LightSwitch Help Website > Blog - Automatic Save (And Refresh)

** THIS SITE IS AN ARCHIVE ** - New Content is at:

Keywords

Phrase

Automatic Save (And Refresh)

Jan 6

Written by: Michael Washington
1/6/2013 6:57 PM

Automatic Save (And Refresh)

At the time of this writing, the LightSwitch HTML Client is still in preview. We can expect additional functionality in the future release. For now, any updates to the data require the user to explicitly press the save button. This is not optimal in all situations.

For example, we now desire the ability to delete all the sales records for a single sales person, then automatically switch back to the main page. To implement this, we can use the method described in the article Retrieving The Current User In The LightSwitch HTML Client.

First we switch to File View.

We then add a page to the Server project using the following code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
namespace LightSwitchApplication.Web
{
    public class DeleteRecords : IHttpHandler
    {
        public void ProcessRequest(HttpContext context)
        {
            // Get the LightSwitch serverContext
            using (var serverContext = ServerApplicationContext.CreateContext())
            {
                // Minimal security is to check for IsAuthenticated
                if (serverContext.Application.User.IsAuthenticated)
                {
                    if (context.Request.QueryString["SalesPersonId"] != null)
                    {
                        // The Salesperson was passed as a parameter
                        // Note that better security would be to check if the current user
                        // should have the ability to delete the records
                        // 'serverContext.Application.User.Name' returns the current user
                        int intSalesPersonId = Convert.ToInt32(context.Request.QueryString["SalesPersonId"]);
                        // Get the Sales records to delete
                        var result = from Sales in serverContext.DataWorkspace.ApplicationData
                                         .SalesSet.GetQuery().Execute()
                                     where Sales.SalesPerson.Id == intSalesPersonId
                                     select Sales;
                        // Loop through each record found
                        foreach (var item in result)
                        {
                            // Delete the record
                            item.Delete();
                            // Save changes
                            serverContext.DataWorkspace.ApplicationData.SaveChanges();
                        }
                        // Return a response
                        // We could return any potential errors
                        context.Response.ContentType = "text/plain";
                        context.Response.Write("complete");
                    }
                }
            }
        }
        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }
}

(this code uses the new serverContext API)

We switch back to Logical View, open the AddEditSalesPerson screen, add a button, then select Edit Execute Code for the button.

We use the following code:

myapp.AddEditSalesPerson.DeleteAllSales_execute = function (screen) {
    // Get selected SalesPersonId
    var SalesPersonId = screen.SalesPerson.Id;
    $.ajax({
        type: 'post',
        data: {},
        url: '../web/DeleteRecords.ashx?SalesPersonId=' + SalesPersonId,
        success: function success(result) {
            // Navigate back to main page
            myapp.navigateBack();
        }
    });
};