c# – 将DataGrid导出为CSV或Excel

private void btnexport_Click(object sender,RoutedEventArgs e)
{
    ExportToExcel<Employee,Employees> s = new ExportToExcel<Employee,Employees>();
    s.dataToPrint = (Employees)dgEmployee.ItemsSource;
    s.GenerateReport();
}






/// <summary>
/// Class for generator of Excel file
/// </summary>
/// <typeparam name="T"></typeparam>
/// <typeparam name="U"></typeparam>
public class ExportToExcel<T,U>
    where T : class
    where U : List<T>
{
    public List<T> dataToPrint;
    // Excel object references.
    private Excel.Application _excelApp = null;
    private Excel.Workbooks _books = null;
    private Excel._Workbook _book = null;
    private Excel.Sheets _sheets = null;
    private Excel._Worksheet _sheet = null;
    private Excel.Range _range = null;
    private Excel.Font _font = null;
    // Optional argument variable
    private object _optionalValue = Missing.Value;

    /// <summary>
    /// Generate report and sub functions
    /// </summary>
    public void GenerateReport()
    {
        try
        {
            if (dataToPrint != null)
            {
                if (dataToPrint.Count != 0)
                {
                    Mouse.SetCursor(Cursors.Wait);
                    CreateExcelRef();
                    FillSheet();
                    OpenReport();
                    Mouse.SetCursor(Cursors.Arrow);
                }
            }
        }
        catch (Exception e)
        {
            MessageBox.Show("Error while generating Excel report");
        }
        finally
        {
            ReleaSEObject(_sheet);
            ReleaSEObject(_sheets);
            ReleaSEObject(_book);
            ReleaSEObject(_books);
            ReleaSEObject(_excelApp);
        }
    }
    /// <summary>
    /// Make Microsoft Excel application visible
    /// </summary>
    private void OpenReport()
    {
        _excelApp.Visible = true;
    }
    /// <summary>
    /// Populate the Excel sheet
    /// </summary>
    private void FillSheet()
    {
        object[] header = CreateHeader();
        WriteData(header);
    }
    /// <summary>
    /// Write data into the Excel sheet
    /// </summary>
    /// <param name="header"></param>
    private void WriteData(object[] header)
    {
        object[,] objData = new object[dataToPrint.Count,header.Length];

        for (int j = 0; j < dataToPrint.Count; j++)
        {
            var item = dataToPrint[j];
            for (int i = 0; i < header.Length; i++)
            {
                var y = typeof(T).InvokeMember
        (header[i].ToString(),BindingFlags.GetProperty,null,item,null);
                objData[j,i] = (y == null) ? "" : y.ToString();
            }
        }
        AddExcelRows("A2",dataToPrint.Count,header.Length,objData);
        AutoFitColumns("A1",dataToPrint.Count + 1,header.Length);
    }
    /// <summary>
    /// Method to make columns auto fit according to data
    /// </summary>
    /// <param name="startRange"></param>
    /// <param name="rowCount"></param>
    /// <param name="colCount"></param>
    private void AutoFitColumns(string startRange,int rowCount,int colCount)
    {
        _range = _sheet.get_Range(startRange,_optionalValue);
        _range = _range.get_Resize(rowCount,colCount);
        _range.Columns.AutoFit();
    }
    /// <summary>
    /// Create header from the properties
    /// </summary>
    /// <returns></returns>
    private object[] CreateHeader()
    {
        PropertyInfo[] headerInfo = typeof(T).GetProperties();

        // Create an array for the headers and add it to the
        // worksheet starting at cell A1.
        List<object> objHeaders = new List<object>();
        for (int n = 0; n < headerInfo.Length; n++)
        {
            objHeaders.Add(headerInfo[n].Name);
        }

        var headerToAdd = objHeaders.ToArray();
        AddExcelRows("A1",1,headerToAdd.Length,headerToAdd);
        SetHeaderStyle();

        return headerToAdd;
    }
    /// <summary>
    /// Set Header style as bold
    /// </summary>
    private void SetHeaderStyle()
    {
        _font = _range.Font;
        _font.Bold = true;
    }
    /// <summary>
    /// Method to add an excel rows
    /// </summary>
    /// <param name="startRange"></param>
    /// <param name="rowCount"></param>
    /// <param name="colCount"></param>
    /// <param name="values"></param>
    private void AddExcelRows
    (string startRange,int colCount,object values)
    {
        _range = _sheet.get_Range(startRange,colCount);
        _range.set_Value(_optionalValue,values);
    }       
    /// <summary>
    /// Create Excel application parameters instances
    /// </summary>
    private void CreateExcelRef()
    {
        _excelApp = new Excel.Application();
        _books = (Excel.Workbooks)_excelApp.Workbooks;
        _book = (Excel._Workbook)(_books.Add(_optionalValue));
        _sheets = (Excel.Sheets)_book.Worksheets;
        _sheet = (Excel._Worksheet)(_sheets.get_Item(1));
    }
    /// <summary>
    /// Release unused COM objects
    /// </summary>
    /// <param name="obj"></param>
    private void ReleaSEObject(object obj)
    {
        try
        {
            System.Runtime.InteropServices.Marshal.ReleaseComObject(obj);
            obj = null;
        }
        catch (Exception ex)
        {
            obj = null;
            MessageBox.Show(ex.Message.ToString());
        }
        finally
        {
            GC.Collect();
        }
    }
}