Open and Save Presentation in DropBox Cloud Storage

4 Feb 202513 minutes to read

Prerequisites

Create a DropBox API App, by following the official documentation provided by DropBox link. The process involves visiting the DropBox Developer website and using their App Console to set up your API app. This app will allow you to interact with DropBox programmatically, enabling secure access to files and data.

Open Presentation from DropBox Cloud Storage

Steps to open a Presentation from DropBox Cloud Storage.

Step 1: Create a new ASP.NET Core Web Application (Model-View-Controller).

Create a ASP.NET Core Web App project in visual studio

Step 2: Name the project.

Name the project

Step 3: Install the following Nuget packages in your application from NuGet.org.

Install Syncfusion.Presentation.Net.Core NuGet Package
Install Dropbox.Api NuGet Package

Step 4: Add a new button in the Index.cshtml as shown below.

CSHTML
@{Html.BeginForm("EditDocument", "Home", FormMethod.Get);
    {
        <div>
            <input type="submit" value="Edit Document" style="width:150px;height:27px" />
        </div>
    }
    Html.EndForm();
}

Step 5: Include the following namespaces in HomeController.cs.

C#
using Dropbox.Api;
using Syncfusion.Presentation;

Step 6: Include the below code snippet in HomeController.cs to open a Presentation from DropBox Cloud Storage.

C#
public async Task<IActionResult> EditDocument()
{
    try
    {
        //Retrieve the document from DropBox
        MemoryStream stream = await GetDocumentFromDropBox();

        //Set the position to the beginning of the MemoryStream
        stream.Position = 0;

        //Create an instance of PowerPoint Presentation file
        using (IPresentation pptxDocument = Presentation.Open(stream))
        {
            //Get the first slide from the PowerPoint presentation
            ISlide slide = pptxDocument.Slides[0];

            //Get the first shape of the slide
            IShape shape = slide.Shapes[0] as IShape;

            //Change the text of the shape
            if (shape.TextBody.Text == "Company History")
                shape.TextBody.Text = "Company Profile";

            //Saving the PowerPoint file to a MemoryStream 
            MemoryStream outputStream = new MemoryStream();
            pptxDocument.Save(outputStream);

            //Download the PowerPoint file in the browser
            FileStreamResult fileStreamResult = new FileStreamResult(outputStream, "application/powerpoint");
            fileStreamResult.FileDownloadName = "EditPowerPoint.pptx";
            return fileStreamResult;
        }
    }
    catch (Exception ex)
    {
        Console.WriteLine($"Error: {ex.Message}");
        return Content("Error occurred while processing the file.");
    }
}

Download file from DropBox cloud storage

This is the helper method to download Presentation from DropBox cloud storage.

C#
/// <summary>
/// Download file from DropBox cloud storage
/// </summary>
/// <returns></returns>
public async Task<MemoryStream> GetDocumentFromDropBox()
{
    //Define the access token for authentication with the Dropbox API
    var accessToken = "Access_Token";

    //Define the file path in Dropbox where the file is located. For ex: "/Template.pptx" or "/Apps/Template.pptx"
    var filePathInDropbox = "FilePath";

    try
    {
        //Create a new DropboxClient instance using the provided access token
        using (var dbx = new DropboxClient(accessToken))
        {
            //Start a download request for the specified file in Dropbox
            using (var response = await dbx.Files.DownloadAsync(filePathInDropbox))
            {
                //Get the content of the downloaded file as a stream
                var content = await response.GetContentAsStreamAsync();

                MemoryStream stream = new MemoryStream();
                content.CopyTo(stream);
                return stream;
            }
        }
    }
    catch (Exception ex)
    {
        Console.WriteLine($"Error retrieving document from DropBox: {ex.Message}");
        throw; // or handle the exception as needed
    }
}

You can download a complete working sample from GitHub.

By executing the program, you will get the Presentation as follows.

Output Presentation

Save Presentation to DropBox Cloud Storage

Steps to save a Presentation to DropBox Cloud Storage.