如何将C＃对象列表导出到Excel电子表格？

Question

I have a C# list that I created from an Excel spreadsheet, and I want to export it to Excel. How can I achieve that task? This is just a console project. I do not intend to display the data in a .Net application. I just need the spread sheet.

var fileName = string.Format("C:\\Users\\SGurmu\\Desktop\\Data 091510.xls");
var connectionString = string.Format("Provider=Microsoft.Jet.OLEDB.4.0; data source={0}; Extended Properties=Excel 8.0;", fileName);

var fileName2 = string.Format("C:\\Users\\SGurmu\\Desktop\\Copy of Prototype.xls");
var connectionString2 = string.Format("Provider=Microsoft.Jet.OLEDB.4.0; data source={0}; Extended Properties=Excel 8.0;", fileName);

var adapter = new OleDbDataAdapter("SELECT * FROM [Sheet1$]", connectionString);
var ds = new DataSet();

adapter.Fill(ds, "contacts");

var data = ds.Tables["contacts"].AsEnumerable();

List<EmployeeData> query = data.Where(x => x.Field<string>("First_Name") != string.Empty).Select(x =>

new EmployeeData
    {
    empID = x.Field<double>("EMPLOYEE"),
    firstName = x.Field<string>("First_Name"),
    lastName = x.Field<string>("Last_Name"),
    JobCategory = x.Field<string>("Job Title"),
    StartDate = x.Field<Nullable<DateTime>>("Hire Dt"),
    EndDate =   x.Field<Nullable<DateTime>>("Term Dt"),
    TermReason = x.Field<string>("Term Reason"),
    PeggedUID = x.Field<Nullable<double>>("Pegged UserID"),
    UpdateDate = x.Field<Nullable<DateTime>>("Last Updated")
    }).ToList();

Answer 1

1. Right-click the project and manage nuget packages.
2. Add the ClosedXML nuget package
3. Add using ClosedXML.Excel; to the top of the class file.
4. Add the 'ToExcelFile' method to your class.
5. Convert your list to a DataTable.

ToExcelFile method

public static bool ToExcelFile(this DataTable dt, string filename)
{
    bool Success = false;
    //try
    //{
        XLWorkbook wb = new XLWorkbook();

        wb.Worksheets.Add(dt, "Sheet 1");

        if (filename.Contains("."))
        {
            int IndexOfLastFullStop = filename.LastIndexOf('.');

            filename = filename.Substring(0, IndexOfLastFullStop) + ".xlsx";

        }

        filename = filename + ".xlsx";

        wb.SaveAs(filename);

        Success = true;

    //}
    //catch (Exception ex)
    //{
        //ex.HandleException();

    //}
    return Success;
}

Convert your list to a DataTable

    public static DataTable ToDataTable(List<string> list)
    {
        DataTable MethodResult = null;

        DataTable dt = new DataTable();
        dt.Columns.Add("Item", );

        foreach(string s in list)
        {
            DataRow dr = dt.NewRow();
            dr[0] = s;
            dt.Rows.Add(dr);

        }

        dt.AcceptChanges();

        MethodResult = dt;

        return MethodResult;

    }

Answer 2

maybe you could try use Infodinamica.Framework.Expotable package, hosted in Nuget.

With it, you could do something like this

List<EmployeeData> query = data.Where(x => x.Field<string>("First_Name") != string.Empty).Select(x =>

    new EmployeeData
        {
        empID = x.Field<double>("EMPLOYEE"),
        firstName = x.Field<string>("First_Name"),
        lastName = x.Field<string>("Last_Name"),
        JobCategory = x.Field<string>("Job Title"),
        StartDate = x.Field<Nullable<DateTime>>("Hire Dt"),
        EndDate =   x.Field<Nullable<DateTime>>("Term Dt"),
        TermReason = x.Field<string>("Term Reason"),
        PeggedUID = x.Field<Nullable<double>>("Pegged UserID"),
        UpdateDate = x.Field<Nullable<DateTime>>("Last Updated")
        }).ToList();

    IExportEngine engine = new ExcelExportEngine();
    engine.AddData(EmployeeData);
    MemoryStream memory = engine.Export();

You can install with nuget command:

Install-Package Infodinamica.Framework.Exportable

The only problem, documentation is in spanish.

The project page is here

Export example (in spanish) is here

It also enable import files (in spanish) here