Program to convert XLS files to CSV not creating the file when run

Question

I am building an application in Visual Studio 2019 Community edition to convert an Excel XLS file to a CSV. I had found some example code that was using the ExcelReader library and modified it so it would pull the XLS file and make a test.csv file. When I run this I do not get any errors back, but the file is not created.

This is to help automate a currently manual process where we have to manually open the XLS file and save it as a CSV. I am using Visual Studio Community edition (2019) and have added the ExcelReader library.

'''public partial class Default2 : System.Web.UI.Page
{
    static void Main() { }
    DataSet result = new DataSet();
    string filePath = 
@"C:\Users\BEM26331\Documents\AppDevProjects\9.10.19.xls";

    protected void UploadButton_Click(object sender, EventArgs e)
    {
    }

    protected void Page_Load(object sender, EventArgs e)
    {
        FileStream stream = File.Open(filePath, FileMode.Open, 
FileAccess.Read);

        Excel.IExcelDataReader excelReader = 
Excel.ExcelReaderFactory.CreateBinaryReader(stream);
        DataSet result = excelReader.AsDataSet();
        excelReader.Close();

        result.Tables[0].TableName.ToString();

        string csvData = "";
        int row_no = 0;
        int ind = 0;

        while (row_no < result.Tables[ind].Rows.Count)
        {
            for (int i = 0; i < result.Tables[ind].Columns.Count; i++)
            {
                csvData += result.Tables[ind].Rows[row_no][i].ToString() 
+ ",";
            }
            row_no++;
            csvData += "\n";
        }

        string output = 
@"C:\Users\BEM26331\Documents\AppDevProjects\test.csv";
        StreamWriter csv = new StreamWriter(@output, false);
        csv.Write(csvData);
        csv.Close();
    }
}'''

The end result should create the same file, but saved as a CSV. The actual output does not create any file.

yob · Accepted Answer · 2019-10-15 13:08:08Z

1

Something like this perhaps?:

    public void ConvertToCSV(string sourceFile, string targetFile)
            {
                using (var stream = System.IO.File.Open(sourceFile, System.IO.FileMode.Open, System.IO.FileAccess.Read))
                {
                    //add ExcelDataReader and ExcelDataReader.DataSet
                    //Reading from a OpenXml Excel file (2007 format; *.xlsx)
                    using (var reader = ExcelDataReader.ExcelReaderFactory.CreateOpenXmlReader(stream))
                    {
                        //DataSet result = reader.AsDataSet();
                        DataSet result = reader.AsDataSet(new ExcelDataSetConfiguration()
                        {
                            ConfigureDataTable = (_) => new ExcelDataTableConfiguration() { UseHeaderRow = true }
                        });
                        if (result.Tables.Count > 0)
                        {
                                System.Text.StringBuilder output = new StringBuilder();
                            DataTable table = result.Tables[0];
                            //save column names
                            output.AppendLine(String.Join(",", table.Columns.Cast<System.Data.DataColumn>().ToList()));
                            //save all rows
                            foreach (System.Data.DataRow dr in table.Rows)
                            {
                                output.AppendLine(String.Join(",", dr.ItemArray.Select(f=>f.ToString() ).ToList()   ) );
                            }
                            System.IO.File.WriteAllText(targetFile, output.ToString());
                        }
                    }
                }
            }

answered Oct 15, 2019 at 13:08

yob

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10 Comments

htmlbran86 Over a year ago

Thanks! I will test this and let you know.

htmlbran86 Over a year ago

Sorry, do you recommend using this in place of the code I had posted, or would this be added to it?

yob Over a year ago

@htmlbran86 - is it working for you as expected? then, yes, you can just re-use it.

htmlbran86 Over a year ago

I'm still having issues with this. I've tried using both sets of code, then just yours and getting errors. I do appreciate the help. I'll be able to look at this more tonight.

yob Over a year ago

@htmlbran86 - what are the errors?, what are you using - webforms, winforms?

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