How to Build a CRUD App with Xamarin?

overview this guide will walk you through the creation of a complete crud (create, read, update, delete) application using xamarin we will utilize back4app as our backend service to effortlessly manage your data throughout this tutorial, you'll see how to configure a back4app project, set up a flexible data schema, and implement crud operations in a xamarin application initially, you'll configure a back4app project named basic crud app xamarin this project will serve as the robust backend for your application you’ll define your data structures manually through the back4app dashboard or leverage the built in ai agent next, you will harness the intuitive back4app admin app to manage your data effortlessly via drag and drop functionality finally, you will integrate your xamarin app with back4app using the parse net sdk, which is fully compatible with xamarin, ensuring secure and efficient data operations by the conclusion of this tutorial, you will have developed a production ready xamarin application capable of executing basic crud operations along with secure user authentication and data management key insights learn how to construct a xamarin based crud app integrated with a robust non relational backend understand how to design a scalable backend and connect it seamlessly with your xamarin app discover how to manage crud operations using the back4app admin app explore options for secure user management and backend security using acls and clps prerequisites before you begin, make sure you have a back4app account with a configured project for help, refer to getting started with back4app https //www back4app com/docs/get started/new parse app a xamarin development environment install visual studio with xamarin support and ensure you have the latest net sdk a basic understanding of c#, object oriented programming, and rest apis you can review the microsoft c# documentation https //docs microsoft com/en us/dotnet/csharp/ if needed step 1 – configuring your back4app project creating a new project on back4app log in to your back4app account click the “new app” button on your dashboard name your project basic crud app xamarin and follow the on screen instructions to complete the setup create new project after your project is successfully created, it will appear on your dashboard, ready for further backend configuration step 2 – crafting the data schema defining your data structures for this crud application, you need to set up several classes (collections) in your back4app project below are examples of the primary classes and their respective fields that you’ll create 1\ items class field data type description id objectid auto generated unique identifier title string the item’s name description string a brief summary of the item createdat date timestamp marking creation updatedat date timestamp marking the last update 2\ users class field data type description id objectid automatically generated unique id username string unique username for the user email string unique email address for account contact passwordhash string encrypted password for security createdat date account creation timestamp updatedat date timestamp for the last account update you can add these classes and fields manually via the back4app dashboard create new class you can define each field by selecting a data type, entering the field name, setting default values, and marking mandatory fields create column utilizing the back4app ai agent for schema generation the integrated ai agent in your back4app dashboard can automatically generate your data schema based on a description this tool simplifies the setup process and guarantees that your data model is optimized for crud operations how to use the ai agent access the ai agent open your back4app dashboard and locate the ai agent within your project settings describe your schema provide a detailed outline of the classes and fields you need review and implement the ai agent will propose a schema examine the suggested configuration and approve it to apply the changes example prompt create the following classes in my back4app project 1\) class items \ fields \ id objectid (auto generated) \ title string \ description string \ createdat date (auto generated) \ updatedat date (auto updated) 2\) class users \ fields \ id objectid (auto generated) \ username string (unique) \ email string (unique) \ passwordhash string \ createdat date (auto generated) \ updatedat date (auto updated) this ai assisted method saves time and ensures a consistent, optimized data structure step 3 – enabling the admin app & managing crud operations overview of the admin app the back4app admin app provides a no code interface for easy backend data management its drag and drop interface simplifies crud operations such as creating, reading, updating, and deleting records enabling the admin app open the “more” menu on your back4app dashboard select “admin app” and click “enable admin app ” set up your admin credentials by creating an initial admin account this process also establishes predefined roles (e g , b4aadminuser ) and system classes enable admin app once activated, sign in to the admin app to begin managing your app’s data admin app dashboard performing crud operations with the admin app inside the admin app, you can insert new data use the “add record” feature within any class (e g , items) to create new entries view and edit records select a record to inspect details or modify fields delete records remove data entries that are no longer required this user friendly interface streamlines the process of managing your backend step 4 – connecting your xamarin app to back4app with your backend ready, the next task is to link your xamarin application to back4app option a using the parse net sdk in xamarin add the parse net sdk dependency for a xamarin project, include the parse net sdk via nuget open your nuget package manager and install install package parse initialize parse in your xamarin app create an initialization file (e g , parseinitializer cs ) and configure it as follows // parseinitializer cs using parse; public static class parseinitializer { public static void initialize() { parseclient initialize(new parseclient configuration { applicationid = "your application id", windowskey = "your xamarin key", server = "https //parseapi back4app com" }); } } 3\ implement crud operations for example, create a service class to manage items ```csharp // itemsservice cs using parse; using system; using system collections generic; using system threading tasks; public class itemsservice { public async task\<list\<parseobject>> getitemsasync() { var query = new parsequery\<parseobject>("items"); try { return await query findasync(); } catch (exception ex) { console writeline($"error fetching items {ex message}"); return null; } } public async task createitemasync(string title, string description) { var item = new parseobject("items"); item\["title"] = title; item\["description"] = description; try { await item saveasync(); console writeline("item created successfully "); } catch (exception ex) { console writeline($"error creating item {ex message}"); } } public async task updateitemasync(string objectid, string newtitle, string newdescription) { var query = new parsequery\<parseobject>("items"); try { var item = await query getasync(objectid); item\["title"] = newtitle; item\["description"] = newdescription; await item saveasync(); console writeline("item updated successfully "); } catch (exception ex) { console writeline($"error updating item {ex message}"); } } public async task deleteitemasync(string objectid) { var query = new parsequery\<parseobject>("items"); try { var item = await query getasync(objectid); await item deleteasync(); console writeline("item deleted successfully "); } catch (exception ex) { console writeline($"error deleting item {ex message}"); } } } option b using rest or graphql if the parse net sdk is not preferred, you can implement crud operations via rest calls for instance, to retrieve items using rest in a xamarin app using system; using system io; using system net http; using system threading tasks; public class restclient { private static readonly httpclient client = new httpclient(); public async task fetchitemsasync() { try { var request = new httprequestmessage(httpmethod get, "https //parseapi back4app com/classes/items"); request headers add("x parse application id", "your application id"); request headers add("x parse rest api key", "your rest api key"); var response = await client sendasync(request); response ensuresuccessstatuscode(); var responsebody = await response content readasstringasync(); console writeline($"response {responsebody}"); } catch (exception ex) { console writeline($"error fetching items {ex message}"); } } } integrate these api calls within your xamarin project as necessary step 5 – enhancing backend security configuring access control lists (acls) secure your data by setting acls on your objects for example, to create an item accessible only by its owner using parse; using system; public async task createprivateitemasync(string title, string description, parseuser owner) { var item = new parseobject("items"); item\["title"] = title; item\["description"] = description; var acl = new parseacl(owner); acl publicreadaccess = false; acl publicwriteaccess = false; item acl = acl; try { await item saveasync(); console writeline("private item created successfully "); } catch (exception ex) { console writeline($"error saving private item {ex message}"); } } setting class level permissions (clps) within your back4app dashboard, configure clps to establish default access rules this ensures that only authenticated users can interact with specific classes step 6 – implementing user authentication in xamarin managing user accounts back4app utilizes the built in parse user class for authentication in your xamarin app, manage user registration and login as shown below using parse; using system; public class authservice { public async task signupasync(string username, string password, string email) { var user = new parseuser { username = username, password = password, email = email }; try { await user signupasync(); console writeline("user registered successfully!"); } catch (exception ex) { console writeline($"error during sign up {ex message}"); } } public async task loginasync(string username, string password) { try { var user = await parseuser loginasync(username, password); console writeline($"user logged in {user username}"); } catch (exception ex) { console writeline($"login failed {ex message}"); } } } this approach can be extended to include session management, password recovery, and other authentication related functionalities step 7 – conclusion and future directions well done! you have successfully developed a xamarin based crud application integrated with back4app in this tutorial, you configured a back4app project named basic crud app xamarin designed the necessary data structures for items and users leveraged the back4app admin app to manage your data connected your xamarin application via the parse net sdk (or rest/graphql) to perform crud operations implemented robust security measures including acls and clps set up user authentication to manage account creation and login next steps expand the app functionality consider adding features like advanced filtering, detailed item views, or real time data updates enhance backend capabilities explore cloud functions, third party integrations, and role based access controls further learning visit the back4app documentation https //www back4app com/docs and additional resources to optimize and scale your application happy coding and best of luck with your xamarin crud application!