Merge or combine multiple Excel files in C#, VB.NET
Syncfusion Excel (XlsIO) library is a .NET Excel library used to create, read, and edit Excel documents. Using this library, you can split one Excel file into multiple files or combine several Excel files into a single file in C# and VB.NET.
Steps to merge or combine multiple Excel files into a single Excel file programmatically:
Step 1: Create a new C# console application project.
Create a new C# console application
Step 2: Install Syncfusion.XlsIO.WinForms NuGet package as a reference to your .NET Framework applications from the NuGet.org.
Install NuGet package
Step 3: Include the following namespaces in the Program.cs file.
C#
using Syncfusion.XlsIO; using System.IO; using System.Reflection;
VB.NET
Imports Syncfusion.XlsIO Imports System.IO Imports System.Reflection
Step 4: Add the following code snippet to merge or combine multiple Excel files into single Excel file.
C#
//Initialize ExcelEngine
using (ExcelEngine excelEngine = new ExcelEngine())
{
//Initialize Application
IApplication application = excelEngine.Excel;
//Set default application version
application.DefaultVersion = ExcelVersion.Excel2013;
//Open existing workbooks with data entered
Assembly assembly = typeof(Program).GetTypeInfo().Assembly;
Stream fileStream1 = assembly.GetManifestResourceStream("MergeExcelFiles.Owner.xlsx");
IWorkbook workbook1 = application.Workbooks.Open(fileStream1);
IWorksheet worksheet = workbook1.Worksheets[0];
Stream fileStream2 = assembly.GetManifestResourceStream("MergeExcelFiles.Sales Manager.xlsx");
IWorkbook workbook2 = application.Workbooks.Open(fileStream2);
Stream fileStream3 = assembly.GetManifestResourceStream("MergeExcelFiles.Sales Representative.xlsx");
IWorkbook workbook3 = application.Workbooks.Open(fileStream3);
//The content in the range A1:C8 from workbook2 and workbook3 is copied to workbook1
int lastRow = worksheet.UsedRange.LastRow;
workbook2.Worksheets[0].UsedRange.CopyTo(worksheet.Range[lastRow + 1, 1]);
lastRow = worksheet.UsedRange.LastRow;
workbook3.Worksheets[0].UsedRange.CopyTo(worksheet.Range[lastRow + 1, 1]);
worksheet.UsedRange.AutofitColumns();
//Save the workbook
workbook1.SaveAs("Output.xlsx");
}
VB.NET
'Initialize ExcelEngine
Using excelEngine As ExcelEngine = New ExcelEngine()
'Initialize Application
Dim application As IApplication = excelEngine.Excel
'Set default application version
application.DefaultVersion = ExcelVersion.Excel2013
'Open existing workbooks with data entered
Dim assembly As Assembly = GetType(Program).GetTypeInfo.Assembly
Dim fileStream1 As Stream = assembly.GetManifestResourceStream("MergeExcelFiles.Owner.xlsx")
Dim workbook1 As IWorkbook = application.Workbooks.Open(fileStream1)
Dim worksheet As IWorksheet = workbook1.Worksheets(0)
Dim fileStream2 As Stream = assembly.GetManifestResourceStream("MergeExcelFiles.Sales Manager.xlsx")
Dim workbook2 As IWorkbook = application.Workbooks.Open(fileStream2)
Dim fileStream3 As Stream = assembly.GetManifestResourceStream("MergeExcelFiles.Sales Representative.xlsx")
Dim workbook3 As IWorkbook = application.Workbooks.Open(fileStream3)
'The content in the range A1:C8 from workbook2 and workbook3 is copied to workbook1
Dim lastRow As Integer = worksheet.UsedRange.LastRow
workbook2.Worksheets(0).UsedRange.CopyTo(worksheet.Range((lastRow + 1), 1))
lastRow = worksheet.UsedRange.LastRow
workbook3.Worksheets(0).UsedRange.CopyTo(worksheet.Range((lastRow + 1), 1))
worksheet.UsedRange.AutofitColumns()
'Save the workbook
workbook1.SaveAs("Output.xlsx")
End Using
A complete working example to merge or combine multiple Excel files along with the input files used can be downloaded from Merge Excel files.zip.
CopyTo() method copies the range to the specified destination range. CopyTo() method has four overloads to merge or combine multiple Excel files whose API references are as follows:
- CopyTo(IRange)
- CopyTo(IRange,ExcelCopyRangeOptions)
- CopyTo(IRange,Boolean)
- CopyTo(IRange,ExcelCopyRangeOptions,Boolean)
The input files used in this sample looks like,
Input file
By executing the program, you will get the output Excel file as shown below.
Output Excel document
Take a moment to peruse the documentation, where you can find basic worksheet data manipulation options along with features like Conditional Formatting, worksheet calculations through Formulas, adding Charts in worksheet or workbook, organizing and analyzing data through Tables and Pivot Tables, appending multiple records to worksheet using Template Markers, and most importantly PDF and Image conversions with code examples.
Refer here to explore the rich set of Syncfusion Excel (XlsIO) library features.
See Also:
Split single Excel file into multiple Excel files
Starting with v16.2.0.x, if you reference Syncfusion assemblies from trial setup or from the NuGet feed, include a license key in your projects. Refer the link to learn about generating and registering Syncfusion license key in your application to use the components without trail message.
