Read an Excel spreadsheet in memory

Question

How can I read an Excel spreadsheet that was just posted to my server? I searched for something but I only found how to read an Excel spreadsheet with the file name path which is not my case.

I need something like that:

public ActionResult Import(HttpPostedFileBase file)
{
     var excel = new ExcelQueryFactory(file); //using linq to excel
}

Answer 1

I was running into your same issue but I didn't want to switch to a paid service so this is what I did.

public class DataImportHelper : IDisposable
{
    private readonly string _fileName;
    private readonly string _tempFilePath;

    public DataImportHelper(HttpPostedFileBase file, string tempFilePath)
    {
        _fileName = file.FileName;
        _tempFilePath = Path.Combine(tempFilePath, _fileName);
        (new FileInfo(_tempFilePath)).Directory.Create();
        file.SaveAs(_tempFilePath);
    }

    public IQueryable<T> All<T>(string sheetName = "")
    {
        if (string.IsNullOrEmpty(sheetName))
        {
            sheetName = (typeof (T)).Name;
        }

        var excelSheet = new ExcelQueryFactory(_tempFilePath);

        return from t in excelSheet.Worksheet<T>(sheetName)
               select t;
    }

    public void Dispose()
    {
        File.Delete(_tempFilePath);
    }

}

Here is a Test

[Fact]
    public void AcceptsAMemoryStream()
    {
        MemoryFile file;

        using (var f = File.OpenRead("SampleData.xlsx"))
        {
            file = new MemoryFile(f, "multipart/form-data", "SampleData.xlsx");

            using (var importer = new DataImportHelper(file, "Temp/"))
            {
                var products = importer.All<Product>();

                Assert.NotEmpty(products);

            }
        }
    }

Here is MemoryFile.cs. This file is only used for testing. It is just an implementation of HttpPostedFileBase so you can test your controllers and my little helper. This was borrowed from another post.

 public class MemoryFile : HttpPostedFileBase
    {
        Stream stream;
        string contentType;
        string fileName;

        public MemoryFile(Stream stream, string contentType, string fileName)
        {
            this.stream = stream;
            this.contentType = contentType;
            this.fileName = fileName;
        }

        public override int ContentLength
        {
            get { return (int)stream.Length; }
        }

        public override string ContentType
        {
            get { return contentType; }
        }

        public override string FileName
        {
            get { return fileName; }
        }

        public override Stream InputStream
        {
            get { return stream; }
        }

        public override void SaveAs(string filename)
        {
            using (var file = File.Open(filename, FileMode.Create))
                stream.CopyTo(file);
        }
    }

Answer 2

Unfortunately it's not possible to read a spreadsheet from a stream with LinqToExcel.

That's because it uses OLEDB to read from the spreadsheets and it can't read from a stream.

Answer 3

You can use the InputStream property of HttpPostedFileBase to read the excel spreadsheet in memory.

I use ClosedXML nuget package to read excel content from stream which is available in your case. It has a simple overload which takes stream pointing to stream for the excel file (aka workbook).

imported namespaces at the top of the code file:

using ClosedXML.Excel;

Source code:

public ActionResult Import(HttpPostedFileBase file)
{
    //HttpPostedFileBase directly is of no use so commented your code
    //var excel = new ExcelQueryFactory(file); //using linq to excel
    var stream = file.InputStream;
    if (stream.Length != 0)
    {
        //handle the stream here
        using (XLWorkbook excelWorkbook = new XLWorkbook(stream))
        {
            var name = excelWorkbook.Worksheet(1).Name;
            //do more things whatever you like as you now have a handle to the entire workbook.
            var firstRow = excelWorkbook.Worksheet(1).Row(1);
        }
    }
}

Answer 4

You need Office Interops assemblies. Check the Excel Object Model for reference.