// Copyright 2011 ESRI
// 
// All rights reserved under the copyright laws of the United States
// and applicable international laws, treaties, and conventions.
// 
// You may freely redistribute and use this sample code, with or
// without modification, provided you include the original copyright
// notice and use restrictions.
// 
// See the use restrictions.
// 

public partial class Default : System.Web.UI.Page, IBaseToolbarRefresh
{
    #region ASP.NET Page Event Handlers

    protected void Page_Init(object sender, System.EventArgs e)
    {
        
        // Used to determine if a previous/next action occurred
        if (!IsPostBack)
        {
            Session["previousNext"] = false;
            Session["previousNextMapHandler"] = false;
        }
    }

    #endregion

    #region Web ADF Control Event Handlers

    protected void Map1_ExtentChanged(object sender, 
        ESRI.ArcGIS.ADF.Web.UI.WebControls.ExtentEventArgs extentEventArgs)
    {
        // PreviousNext session variable tracks if a Previous or Next command was initiated to change extent
        if (Session["previousNext"] != null)
        {
            try
            {
                bool isPreviousNext = (bool)Session["previousNext"];
                bool isPreviousNextMapHandler = (bool)Session["previousNextMapHandler"];

                // If Previous or Next command, isPreviousNext is true.  Reset session variable to false
                if (isPreviousNext)
                {
                    // Reset to false
                    Session["previousNext"] = false;
                }
                else if (isPreviousNextMapHandler)
                {
                    Session["previousNextMapHandler"] = false;
                }
                // If another event changed the map extent, do the following
                else
                {
                    // On initial load, create the hashtable to store extent Envelopes or get session variable
                    System.Collections.Hashtable extentsHashTable = null;
                    if (Session["extentHistory"] != null)
                    {
                        extentsHashTable = (System.Collections.Hashtable)Session["extentHistory"];
                    }
                    else
                    {
                        extentsHashTable = new System.Collections.Hashtable();
                    }

                    // Track the index of the current extent, if first extent the index is 0
                    int currentExtentIndex = 0;
                    if (Session["currentExtentIndex"] != null)
                    {
                        currentExtentIndex = (int)Session["currentExtentIndex"];
                    }
                    else
                    {
                        Session["currentExtentIndex"] = 0;
                    }

                    // If current index is less than highest index in the extent history, continue
                    int removeFromExtentIndex = 1;
                    if (currentExtentIndex < (extentsHashTable.Count - 1))
                    {
                        // Since another event triggered the extent change (not Previous or Next)
                        // we need to delete the extents in front of the current index
                        for (int i = extentsHashTable.Count - 1; i > currentExtentIndex; i--)
                        {
                            extentsHashTable.Remove(i);
                            removeFromExtentIndex++;
                        }

                        // Disable NextExtent command
                        Map1.CallbackResults.CopyFrom(RefreshToolbar("nextExtent", true));
                    }

                    // Add current extent to the hashtable, htExtents.Count is 0 for the first extent
                    // added to the array
                    extentsHashTable.Add(extentsHashTable.Count, extentEventArgs.NewExtent);

                    // Extent index is a 0-based array
                    Session["currentExtentIndex"] = extentsHashTable.Count - 1;

                    // Store extent Envelopes in an hashtable
                    Session["extentHistory"] = extentsHashTable;

                    // Enable PreviousExtent command if number of extents is greater than 1
                    if (extentsHashTable.Count > 1)
                    {
                        Map1.CallbackResults.CopyFrom(RefreshToolbar("previousExtent", false));
                    }
                }
            }
            catch (System.Exception exception)
            {
                ESRI.ArcGIS.ADF.Web.UI.WebControls.CallbackResult errorCallbackResult =
                    CustomToolLibrary.Utility.GetErrorCallback(exception);
                Map1.CallbackResults.Add(errorCallbackResult);
            }
        }
    }

    #endregion

    #region Instance Methods

    public ESRI.ArcGIS.ADF.Web.UI.WebControls.CallbackResultCollection RefreshToolbar(string toolItemName, 
        bool disabled)
    {
        try
        {
            // Enable\disable toolbar item on the server
            ESRI.ArcGIS.ADF.Web.UI.WebControls.ToolbarItemCollection toolbarItemCollection = Toolbar2.ToolbarItems;
            ESRI.ArcGIS.ADF.Web.UI.WebControls.Command command = null;
            foreach (ESRI.ArcGIS.ADF.Web.UI.WebControls.ToolbarItem toolbarItem in toolbarItemCollection)
            {
                if (toolbarItem.Name == toolItemName)
                {
                    command = (ESRI.ArcGIS.ADF.Web.UI.WebControls.Command)toolbarItem;
                    if (command.Disabled != disabled)
                    {
                        if (disabled)
                            command.Disabled = true;
                        else
                            command.Disabled = false;

                        Toolbar2.Refresh();

                        // Enable/disable toolbar item on the client (browser)
                        string jsToolbarItemEnable = "var toolbar = Toolbars['" + Toolbar2.ClientID +
                            "']; var toolbaritem = toolbar.items['" + command.Name +
                            "'];toolbaritem.disabled = " + command.Disabled.ToString().ToLower() + ";";
                        ESRI.ArcGIS.ADF.Web.UI.WebControls.CallbackResult enableToolbarItemCallbackResult =
                            ESRI.ArcGIS.ADF.Web.UI.WebControls.CallbackResult.CreateJavaScript(
                            jsToolbarItemEnable);
                        Toolbar2.CallbackResults.Add(enableToolbarItemCallbackResult);
                    }
                }
            }
        }
        catch (System.Exception exception)
        {
            ESRI.ArcGIS.ADF.Web.UI.WebControls.CallbackResult errorCallbackResult =
                CustomToolLibrary.Utility.GetErrorCallback(exception);
            Toolbar2.CallbackResults.Add(errorCallbackResult);
        }

        return Toolbar2.CallbackResults;
    }

    #endregion
}