gray; font-style:italic; " +

                "color:green;'>{@CITY_FIPS}</td>

      </tr>" +

      "<tr>

        <td style='border-bottom:1px solid gray; border-right:1px solid gray; font-weight:bold;'>

          " +

          "CITY_NAME

        </td>" +

        "<td style='border-bottom:1px solid gray; border-right:1px solid gray; font-style:italic;" +

                "color:green;'>{@CITY_NAME}</td>

      </tr>

    </table>";

    // Apply the title and content formats

    mapTips.set_hoverTemplate(titleTemplate);

    mapTips.set_contentTemplate(contentTemplate);

    }

    }

  </script>

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