Q:

UWP - How to Sync files with OneDrive API in C#

I am creating a UWP application and I want to use the Onedrive API so that users can save a copy of their files in their Onedrive account, but I don't get it, so far I have only managed to login what I want is:

upload files
download files
and synchronize if any of them is modified
Create folders
Delete Files

This code achieves the login, but I can not move beyond this, as would proceed for upload files or download them
 private async void btn_Login_Click(object sender, RoutedEventArgs e)
        {
            if (this.oneDriveClient == null)
            {
                try
                {
                    // Setting up the client here, passing in our Client Id, Return Url, 
                    // Scopes that we want permission to, and building a Web Broker to 
                    // go do our authentication.  

                    this.oneDriveClient = await OneDriveClient. GetAuthenticatedMicrosoftAccountClient(
                        clientId,
                        returnUrl,
                        scopes,
                        webAuthenticationUi: new WebAuthenticationBrokerWebAuthenticationUi());

                   // Show in text box that we are connected. 
                   txtBox_Response. Text = "We are now connected";

                    // We are either just autheticated and connected or we already connected, 
                    // either way we need the drive button now. 
                    btn_GetDriveId. Visibility = Visibility. Visible;
                }
                catch (OneDriveException exception)
                {
                    // Eating the authentication cancelled exceptions and resetting our client.  
                    if (! exception. IsMatch(OneDriveErrorCode. AuthenticationCancelled. ToString()))
                    {
                        if (exception. IsMatch(OneDriveErrorCode. AuthenticationFailure. ToString()))
                        {
                            txtBox_Response. Text = "Authentication failed/cancelled, disposing of the client...";

                            ((OneDriveClient)this.oneDriveClient).Dispose();
                            this.oneDriveClient = null;
                        }
                        else
                        {
                            // Or we failed due to someother reason, let get that exception printed out. 
                            txtBox_Response. Text = exception. Error. ToString();
                        }
                    }
                    else
                    {
                        ((OneDriveClient)this.oneDriveClient).Dispose();
                        this.oneDriveClient = null;
                    }
                }
            }
        }

I created a sample repository in github:Onedrive Sync Files Sample
I have already tried using Dropbox, Gdrive, but its implementation for UWP seems to be much more complex, so I chose OneDrive.  any answer will be very helpful thanks in advance

A:

How to Sync files with OneDrive API in C#

For using OneDrive, we suggest you implement OneDrive feature with OneDrive Service that is part of Windows Community Toolkit . 
Getting Started
To use the OneDrive API, you need to have an access token that authenticates your app to a particular set of permissions for a user.  In this section, you'll learn how to:

Register your application to get a client ID and a client secret. 
Sign your user in to OneDrive with the specified scopes using the token flow or code flow. 
Sign the user out (optional). 

And this is official code sample that you could refer.