SharePoint 2013 App Development Sample (a) List read-write

In this example, we will create a page to test the permissions of the SharePoint app. This page has two buttons, one reads data from documents and one writes data to documents:

1. Open Visual Studio 2012, create a new Sharepoint 2013 app:permissiontest, select sharepoint-hosted, click Finish

2. Open default.aspx:

Introduction of Knockoutjs

<script type= "Text/javascript" src= "Https://ajax.aspnetcdn.com/ajax/knockout/knockout-2.2.1.js" ></ Script>

Add two buttons:

<asp:content id= "Content2" contentplaceholderid= "Placeholderpagetitleintitlearea" runat= "Server" >
   App Permission Test
</asp:Content>
<asp:content id= "Content3" contentplaceholderid= "PlaceHolderMain" runat= "Server" >
   <button data-bind= "Click:readlist" >press here to read from documents.</button>
   <br  />
   <button data-bind= "Click:writelist" >press here to write to documents.</button>
</asp:Content>

3. Open App.js, add the following JS:

<reference path= "Knockout-3.0.0.debug.js"/> $ (function () {ko.applybindings (new Testpermissionsviewmodel
());
   
});
    function Testpermissionsviewmodel () {var self = this;
   
    Self.result = null; Self.readlist = function () {var context = new SP.
        Clientcontext.get_current (); var hostwebcontext = new SP.
        Appcontextsite (Context, decodeURIComponent (Getquerystringparameter ("Sphosturl")); Self.result = Hostwebcontext.get_web (). Get_lists (). Getbytitle ("Documents"). GetItems (New SP.
        Camlquery.createallitemsquery ());
        Context.load (Self.result); Context.executequeryasync (Function.createdelegate (self, self.onsuccess), Function.createdelegate (
    Self, self.onfail)); } self.writelist = function () {var context = new SP.
        Clientcontext.get_current (); var hostwebcontext = new SP.
        Appcontextsite (Context, decodeURIComponent (Getquerystringparameter ("Sphosturl")); Self.result = Hostwebcontext.get_web (). Get_lists (). Getbytitle ("Documents"). GetItemByID (1);
        Self.result.set_item ("title", "My Update book Title");
        Self.result.update (); Context.executequeryasync (Function.createdelegate (self, self.onsuccess), Function.createdelegate (
    Self, self.onfail)); } self.onsuccess = function () {if (Self.result instanceof SP).
            ListItemCollection) {if (!self.result.get_item (0)) {alert ("Success but no return");
            else {alert ("Success, title =" + Self.result.get_item (0). get_item ("title"));
        } else {alert ("Success");
    } self.onfail = function (sender, args) {alert ("Failed:" + args.get_message ()); } function Getquerystringparameter (paramtoretrieve) {var params = document. Url.split ("?")
    [1].split ("&"); var strparams ="";
        for (var i = 0; i < params.length i = i + 1) {var singleparam = params[i].split ("=");
    if (singleparam[0] = = Paramtoretrieve) return singleparam[1]; }
}