Windows 8 Store Apps Learning (54) Binding: Incrementally loading Data

Introduced

Re-imagine the bindings of Windows 8 Store Apps

Provides data for incremental loading of listviewbase by implementing the Isupportincrementalloading interface

Example

Implements the Isupportincrementalloading interface to provide data for incremental loading of listviewbase

Binding/myincrementalloading.cs

* * Demonstrates how to implement the Isupportincrementalloading interface to provide data for incremental loading of listviewbase * isupportincrementalloading-for support of incremental loading * Hasmoreitems-Is there more data * iasyncoperation<loadmoreitemsresult> Loadmoreitemsasync (UINT count)-asynchronously loading a specified number of
Data (incremental load) * * Loadmoreitemsresult-the result of the incremental load * Count-the amount of data actually loaded */using System;
Using System.Collections.Generic;
Using System.Collections.ObjectModel;
Using System.Runtime.InteropServices.WindowsRuntime;
Using System.Threading.Tasks;
Using Windows.foundation;
Using Windows.UI.Core;
Using Windows.UI.Xaml;
    
Using Windows.UI.Xaml.Data; Namespace Xamldemo.binding {public class myincrementalloading<t>: Observablecollection<t>, isupportinc
    
        rementalloading {//whether the private bool _isbusy = False is being loaded asynchronously;  Provides the Func//first parameter of the data: The starting index of the incremental load; the second parameter: The amount of data to be fetched; third parameter: Gets the data collection private func<int, int, list<t>>
        _funcgetdata; Maximum amount of data available private UINT _totAlcount = 0; <summary>///Constructor///</summary>///<param name= "totalcount" > Maximum amount of data < /param>///<param name= "Getdatafunc" > Provide data func</param> public myincrementalloading (UINT t
            Otalcount, Func<int, int, list<t>> getdatafunc) {_funcgetdata = Getdatafunc;
        _totalcount = TotalCount;
        ///<summary>///Do you have more data///</summary> public bool Hasmoreitems {get {return this. Count < _totalcount; }///<summary>///asynchronous Load data (incremental load)///</summary>///<param N Ame= "Count" > amount of data to load </param>///<returns></returns> public IASYNCOPERATION&LT;LOADMO Reitemsresult> Loadmoreitemsasync (UINT count) {if (_isbusy) {throw New INVALIDOPERATIONEXCEPtion ("Busy, ignore you first");
    
            } _isbusy = true;
    
            var dispatcher = Window.Current.Dispatcher;
                       return Asyncinfo.run (token) => task.run<loadmoreitemsresult> (
                               Async () => {try {
    
                               Simulate long time task await task.delay (1000); Incremental load starting index var startIndex = this.
    
                               Count; Await dispatcher.
                                    Runasync (Coredispatcherpriority.normal, () =>
                                        {//Get incremental data through Func
                                        var items = _funcgetdata (StartIndex, (int) count); foreach (Var item inItems) {this.
                                        ADD (item);
    
                               }
                                    }); Count-The amount of data actually loaded return the new Loadmoreitemsresult {Count = (UINT) this.
                           Count};
                           finally {_isbusy = false;
        }}, token)); }
    }
}