How to read an Excel spreadsheet in c# quickly

Hi I found a very much faster way.

It is better to read the entire data in one go using "get_range". This loads the data into memory and I can loop through that like a normal array.

Microsoft.Office.Interop.Excel.Range range = gXlWs.get_Range("A1", "F188000");
object[,] values = (object[,])range.Value2;
int NumRow=1;
while (NumRow < values.GetLength(0))
{
    for (int c = 1; c <= NumCols; c++)
    {
        Fields[c - 1] = Convert.ToString(values[NumRow, c]);
    }
    NumRow++;
}

There are several options - all involve some additional library:

• OpenXML 2.0 (free library from MS) can be used to read/modify the content of an .xlsx so you can do with it what you want

• some (commercial) 3rd-party libraries come with grid controls allowing you to do much more with excel files in your application (be it Winforms/WPF/ASP.NET...) like SpreadsheetGear, Aspose.Cells etc.