Loading and Saving Excel document in Dropbox Cloud Storage

29 Nov 202420 minutes to read

Prerequisites

  • Create a Dropbox API app using the Dropbox Developer website.
  • Use the App Console to set up your API app for secure access to Dropbox files and data.

Loading Excel document from Dropbox

Steps to load an Excel document 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.XlsIO.Net.Core NuGet Package
Install Dropbox.API NuGet Package

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

@{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.

using Dropbox.Api;
using Syncfusion.XlsIO;
using Syncfusion.Drawing;

Step 6: Include the below code snippet in HomeController.cs to load an Excel document from Dropbox Cloud Storage.

using (ExcelEngine excelEngine = new ExcelEngine())
{
    IApplication application = excelEngine.Excel;
    application.DefaultVersion = ExcelVersion.Xlsx;

    //Download the document from DropBox
    MemoryStream stream = await GetDocumentFromDropBox();

    //Set the position as '0'
    stream.Position = 0;

    //Load the downloaded document
    IWorkbook workbook = application.Workbooks.Open(stream);

    IWorksheet worksheet = workbook.Worksheets[0];
    worksheet.Range["A3"].Text = "Hello world";

    //Saving the Excel to the MemoryStream 
    MemoryStream outputStream = new MemoryStream();
    workbook.SaveAs(outputStream);

    //Set the position as '0'
    outputStream.Position = 0;

    //Download the Excel file in the browser
    FileStreamResult fileStreamResult = new FileStreamResult(outputStream, "application/excel");
    fileStreamResult.FileDownloadName = "EditExcel.xlsx";
    return fileStreamResult;
}

// Download file from DropBox
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.docx"
    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
    }
}

A complete working example of how to load an Excel document from Dropbox Cloud Storage in ASP.NET Core is present on this GitHub page.

By executing the program, you will get the Excel document as follows.

Output File

Saving Excel document to Dropbox

Steps to save an Excel document to 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.XlsIO.Net.Core NuGet Package
Install Dropbox.API NuGet Package

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

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

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

using Dropbox.Api;
using Syncfusion.XlsIO;
using Syncfusion.Drawing;

Step 6: Include the below code snippet in HomeController.cs to Save an Excel document to Dropbox Cloud Storage.

//Create an instance of ExcelEngine
using (ExcelEngine excelEngine = new ExcelEngine())
{
    IApplication application = excelEngine.Excel;
    application.DefaultVersion = ExcelVersion.Xlsx;

    //Create a workbook
    IWorkbook workbook = application.Workbooks.Create(1);
    IWorksheet worksheet = workbook.Worksheets[0];

    //Adding a picture
    FileStream imageStream = new FileStream("AdventureCycles-Logo.png", FileMode.Open, FileAccess.Read);
    IPictureShape shape = worksheet.Pictures.AddPicture(1, 1, imageStream, 20, 20);

    //Disable gridlines in the worksheet
    worksheet.IsGridLinesVisible = false;

    //Enter values to the cells from A3 to A5
    worksheet.Range["A3"].Text = "46036 Michigan Ave";
    worksheet.Range["A4"].Text = "Canton, USA";
    worksheet.Range["A5"].Text = "Phone: +1 231-231-2310";

    //Make the text bold
    worksheet.Range["A3:A5"].CellStyle.Font.Bold = true;

    //Merge cells
    worksheet.Range["D1:E1"].Merge();

    //Enter text to the cell D1 and apply formatting.
    worksheet.Range["D1"].Text = "INVOICE";
    worksheet.Range["D1"].CellStyle.Font.Bold = true;
    worksheet.Range["D1"].CellStyle.Font.RGBColor = Color.FromArgb(42, 118, 189);
    worksheet.Range["D1"].CellStyle.Font.Size = 35;

    //Apply alignment in the cell D1
    worksheet.Range["D1"].CellStyle.HorizontalAlignment = ExcelHAlign.HAlignRight;
    worksheet.Range["D1"].CellStyle.VerticalAlignment = ExcelVAlign.VAlignTop;

    //Enter values to the cells from D5 to E8
    worksheet.Range["D5"].Text = "INVOICE#";
    worksheet.Range["E5"].Text = "DATE";
    worksheet.Range["D6"].Number = 1028;
    worksheet.Range["E6"].Value = "12/31/2018";
    worksheet.Range["D7"].Text = "CUSTOMER ID";
    worksheet.Range["E7"].Text = "TERMS";
    worksheet.Range["D8"].Number = 564;
    worksheet.Range["E8"].Text = "Due Upon Receipt";

    //Apply RGB backcolor to the cells from D5 to E8
    worksheet.Range["D5:E5"].CellStyle.Color = Color.FromArgb(42, 118, 189);
    worksheet.Range["D7:E7"].CellStyle.Color = Color.FromArgb(42, 118, 189);

    //Apply known colors to the text in cells D5 to E8
    worksheet.Range["D5:E5"].CellStyle.Font.Color = ExcelKnownColors.White;
    worksheet.Range["D7:E7"].CellStyle.Font.Color = ExcelKnownColors.White;

    //Make the text as bold from D5 to E8
    worksheet.Range["D5:E8"].CellStyle.Font.Bold = true;

    //Apply alignment to the cells from D5 to E8
    worksheet.Range["D5:E8"].CellStyle.HorizontalAlignment = ExcelHAlign.HAlignCenter;
    worksheet.Range["D5:E5"].CellStyle.VerticalAlignment = ExcelVAlign.VAlignCenter;
    worksheet.Range["D7:E7"].CellStyle.VerticalAlignment = ExcelVAlign.VAlignCenter;
    worksheet.Range["D6:E6"].CellStyle.VerticalAlignment = ExcelVAlign.VAlignTop;

    //Enter value and applying formatting in the cell A7
    worksheet.Range["A7"].Text = "  BILL TO";
    worksheet.Range["A7"].CellStyle.Color = Color.FromArgb(42, 118, 189);
    worksheet.Range["A7"].CellStyle.Font.Bold = true;
    worksheet.Range["A7"].CellStyle.Font.Color = ExcelKnownColors.White;

    //Apply alignment
    worksheet.Range["A7"].CellStyle.HorizontalAlignment = ExcelHAlign.HAlignLeft;
    worksheet.Range["A7"].CellStyle.VerticalAlignment = ExcelVAlign.VAlignCenter;

    //Enter values in the cells A8 to A12
    worksheet.Range["A8"].Text = "Steyn";
    worksheet.Range["A9"].Text = "Great Lakes Food Market";
    worksheet.Range["A10"].Text = "20 Whitehall Rd";
    worksheet.Range["A11"].Text = "North Muskegon,USA";
    worksheet.Range["A12"].Text = "+1 231-654-0000";

    //Create a Hyperlink for e-mail in the cell A13
    IHyperLink hyperlink = worksheet.HyperLinks.Add(worksheet.Range["A13"]);
    hyperlink.Type = ExcelHyperLinkType.Url;
    hyperlink.Address = "Steyn@greatlakes.com";
    hyperlink.ScreenTip = "Send Mail";

    //Merge column A and B from row 15 to 22
    worksheet.Range["A15:B15"].Merge();
    worksheet.Range["A16:B16"].Merge();
    worksheet.Range["A17:B17"].Merge();
    worksheet.Range["A18:B18"].Merge();
    worksheet.Range["A19:B19"].Merge();
    worksheet.Range["A20:B20"].Merge();
    worksheet.Range["A21:B21"].Merge();
    worksheet.Range["A22:B22"].Merge();

    //Enter details of products and prices
    worksheet.Range["A15"].Text = "  DESCRIPTION";
    worksheet.Range["C15"].Text = "QTY";
    worksheet.Range["D15"].Text = "UNIT PRICE";
    worksheet.Range["E15"].Text = "AMOUNT";
    worksheet.Range["A16"].Text = "Cabrales Cheese";
    worksheet.Range["A17"].Text = "Chocos";
    worksheet.Range["A18"].Text = "Pasta";
    worksheet.Range["A19"].Text = "Cereals";
    worksheet.Range["A20"].Text = "Ice Cream";
    worksheet.Range["C16"].Number = 3;
    worksheet.Range["C17"].Number = 2;
    worksheet.Range["C18"].Number = 1;
    worksheet.Range["C19"].Number = 4;
    worksheet.Range["C20"].Number = 3;
    worksheet.Range["D16"].Number = 21;
    worksheet.Range["D17"].Number = 54;
    worksheet.Range["D18"].Number = 10;
    worksheet.Range["D19"].Number = 20;
    worksheet.Range["D20"].Number = 30;
    worksheet.Range["D23"].Text = "Total";

    //Apply number format
    worksheet.Range["D16:E22"].NumberFormat = "$.00";
    worksheet.Range["E23"].NumberFormat = "$.00";

    //Apply incremental formula for column Amount by multiplying Qty and UnitPrice
    application.EnableIncrementalFormula = true;
    worksheet.Range["E16:E20"].Formula = "=C16*D16";

    //Formula for Sum the total
    worksheet.Range["E23"].Formula = "=SUM(E16:E22)";

    //Apply borders
    worksheet.Range["A16:E22"].CellStyle.Borders[ExcelBordersIndex.EdgeTop].LineStyle = ExcelLineStyle.Thin;
    worksheet.Range["A16:E22"].CellStyle.Borders[ExcelBordersIndex.EdgeBottom].LineStyle = ExcelLineStyle.Thin;
    worksheet.Range["A16:E22"].CellStyle.Borders[ExcelBordersIndex.EdgeTop].Color = ExcelKnownColors.Grey_25_percent;
    worksheet.Range["A16:E22"].CellStyle.Borders[ExcelBordersIndex.EdgeBottom].Color = ExcelKnownColors.Grey_25_percent;
    worksheet.Range["A23:E23"].CellStyle.Borders[ExcelBordersIndex.EdgeTop].LineStyle = ExcelLineStyle.Thin;
    worksheet.Range["A23:E23"].CellStyle.Borders[ExcelBordersIndex.EdgeBottom].LineStyle = ExcelLineStyle.Thin;
    worksheet.Range["A23:E23"].CellStyle.Borders[ExcelBordersIndex.EdgeTop].Color = ExcelKnownColors.Black;
    worksheet.Range["A23:E23"].CellStyle.Borders[ExcelBordersIndex.EdgeBottom].Color = ExcelKnownColors.Black;

    //Apply font setting for cells with product details
    worksheet.Range["A3:E23"].CellStyle.Font.FontName = "Arial";
    worksheet.Range["A3:E23"].CellStyle.Font.Size = 10;
    worksheet.Range["A15:E15"].CellStyle.Font.Color = ExcelKnownColors.White;
    worksheet.Range["A15:E15"].CellStyle.Font.Bold = true;
    worksheet.Range["D23:E23"].CellStyle.Font.Bold = true;

    //Apply cell color
    worksheet.Range["A15:E15"].CellStyle.Color = Color.FromArgb(42, 118, 189);

    //Apply alignment to cells with product details
    worksheet.Range["A15"].CellStyle.HorizontalAlignment = ExcelHAlign.HAlignLeft;
    worksheet.Range["C15:C22"].CellStyle.HorizontalAlignment = ExcelHAlign.HAlignCenter;
    worksheet.Range["D15:E15"].CellStyle.HorizontalAlignment = ExcelHAlign.HAlignCenter;

    //Apply row height and column width to look good
    worksheet.Range["A1"].ColumnWidth = 36;
    worksheet.Range["B1"].ColumnWidth = 11;
    worksheet.Range["C1"].ColumnWidth = 8;
    worksheet.Range["D1:E1"].ColumnWidth = 18;
    worksheet.Range["A1"].RowHeight = 47;
    worksheet.Range["A2"].RowHeight = 15;
    worksheet.Range["A3:A4"].RowHeight = 15;
    worksheet.Range["A5"].RowHeight = 18;
    worksheet.Range["A6"].RowHeight = 29;
    worksheet.Range["A7"].RowHeight = 18;
    worksheet.Range["A8"].RowHeight = 15;
    worksheet.Range["A9:A14"].RowHeight = 15;
    worksheet.Range["A15:A23"].RowHeight = 18;

    //Saving the Excel to the MemoryStream 
    MemoryStream stream = new MemoryStream();
    workbook.SaveAs(stream);

    //Set the position as '0'
    stream.Position = 0;

    //Upload the document to Dropbox
    await UploadDocumentToDropBox(stream);

    return Ok("Excel document uploaded to DropBox Cloud Storage.");
}

// Upload file to Dropbox
public async Task<MemoryStream> UploadDocumentToDropBox(MemoryStream stream)
{
    //Define the access token for authentication
    var accessToken = "Access_Token";

    //Define the file path in Dropbox where the file should be saved. For ex: "/Template.docx"
    var filePathInDropbox = "FilePath";

    try
    {
        //Create a new DropboxClient instance using the provided access token
        using (var dbx = new DropboxClient(accessToken))
        {
            //Upload the file to Dropbox
            var uploadResult =await dbx.Files.UploadAsync(filePathInDropbox, WriteMode.Overwrite.Instance, body: new MemoryStream(stream.ToArray()));
        }
        Console.WriteLine("Upload completed successfully");
    }

    catch (Exception ex)
    {
        Console.WriteLine($"Error uploading document to DropBox: {ex.Message}");
    }
    return stream;
}

A complete working example of how to save an Excel document to Dropbox Cloud Storage in ASP.NET Core is present on this GitHub page.

By executing the program, you will get the Excel document as follows.

Output File

Click here to explore the rich set of Syncfusion® Excel library (XlsIO) features.

An online sample link to create an Excel document in ASP.NET Core.