Create, read, and edit Excel files in UWP

22 Dec 202224 minutes to read

Syncfusion Excel library for UWP platform can be used to create, read, edit Excel files. This also convert Excel files to PDF.

Create a simple Excel report

The below steps illustrates creating an simple Invoice formatted Excel document in UWP application.

  1. Create a new C# Blank App (Universal Windows) project.

Create UWP application in Visual Studio

  1. Install the Syncfusion.XlsIO.UWP NuGet package as reference to your .NET Framework applications from NuGet.org.

Add XlsIO reference to the project

  1. Add a new button in the MainPage.xaml as shown below.

    <Page
        x:Class="GettingStarted_UWP.MainPage"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="using:GettingStarted_UWP"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        mc:Ignorable="d"
        Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
       
        <Grid>
            <Button x:Name="button" Content="Create Document" Click="OnButtonClicked" HorizontalAlignment="Center" VerticalAlignment="Center"/>
        </Grid>
    </Page>
  2. Include the following namespaces in the MainPage.xaml.cs file.

    using Syncfusion.XlsIO;
    using Windows.Storage.Pickers;
    using Windows.Storage;
    using Windows.UI;
    Imports Syncfusion.XlsIO
    Imports Windows.Storage.Pickers
    Imports Windows.Storage
    Imports Windows.UI
  3. Include the below code snippet in the click event of the button in MainPage.xaml.cs, to create an Excel file and save the Excel document as a physical file and open the file for viewing.

    //Create an instance of ExcelEngine.
    using (ExcelEngine excelEngine = new ExcelEngine())
    {
      IApplication application = excelEngine.Excel;
      application.DefaultVersion = ExcelVersion.Xlsx;
       
      //Create a workbook with a worksheet
      IWorkbook workbook = application.Workbooks.Create(1);
       
      //Access first worksheet from the workbook instance.
      IWorksheet worksheet = workbook.Worksheets[0];
      Assembly executingAssembly = typeof(MainPage).GetTypeInfo().Assembly;
      Stream inputStream = executingAssembly.GetManifestResourceStream("GettingStarted_UWP.AdventureCycles-Logo.png");
       
      //Add a picture
      IPictureShape shape = worksheet.Pictures.AddPicture(1, 1, inputStream, 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 = ColorHelper.FromArgb(0, 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 = ColorHelper.FromArgb(0, 42, 118, 189);
      worksheet.Range["D7:E7"].CellStyle.Color = ColorHelper.FromArgb(0, 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 = ColorHelper.FromArgb(0, 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";
       
      //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";
       
      //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();
       
      //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 = ColorHelper.FromArgb(0, 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;
       
      // Save the Workbook
      StorageFile storageFile;
      if (!(Windows.Foundation.Metadata.ApiInformation.IsTypePresent("Windows.Phone.UI.Input.HardwareButtons")))
      {
        FileSavePicker savePicker = new FileSavePicker();
        savePicker.SuggestedStartLocation = PickerLocationId.Desktop;
        savePicker.SuggestedFileName = "Output";
        savePicker.FileTypeChoices.Add("Excel Files", new List<string>() { ".xlsx" });
        storageFile = await savePicker.PickSaveFileAsync();
      }
      else
      {
        StorageFolder local = Windows.Storage.ApplicationData.Current.LocalFolder;
        storageFile = await local.CreateFileAsync("Output.xlsx", CreationCollisionOption.ReplaceExisting);
      }
      //Saving the workbook
      await workbook.SaveAsAsync(storageFile);
       
      // Launch the saved file
      await Windows.System.Launcher.LaunchFileAsync(storageFile);
    }
    Private Sub OnButtonClicked(ByVal sender As Object, ByVal args As EventArgs)
    'Create an instance of ExcelEngine
    Using excelEngine As ExcelEngine = New ExcelEngine()
      Dim application As IApplication = excelEngine.Excel
      application.DefaultVersion = ExcelVersion.Xlsx
       
      'Create a workbook
      Dim workbook As IWorkbook = application.Workbooks.Create(1)
      Dim worksheet As IWorksheet = workbook.Worksheets(0)
       
      'Adding a picture
      Dim executingAssembly As Assembly = GetType(MainPage).GetTypeInfo().Assembly
      Dim inputStream As Stream = executingAssembly.GetManifestResourceStream("GettingStarted_UWP.AdventureCycles-Logo.png")
      Dim shape As IPictureShape = worksheet.Pictures.AddPicture(1, 1, inputStream, 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 = ColorHelper.FromArgb(0, 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 back color to the cells from D5 to E8
      worksheet.Range("D5:E5").CellStyle.Color = ColorHelper.FromArgb(0, 42, 118, 189)
      worksheet.Range("D7:E7").CellStyle.Color = ColorHelper.FromArgb(0,42, 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 = ColorHelper.FromArgb(0, 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
      Dim hyperlink As IHyperLink = 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 = ColorHelper.FromArgb(0, 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
       
      'Save the Workbook
      Dim storageFile As StorageFile
      If Not Windows.Foundation.Metadata.ApiInformation.IsTypePresent("Windows.Phone.UI.Input.HardwareButtons") Then
        Dim savePicker As FileSavePicker = New FileSavePicker
        savePicker.SuggestedStartLocation = PickerLocationId.Desktop
        savePicker.SuggestedFileName = "Output"
        savePicker.FileTypeChoices.Add("Excel Files", New List(Of String))
        storageFile = savePicker.PickSaveFileAsync
      Else
        Dim local As StorageFolder = Windows.Storage.ApplicationData.Current.LocalFolder
        storageFile = local.CreateFileAsync("Output.xlsx", CreationCollisionOption.ReplaceExisting)
      End If
       
      'Saving the workbook
      Function workbook_SaveAsAsync_((ByVal Unknown As storageFile) As await Implements workbook.SaveAsAsync.(Of
      End Function
       
      'Launch the saved file
      Function Windows_System_Launcher_LaunchFileAsync_((ByVal Unknown As storageFile) As await Implements Windows.System.Launcher.LaunchFileAsync.(Of
      End Function
    End Using

A complete working example of how to create an Excel file in UWP in C# is present on this GitHub page.

By executing the program, you will get the Excel file as below.
Output File
Output File

Read and Edit Excel file

The below code illustrates how to read and edit an Excel file in UWP.

//Create an instance of ExcelEngine
ExcelEngine excelEngine = new ExcelEngine();
IApplication application = excelEngine.Excel;

//Instantiates the File Picker. 
FileOpenPicker openPicker = new FileOpenPicker();
openPicker.SuggestedStartLocation = PickerLocationId.Desktop;
openPicker.FileTypeFilter.Add(".xlsx");
openPicker.FileTypeFilter.Add(".xls");
StorageFile openFile = await openPicker.PickSingleFileAsync();

//Opens the workbook. 
IWorkbook workbook = await application.Workbooks.OpenAsync(openFile);

//Access first worksheet from the workbook.
IWorksheet worksheet = workbook.Worksheets[0];

//Set Text in cell A3.
worksheet.Range["A3"].Text ="Hello World";

//Access a cell value from Excel
var value = worksheet.Range["A1"].Value;

//Sets workbook version.
workbook.Version = ExcelVersion.Xlsx;

//Initializes FileSavePicker.
FileSavePicker savePicker = new FileSavePicker();
savePicker.SuggestedStartLocation = PickerLocationId.Desktop;
savePicker.SuggestedFileName = "CreateSpreadsheet";
savePicker.FileTypeChoices.Add("Excel Files", new List<string>() { ".xlsx" });

//Creates a storage file from FileSavePicker.
StorageFile storageFile = await savePicker.PickSaveFileAsync();

//Saves changes to the specified storage file.
await workbook.SaveAsAsync(storageFile);

workbook.Close();
excelEngine.Dispose();
'Create an instance of ExcelEngine
Dim excelEngine As ExcelEngine = New ExcelEngine()
Dim application As IApplication = excelEngine.Excel

'Instantiates the File Save Picker.  
Dim openPicker As New FileOpenPicker()
openPicker.SuggestedStartLocation = PickerLocationId.Desktop 
openPicker.FileTypeFilter.Add(".xlsx") 
openPicker.FileTypeFilter.Add(".xls") 
Dim openFile As StorageFile = Await openPicker.PickSingleFileAsync()

'Opens the Workbook. 
Dim workbook As IWorkbook = Await application.Workbooks.OpenAsync(openFile)
Dim workbook.SaveAsAsyncCType(As await, openFile)

'Access first worksheet from the workbook.
Dim worksheet As IWorksheet = workbook.Worksheets(0)

'Set Text in cell A3.
worksheet.Range("A3").Text ="Hello World"

'Access a cell value from Excel
Dim value As var = worksheet.Range("A1").Value

'Sets workbook version.
workbook.Version = ExcelVersion.Xlsx

'Initializes FileSavePicker.
Dim savePicker As New FileSavePicker()
savePicker.SuggestedStartLocation = PickerLocationId.Desktop
savePicker.SuggestedFileName = "CreateSpreadsheet"
savePicker.FileTypeChoices.Add("Excel Files", New List(Of String)() From {".xlsx"})

'Creates a storage file from FileSavePicker.
Dim storageFile As StorageFile = Await savePicker.PickSaveFileAsync()

'Saves changes to the specified storage file.
Await workbook.SaveAsAsync(storageFile)

workbook.Close()
excelEngine.Dispose()

A complete working example of how to read and edit an Excel file in UWP in C# is present on this GitHub page.

NOTE

Starting with v16.2.0.x, if you reference Syncfusion assemblies from trial setup or from the NuGet feed, you also have to add “Syncfusion.Licensing” assembly reference and include a license key in your projects. Please refer to this link to know about registering Syncfusion license key in your applications to use our components. You can also explore our UWP Excel library demo that shows how to create and modify Excel files from C# with just five lines of code.