C# 询问保存下载文件的位置

我正在编写在本地系统中下载excel文件的代码

Microsoft.Office.Interop.Excel.Application excelApp = new Microsoft.Office.Interop.Excel.Application();
Microsoft.Office.Interop.Excel.Workbooks workBooks = excelApp.Workbooks;
Microsoft.Office.Interop.Excel.Workbook workBook = workBooks.Open(@"D:\Myfile.xlsx");
// Microsoft.Office.Interop.Excel.Worksheet workSheet = workBook.Worksheets.get_Item(1);

workBook.SaveCopyAs(@"D:\Copy_Myfile.xlsx");
workBook.Close();

现在的要求不是将文件保存到D驱动器，而是要求用户将文件保存到指定位置

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有什么想法吗？

也许可以通过文件浏览对话框询问他们？您的意思是，用户应该从服务器下载文件并保存到本地驱动器？与

响应类似。传输文件

？

public static void TransmitFile(Page CurrentPage, string FilePath)
// CurrentPage = this when called from CodeBehind
{
    if (File.Exists(FilePath))
    {
        string FileName = Path.GetFileName(FilePath);
        string Extension = Path.GetExtension(FilePath).ToLowerInvariant();
        string ContentType;

        switch (Extension)
        {
            case "xlsx":
                ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
                break;
            case "xls":
                ContentType = "application/vnd.ms-excel";
                break;
            case "csv":
                ContentType = "text/csv";
                break;
            default:
                ContentType = "application/octet-stream";
                break;
        }

        if (CurrentPage != null)
        {
            CurrentPage.Response.ContentType = ContentType;
            CurrentPage.Response.AppendHeader("Content-Disposition", "attachment; filename=" + FileName);
            CurrentPage.Response.TransmitFile(FilePath);
            CurrentPage.Response.End();
        }
        else
            throw new Exception("File transmission failed: cannot access current page");
    }
    else
        throw new Exception("File transmission failed: file not found");
}