How to Read Excel Files in C# (Developer Tutorial)

using IronXL;
using System;
using System.Linq;

// Supported spreadsheet formats for reading include: XLSX, XLS, CSV and TSV
WorkBook workBook = WorkBook.Load("test.xlsx");
WorkSheet workSheet = workBook.WorkSheets.First();

// Select cells easily in Excel notation and return the calculated value
int cellValue = workSheet["A2"].IntValue;

// Read from Ranges of cells elegantly.
foreach (var cell in workSheet["A2:A10"])
{
    Console.WriteLine("Cell {0} has value '{1}'", cell.AddressString, cell.Text);
}

// Advanced Operations
// Calculate aggregate values such as Min, Max and Sum
decimal sum = workSheet["A2:A10"].Sum();

// Linq compatible
decimal max = workSheet["A2:A10"].Max(c => c.DecimalValue);

Imports IronXL
Imports System
Imports System.Linq

' Supported spreadsheet formats for reading include: XLSX, XLS, CSV and TSV
Private workBook As WorkBook = WorkBook.Load("test.xlsx")
Private workSheet As WorkSheet = workBook.WorkSheets.First()

' Select cells easily in Excel notation and return the calculated value
Private cellValue As Integer = workSheet("A2").IntValue

' Read from Ranges of cells elegantly.
For Each cell In workSheet("A2:A10")
	Console.WriteLine("Cell {0} has value '{1}'", cell.AddressString, cell.Text)
Next cell

' Advanced Operations
' Calculate aggregate values such as Min, Max and Sum
Dim sum As Decimal = workSheet("A2:A10").Sum()

' Linq compatible
Dim max As Decimal = workSheet("A2:A10").Max(Function(c) c.DecimalValue)

WorkBook workBook = WorkBook.Load(@"Spreadsheets\\GDP.xlsx");

Dim workBook As WorkBook = WorkBook.Load("Spreadsheets\\GDP.xlsx")

WorkBook workBook = new WorkBook(ExcelFileFormat.XLSX);

Dim workBook As New WorkBook(ExcelFileFormat.XLSX)

WorkSheet workSheet = workBook.GetWorkSheet("GDPByCountry");

Dim workSheet As WorkSheet = workBook.GetWorkSheet("GDPByCountry")

WorkBook workBook = WorkBook.Load("test.xlsx");
WorkSheet workSheet = workBook.DefaultWorkSheet;
IronXL.Cell cell = workSheet["B1"].First();

Dim workBook As WorkBook = WorkBook.Load("test.xlsx")
Dim workSheet As WorkSheet = workBook.DefaultWorkSheet
Dim cell As IronXL.Cell = workSheet("B1").First()

IronXL.Cell cell = workSheet["B1"].First();
string value = cell.StringValue;   // Read the value of the cell as a string
Console.WriteLine(value);

cell.Value = "10.3289";           // Write a new value to the cell
Console.WriteLine(cell.StringValue);

Dim cell As IronXL.Cell = workSheet("B1").First()
Dim value As String = cell.StringValue ' Read the value of the cell as a string
Console.WriteLine(value)

cell.Value = "10.3289" ' Write a new value to the cell
Console.WriteLine(cell.StringValue)

Range range = workSheet["D2:D101"];

Dim range As Range = workSheet("D2:D101")

// Iterate through the rows
for (var y = 2; y <= 101; y++)
{
    var result = new PersonValidationResult { Row = y };
    results.Add(result);

    // Get all cells for the person
    var cells = workSheet[$"A{y}:E{y}"].ToList();

    // Validate the phone number (1 = B)
    var phoneNumber = cells[1].Value;
    result.PhoneNumberErrorMessage = ValidatePhoneNumber(phoneNumberUtil, (string)phoneNumber);

    // Validate the email address (3 = D)
    result.EmailErrorMessage = ValidateEmailAddress((string)cells[3].Value);

    // Get the raw date in the format of Month Day[suffix], Year (4 = E)
    var rawDate = (string)cells[4].Value;
    result.DateErrorMessage = ValidateDate(rawDate);
}

' Iterate through the rows
For y = 2 To 101
	Dim result = New PersonValidationResult With {.Row = y}
	results.Add(result)

	' Get all cells for the person
	Dim cells = workSheet($"A{y}:E{y}").ToList()

	' Validate the phone number (1 = B)
	Dim phoneNumber = cells(1).Value
	result.PhoneNumberErrorMessage = ValidatePhoneNumber(phoneNumberUtil, CStr(phoneNumber))

	' Validate the email address (3 = D)
	result.EmailErrorMessage = ValidateEmailAddress(CStr(cells(3).Value))

	' Get the raw date in the format of Month Day[suffix], Year (4 = E)
	Dim rawDate = CStr(cells(4).Value)
	result.DateErrorMessage = ValidateDate(rawDate)
Next y

// Iterate through all rows with a value
for (var y = 2 ; y < i ; y++)
{
    // Get the C cell
    Cell cell = workSheet[$"C{y}"].First();

    // Set the formula for the Percentage of Total column
    cell.Formula = $"=B{y}/B{i}";
}

' Iterate through all rows with a value
Dim y = 2
Do While y < i
	' Get the C cell
	Dim cell As Cell = workSheet($"C{y}").First()

	' Set the formula for the Percentage of Total column
	cell.Formula = $"=B{y}/B{i}"
	y += 1
Loop

// Iterate through the rows
for (var i = 2; i <= 101; i++)
{
    var result = new PersonValidationResult { Row = i };
    results.Add(result);

    // Get all cells for the person
    var cells = worksheet[$"A{i}:E{i}"].ToList();

    // Validate the phone number (1 = B)
    var phoneNumber = cells[1].Value;
    result.PhoneNumberErrorMessage = ValidatePhoneNumber(phoneNumberUtil, (string)phoneNumber);

    // Validate the email address (3 = D)
    result.EmailErrorMessage = ValidateEmailAddress((string)cells[3].Value);

    // Get the raw date in the format of Month Day[suffix], Year (4 = E)
    var rawDate = (string)cells[4].Value;
    result.DateErrorMessage = ValidateDate(rawDate);
}

' Iterate through the rows
For i = 2 To 101
	Dim result = New PersonValidationResult With {.Row = i}
	results.Add(result)

	' Get all cells for the person
	Dim cells = worksheet($"A{i}:E{i}").ToList()

	' Validate the phone number (1 = B)
	Dim phoneNumber = cells(1).Value
	result.PhoneNumberErrorMessage = ValidatePhoneNumber(phoneNumberUtil, CStr(phoneNumber))

	' Validate the email address (3 = D)
	result.EmailErrorMessage = ValidateEmailAddress(CStr(cells(3).Value))

	' Get the raw date in the format of Month Day[suffix], Year (4 = E)
	Dim rawDate = CStr(cells(4).Value)
	result.DateErrorMessage = ValidateDate(rawDate)
Next i

var resultsSheet = workBook.CreateWorkSheet("Results");
resultsSheet["A1"].Value = "Row";
resultsSheet["B1"].Value = "Valid";
resultsSheet["C1"].Value = "Phone Error";
resultsSheet["D1"].Value = "Email Error";
resultsSheet["E1"].Value = "Date Error";
for (var i = 0; i < results.Count; i++)
{
    var result = results[i];
    resultsSheet[$"A{i + 2}"].Value = result.Row;
    resultsSheet[$"B{i + 2}"].Value = result.IsValid ? "Yes" : "No";
    resultsSheet[$"C{i + 2}"].Value = result.PhoneNumberErrorMessage;
    resultsSheet[$"D{i + 2}"].Value = result.EmailErrorMessage;
    resultsSheet[$"E{i + 2}"].Value = result.DateErrorMessage;
}
workBook.SaveAs(@"Spreadsheets\\PeopleValidated.xlsx");

Dim resultsSheet = workBook.CreateWorkSheet("Results")
resultsSheet("A1").Value = "Row"
resultsSheet("B1").Value = "Valid"
resultsSheet("C1").Value = "Phone Error"
resultsSheet("D1").Value = "Email Error"
resultsSheet("E1").Value = "Date Error"
For i = 0 To results.Count - 1
	Dim result = results(i)
	resultsSheet($"A{i + 2}").Value = result.Row
	resultsSheet($"B{i + 2}").Value = If(result.IsValid, "Yes", "No")
	resultsSheet($"C{i + 2}").Value = result.PhoneNumberErrorMessage
	resultsSheet($"D{i + 2}").Value = result.EmailErrorMessage
	resultsSheet($"E{i + 2}").Value = result.DateErrorMessage
Next i
workBook.SaveAs("Spreadsheets\\PeopleValidated.xlsx")

public class Country
    {
        [Key]
        public Guid Key { get; set; }
        public string Name { get; set; }
        public decimal GDP { get; set; }
    }

Public Class Country
		<Key>
		Public Property Key() As Guid
		Public Property Name() As String
		Public Property GDP() As Decimal
End Class

public class CountryContext : DbContext
    {
        public DbSet<Country> Countries { get; set; }
        public CountryContext()
        {
            //TODO: Make async
            Database.EnsureCreated();
        }
        /// <summary>
        /// Configure context to use Sqlite
        /// </summary>
        /// <param name="optionsBuilder"></param>
        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            var connection = new SqliteConnection($"Data Source=Country.db");
            connection.Open();
            var command = connection.CreateCommand();
            //Create the database if it doesn't already exist
            command.CommandText = $"PRAGMA foreign_keys = ON;";
            command.ExecuteNonQuery();
            optionsBuilder.UseSqlite(connection);
            base.OnConfiguring(optionsBuilder);
        }
    }

Public Class CountryContext
	Inherits DbContext

		Public Property Countries() As DbSet(Of Country)
		Public Sub New()
			'TODO: Make async
			Database.EnsureCreated()
		End Sub
		''' <summary>
		''' Configure context to use Sqlite
		''' </summary>
		''' <param name="optionsBuilder"></param>
		Protected Overrides Sub OnConfiguring(ByVal optionsBuilder As DbContextOptionsBuilder)
			Dim connection = New SqliteConnection($"Data Source=Country.db")
			connection.Open()
			Dim command = connection.CreateCommand()
			'Create the database if it doesn't already exist
			command.CommandText = $"PRAGMA foreign_keys = ON;"
			command.ExecuteNonQuery()
			optionsBuilder.UseSqlite(connection)
			MyBase.OnConfiguring(optionsBuilder)
		End Sub
End Class

public async Task ProcessAsync()
{
    //Get the first worksheet
    var workbook = WorkBook.Load(@"Spreadsheets\\GDP.xlsx");
    var worksheet = workbook.GetWorkSheet("GDPByCountry");
    //Create the database connection
    using (var countryContext = new CountryContext())
    {
        //Iterate through all the cells
        for (var i = 2; i <= 213; i++)
        {
            //Get the range from A-B
            var range = worksheet[$"A{i}:B{i}"].ToList();
            //Create a Country entity to be saved to the database
            var country = new Country
            {
                Name = (string)range[0].Value,
                GDP = (decimal)(double)range[1].Value
            };
            //Add the entity
            await countryContext.Countries.AddAsync(country);
        }
        //Commit changes to the database
        await countryContext.SaveChangesAsync();
    }
}

Public Async Function ProcessAsync() As Task
	'Get the first worksheet
	Dim workbook = WorkBook.Load("Spreadsheets\\GDP.xlsx")
	Dim worksheet = workbook.GetWorkSheet("GDPByCountry")
	'Create the database connection
	Using countryContext As New CountryContext()
		'Iterate through all the cells
		For i = 2 To 213
			'Get the range from A-B
			Dim range = worksheet($"A{i}:B{i}").ToList()
			'Create a Country entity to be saved to the database
			Dim country As New Country With {
				.Name = CStr(range(0).Value),
				.GDP = CDec(CDbl(range(1).Value))
			}
			'Add the entity
			Await countryContext.Countries.AddAsync(country)
		Next i
		'Commit changes to the database
		Await countryContext.SaveChangesAsync()
	End Using
End Function

var client = new Client(new Uri("https://restcountries.eu/rest/v2/"));
List<RestCountry> countries = await client.GetAsync<List<RestCountry>>();

Dim client As New Client(New Uri("https://restcountries.eu/rest/v2/"))
Dim countries As List(Of RestCountry) = Await client.GetAsync(Of List(Of RestCountry))()

for (var i = 2; i < countries.Count; i++)
{
    var country = countries[i];
    //Set the basic values
    workSheet[$"A{i}"].Value = country.name;
    workSheet[$"B{i}"].Value = country.population;
    workSheet[$"G{i}"].Value = country.region;
    workSheet[$"H{i}"].Value = country.numericCode;
    //Iterate through languages
    for (var x = 0; x < 3; x++)
    {
        if (x > (country.languages.Count - 1)) break;
        var language = country.languages[x];
        //Get the letter for the column
        var columnLetter = GetColumnLetter(4 + x);
        //Set the language name
        workSheet[$"{columnLetter}{i}"].Value = language.name;
    }
}

For i = 2 To countries.Count - 1
	Dim country = countries(i)
	'Set the basic values
	workSheet($"A{i}").Value = country.name
	workSheet($"B{i}").Value = country.population
	workSheet($"G{i}").Value = country.region
	workSheet($"H{i}").Value = country.numericCode
	'Iterate through languages
	For x = 0 To 2
		If x > (country.languages.Count - 1) Then
			Exit For
		End If
		Dim language = country.languages(x)
		'Get the letter for the column
		Dim columnLetter = GetColumnLetter(4 + x)
		'Set the language name
		workSheet($"{columnLetter}{i}").Value = language.name
	Next x
Next i