将WPF DataGrid导出到Excel

当我将DataGrid导出到Excel时，为什么我的值会更改

字符串351732051316944变为3,51732E + 14

和我的日期时间：2014-01-01 02：09：29.942变成41641,09035

以及如何使其停止？

我用于ExportToExcel的类

public class ExportToExcel<T>
{
    public List<T> dataToPrint;
    // Excel object references.
    private Microsoft.Office.Interop.Excel.Application excelApp = null;
    private Workbooks books = null;
    private Workbook book = null;
    private Sheets sheets = null;
    private Worksheet sheet = null;
    private Range range = null;
    private Font font = null;
    // Optional argument variable
    private object optionalValue = Missing.Value;


    /// Generate report and sub functions
    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);
        }
    }
    /// Make Microsoft Excel application visible
    private void OpenReport()
    {
        excelApp.Visible = true;
    }
    /// Populate the Excel sheet
    private void FillSheet()
    {
        object[] header = CreateHeader();
        WriteData(header);
    }
    /// Write data into the Excel sheet
    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);
    }
    /// Method to make columns auto fit according to data
    private void AutoFitColumns(string startRange, int rowCount, int colCount)
    {
        range = sheet.get_Range(startRange, optionalValue);
        range = range.get_Resize(rowCount, colCount);
        range.Columns.AutoFit();
    }
    /// Create header from the properties
    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;
    }
    /// Set Header style as bold
    private void SetHeaderStyle()
    {
        font = range.Font;
        font.Bold = true;
    }
    /// Method to add an excel rows
    private void AddExcelRows(string startRange, int rowCount, int colCount, object values)
    {
        range = sheet.get_Range(startRange, optionalValue);
        range = range.get_Resize(rowCount, colCount);
        range.set_Value(optionalValue, values);
    }

    /// Create Excel application parameters instances
    private void CreateExcelRef()
    {
        excelApp = new Microsoft.Office.Interop.Excel.Application();
        books = (Workbooks)excelApp.Workbooks;
        book = (Workbook)(books.Add(optionalValue));
        sheets = (Sheets)book.Worksheets;
        sheet = (Worksheet)(sheets.get_Item(1));
    }

    /// Release unused COM objects
    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();
        }
    }
}

我不知道从哪里开始这个问题，但我们会提供任何帮助