С read excel spreadsheet

Opening Excel files in code has been a painful experience long before .NET Core came along. In many cases, you actually needed the Excel application installed on the target/users machine to be able to open excel files via code. If you’ve ever had to use those “OLE DB Jet ” queries before, you know it’s not a great experience. Luckily there are some pretty good open source solutions now that don’t require excel on the target machine. This is good for Windows users so that you don’t have to install excel on a target users machine or web server, but also for people hosting .NET Core applications on Linux (And even Mac/ARM) – where Excel is obviously no where to be seen!

My methodology for this article is pretty simple. Create a standardized excel workbook with a couple of sheets, couple of formulas, and a couple of special formatting cases. Read the same data out in every single library and see which one works the best for me. Simple! Let’s get going!

Note On CSV Formats

I should note that if you are reading a CSV, or more so a single excel sheet that doesn’t have formulas or anything “excel” specific on the sheet, you should instead just parse it using standard CSV technique. We have a great article here on parsing CSV in C# .NET that you should instead follow. CSV parsers are great for taking tabular data and deserializing it into objects and should be used where they can.

Example Data

I figure the best way to compare the different libraries on offer is to create a simple spreadsheet to compare the different ways we can read data out. The spreadsheet will have two “sheets”, where the second sheet references the first.

Sheet 1 is named “First Sheet” and looks like so :

Notice that cell A2 is simply the number “1”. Then in column B2, we have a reference to cell A2. This is because we want to check if the libraries allow us to not only get the “formula” from the cell, but also what the computed value should be.

We are also styling cell A2 with a font color of red, and B2 has a full border (Although hard to see as I’m trying to show the fomula). We will try and extract these styling elements out later.

Sheet 2 is named “Second Sheet” and looks like so :

So we are doing a simple “SUM” formula and referencing the first sheet. Again, this is so we can test getting both the formula and the computed value, but this time across different sheets. It’s not complicated for a person used to working with Excel, but let’s see how a few libraries handle it.

In general, in my tests I’m looking for my output to always follow the same format of :

Sheet 1 Data
Cell A2 Value   : 
Cell A2 Color   :
Cell B2 Formula :
Cell B2 Value   :
Cell B2 Border  :

Sheet 2 Data
Cell A2 Formula :
Cell A2 Value   :

That way when I show the code, you can pick the library that makes the most sense to you.

EPPlus

When I first started hunting around for parsing excel in .NET Core, I remembered using EPPlus many moons ago for some very lightweight excel parsing. The nuget package can be found here : https://www.nuget.org/packages/EPPlus/. It’s also open source so you can read through the source code if that’s your thing here : https://github.com/JanKallman/EPPlus

The code to read our excel spreadsheet looks like so :

static void Main(string[] args)
{
    using(var package = new ExcelPackage(new FileInfo("Book.xlsx")))
    {
        var firstSheet = package.Workbook.Worksheets["First Sheet"];
        Console.WriteLine("Sheet 1 Data");
        Console.WriteLine($"Cell A2 Value   : {firstSheet.Cells["A2"].Text}");
        Console.WriteLine($"Cell A2 Color   : {firstSheet.Cells["A2"].Style.Font.Color.LookupColor()}");
        Console.WriteLine($"Cell B2 Formula : {firstSheet.Cells["B2"].Formula}");
        Console.WriteLine($"Cell B2 Value   : {firstSheet.Cells["B2"].Text}");
        Console.WriteLine($"Cell B2 Border  : {firstSheet.Cells["B2"].Style.Border.Top.Style}");
        Console.WriteLine("");

        var secondSheet = package.Workbook.Worksheets["Second Sheet"];
        Console.WriteLine($"Sheet 2 Data");
        Console.WriteLine($"Cell A2 Formula : {secondSheet.Cells["A2"].Formula}");
        Console.WriteLine($"Cell A2 Value   : {secondSheet.Cells["A2"].Text}");
    }
}

Honestly what can I say. This was *super* easy and worked right out of the box. It picks up formulas vs text perfectly! The styles on our first sheet was also pretty easy to get going. The border is slightly annoying because you have to check the “Style” of the border, and if it’s a style of “None”, then it means there is no border (As opposed to a boolean for “HasBorder” or similar). But I think I’m just nit picking, EPPlus just works!

NPOI

NPOI is another open source option with a Github here : https://github.com/tonyqus/npoi and Nuget here : https://www.nuget.org/packages/NPOI/. It hasn’t had a release in over a year which isn’t that bad because it’s not like Excel itself has tonnes of updates throughout the year, but the Issues list on Github is growing a bit with a fair few bugs so keep that in mind.

The code to read our data using NPOI looks like so :

…..

…Actually you know what. I blew a bunch of time on this to try and work out the best way to use NPOI and the documentation is awful. The wiki is here : https://github.com/tonyqus/npoi/wiki/Getting-Started-with-NPOI but it has a few samples but most/all of them are about creating excel workbooks not reading them. I saw they had a link to a tutorial on how to read an Excel file which looked promising, but it was literally reading the spreadsheet and then dumping the text out.

After using EPPlus, I just didn’t see any reason to continue with this one. Almost every google answer will lead you to StackOverflow with people using NPOI with such specific use cases that it never really all pieced together for me.

ExcelDataReader

ExcelDataReader appeared in a couple of stackoverflow answers on reading excel in .NET Core. Similar to others in this list, it’s open source here : https://github.com/ExcelDataReader/ExcelDataReader and on Nuget here : https://www.nuget.org/packages/ExcelDataReader/

I wanted to make this work but…. It just doesn’t seem intuitive at all. ExcelDataReader works on the premise that you are reading “rows” and “columns” sequentially in almost a CSV fashion. That sort of works but if you are looking for a particular cell, it’s rough as hell.

Some example code :

static void Main(string[] args)
{
    System.Text.Encoding.RegisterProvider(System.Text.CodePagesEncodingProvider.Instance);
    using (var stream = File.Open("Book.xlsx", FileMode.Open, FileAccess.Read))
    {
        using (var reader = ExcelReaderFactory.CreateReader(stream))
        {
            do
            {
                while (reader.Read()) //Each ROW
                {
                    for (int column = 0; column < reader.FieldCount; column++)
                    {
                        //Console.WriteLine(reader.GetString(column));//Will blow up if the value is decimal etc. 
                        Console.WriteLine(reader.GetValue(column));//Get Value returns object
                    }
                }
            } while (reader.NextResult()); //Move to NEXT SHEET

        }
    }
}

The first line in particular is really annoying (Everything blows up without it). But you’ll notice that we are moving through row by row (And sheet by sheet) trying to get values. Ontop of that, calling things like “GetString” doesn’t work if the value is a decimal (Implicit casts would have been better IMO). I also couldn’t find any way to get the actual formula of the cell. The above only returns the computed results.

I was going to slog my way through and actually get the result we were looking for, but it’s just not a library I would use.

Syncfusion

Syncfusion is one of those annoying companies that create pay-to-use libraries, upload them to nuget, and then in small print  say you need to purchase a license or else. Personally, I would like to see Microsoft not allow paid libraries into the public Nuget repo. I’m going to include them here but their licensing starts at $995 per year, per developer, so I don’t see much reason to use it for the majority of use cases. The nuget page can be found here https://www.nuget.org/packages/Syncfusion.XlsIO.Net.Core/

The code looks like :

static void Main(string[] args)
{
    ExcelEngine excelEngine = new ExcelEngine();
    using (var stream = File.Open("Book.xlsx", FileMode.Open, FileAccess.Read))
    {
        var workbook = excelEngine.Excel.Workbooks.Open(stream);

        var firstSheet = workbook.Worksheets["First Sheet"];
        Console.WriteLine("Sheet 1 Data");
        Console.WriteLine($"Cell A2 Value   : {firstSheet.Range["A2"].DisplayText}");
        Console.WriteLine($"Cell A2 Color   : {firstSheet.Range["A2"].CellStyle.Font.RGBColor.Name}");
        Console.WriteLine($"Cell B2 Formula : {firstSheet.Range["B2"].Formula}");
        Console.WriteLine($"Cell B2 Value   : {firstSheet.Range["B2"].DisplayText}");
        Console.WriteLine($"Cell B2 Border  : {firstSheet.Range["B2"].CellStyle.Borders.Value}");
        Console.WriteLine("");

        var secondSheet = workbook.Worksheets["Second Sheet"];
        Console.WriteLine($"Sheet 2 Data");
        Console.WriteLine($"Cell A2 Formula : {secondSheet.Range["A2"].Formula}");
        Console.WriteLine($"Cell A2 Value   : {secondSheet.Range["A2"].DisplayText}");
    }
}

So not bad. I have to admit, I fiddled around trying to understand how it worked out borders (As the above code doesn’t work), but gave up. The font color also took some fiddling where the library returns non standard objects as the color. Some of the properties for the actual data are also a bit confusing where you have value, text, displaytext etc. All returning slightly different things so you sort of have to just spray and pray and see which one works.

If EPPlus didn’t exist, and Syncfusion wasn’t fantastically overpriced, this library would actually be pretty good.

TL;DR;

Use EPPlus. https://github.com/JanKallman/EPPlus

All programmers need to learn how to read excel files. This is the information age, and many people store their data in excel files because they are user-friendly. Programmers must also know all about reading excel files in their respective programming language.

If you are a .Net Programmer and struggling with reading excel files, then don’t worry — you are in the right place. I will show you a step-by-step for reading excel files using C#.

You might be thinking that reading excel files would be difficult and require high-level expertise, but this is not the case. I will show you that it only takes 2-3 lines of code with IronXL to be able to read excel files.

We will be covering the following topics in this article:

1. Introduction to IronXL
2. Creating an Example Project for our Demonstration

3. Adding IronXL Nuget Package to our Project

   a. Installing IronXL using the Package Manager Console
   b. Installing IronXL using the Manage Package Manager
   c. Directly download it and add a reference to the project

4. Read the Excel file in C#

   a. Designing the Form
   b. Code to Read the data from Excel
   c. Code to Read data within a specific range
   d. Code to Read XLs and XLSX File
   e. Code to Read CSV files

5. Summary

Introduction to IronXL:

IronXL is a .Net Library development brought to you by Iron Software. This library provides excellent functions and APIs to help us read, create and update/edit our excel files and spreadsheets. IronXL does not require Excel to be installed on your server or Interop. Moreover, IronXL provides a faster and more intuitive API than Microsoft Office Interop Excel.

IronXL works on .Net Core 2, Framework 4.5, Azure, Mono and, Mobile and Xamarin.

Creating an Example Project for our Demonstration

I will be using Windows Form App as an example, but you can use one of your choice, such as Asp.Net Web App, .Net core MVC or .Net Core web api.

To create a new project, open Visual Studio, click on «Create New Project» => Select Template; I am using the Windows Form App, you can use any of your choosing. => Click on Next Button => Name Your Project; I have named mine as «C Sharp Read Excel File». => Click on Next = > Select your Target Framework; I am selecting .Net core 3.1, but again, you can choose your own. => Finally, click on «Create Project», and a project will be created and opened for you as shown below:

Our next task is to Install the Nuget Package for IronXL.

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Adding the IronXL Nuget Package

We can add the IronXL Package in one of any three ways, so you can choose the method that suits you best.

Installing IronXL using the Package Manager Console

Open the Package Manager console in your Project and use the following command:

Go to Tools => NuGet Package Manager => Package Manager Console.

This will open the Package Manager console for you. Next, write the following command in the Package Manager console:

PM > Install-Package IronXL.Excel

Installing IronXL using the Nuget Package Manager

This is another way to install the Nuget Package Manager. If you have already completed installation using the previous method, than you won’t need to use this one.

Go to: Tools = > NuGet Package Manager => Manage NuGet Packages for Solution, and click on it.

This will open the Nuget-Solution for you; click on «Browse» and search for IronXL.Excel in the search bar:

Click on the «Install» button and it will install IronXL for you. After installing IronXL, go to your form and start designing it.

Downloading IronXL

Another way of using IronXL is to download it directly from this link. Once downloaded, just add the reference of the file in your project and start using it.

Design the Form

Now, we have to design the form to suit our requirements. I will use the minimum design for the demonstration. You can use any design depending on your needs.

Go to the ToolBox=> Select Label (for name our example app), and select the «Panel and Data» grid view. Put the «Data» grid view inside the panel. Our design will look like the following:

Our form has now been designed. Our next task is to actually write the code for reading an excel file or excel sheet in C#.

Write Code for Reading Excel Files in C

We want our app to read any given excel file at the click of a button, so for this, double-click on the «Read Excel File» button, and the following code will appear:

private void button1_Click(object sender, EventArgs e)
        {
        }

Next, add the following namespace in this file:

using System;
using System.Windows.Forms;
using IronXL;
using System.Data;

Using the IronXL namespace is necessary to access the IronXL functions. However, you can use other namespaces as per the requirements of your own projects.

WorkBook workbook = WorkBook.Load("Weather.xlsx");
            WorkSheet sheet = workbook.GetWorkSheet("Sheet1");
            DataTable dt = sheet.ToDataTable(true);
            dataGridView1.DataSource = dt;

The first statement will load the excel workbook «Weather.xlsx» for us. I have chosen the xlsx file format as an example. You can choose any file of your choice.

After loading the excel workbook, we need to select the excel worksheet we want to read. After that, we need to convert our worksheet into a data table so that we can further load it into our Data Grid View.

This will read the file for us and display all its data in the data grid view.

Output for Reading the Data from Excel File using C#:

Let’s open our «Weather.xlsx» file in Microsoft Excel and compare our output. xlsx file is the extension for a Microsoft Excel file.

Excel File:

Now that we can read excel files using C#, let’s explore some advanced options.

Let’s suppose that you want to read the data from an excel file for a specific cell range. Let’s look at how to do that.

Read Data from Excel within a Specific Cell Range:

To read the data in a specific cell range, write the following code behind the button:

WorkBook workbook = WorkBook.Load("Weather.xlsx");
            WorkSheet sheet = workbook.GetWorkSheet("Sheet1");
            var range = sheet["A1:C6"];
            DataTable dt = range.ToDataTable(true);
            dataGridView1.DataSource = dt;

The first two lines are the same as those for loading the workbook and selecting the worksheet we want to read. On the third line, we have selected the cell range within which we want to read the data. I have selected the range A1:C6 which means that it will read the first three columns: Column A, Column B, and Column C, as well as the first six rows, as shown below.

Output for Read Data within a Specific Cell Range:

Read XLS or XLSX File:

We can read excel files no matter whether the file format is xls or xlsx. In the previous example, we looked at the example of reading the data from an Xslx file. Next, let’s look at saving the same file in .xls format and then reading it. The code will remain the same, we just have to change the file name to «Wather.xls» as shown below:

WorkBook workbook = WorkBook.Load("Weather.xls");

Output for Reading XLS File:

Read CSV File in C#:

If you have csv files instead of an excel file, you have to make slight changes to the code.
Let’s look at the following example.
I have the same Weather file saved as «Weather.csv», so I am using the same file for all the examples. Again, you can use any example according to your requirements.

WorkBook workbook = WorkBook.LoadCSV("Weather.csv", fileFormat: ExcelFileFormat.XLSX, ListDelimiter: ",");
            WorkSheet sheet = workbook.DefaultWorkSheet;
            DataTable dt = sheet.ToDataTable(true);
            dataGridView1.DataSource = dt;

On the first line will load the csv file for you and define the file format. The second line will select the worksheet, while the other two code lines are the same as those in the previous examples.

Output for Reading CSV File

Summary:

In this tutorial we have learned how to read data using excel in C# by selecting specific cells and ranges, or different file formats. This all was done with just a few lines of code.

If you want to learn more about Iron Software products, please click on this link. If you decide that you’d like to try it out for yourself, then go ahead and take advantage of the Iron Software 30-day Free-Trial . You may also want to take a look at the Iron Suite, this complete package includes five .Net Libraries, this special offer means you can get all five products for the price of only two. For more information, please click here.

I hope that you have found this guide helpful and easy to follow. If you need any further assistance, please feel free to post a comment.