[英]Download file using ASP.NET Core
創建文件后,我嘗試下載excel文件,但出現以下錯誤:
UnauthorizedAccessException:拒絕訪問路徑“ C:\\ Users \\用戶名\\ Documents \\ Visual Studio 2015 \\ Projects \\ Project_Name \\ src \\ Project_Name \\ wwwroot”。
文件創建成功,問題出在下載方法中。
我已經嘗試執行以下操作來解決此錯誤:
這是代碼:
private readonly IHostingEnvironment _hostingEnvironment;
public EmployeeController(ApplicationDbContext context, IHostingEnvironment hostingEnvironment)
{
_hostingEnvironment = hostingEnvironment;
}
public void createFile()
{
string wwwrootPath = _hostingEnvironment.WebRootPath;
string fileName = @"Employees.xlsx";
FileInfo file = new FileInfo(Path.Combine(wwwrootPath, fileName));
if (file.Exists)
{
file.Delete();
file = new FileInfo(Path.Combine(wwwrootPath, fileName));
}
using (ExcelPackage package = new ExcelPackage(file))
{
ExcelWorksheet worksheet = package.Workbook.Worksheets.Add("Employee");
worksheet.Cells[1, 1].Value = "ID";
worksheet.Cells[1, 2].Value = "Name";
worksheet.Cells[1, 3].Value = "Gender";
worksheet.Cells[1, 4].Value = "Salary (in $)";
worksheet.Cells["A2"].Value = 1000;
worksheet.Cells["B2"].Value = "Jon";
worksheet.Cells["C2"].Value = "M";
worksheet.Cells["D2"].Value = 5000;
worksheet.Cells["A3"].Value = 1001;
worksheet.Cells["B3"].Value = "Graham";
worksheet.Cells["C3"].Value = "M";
worksheet.Cells["D3"].Value = 10000;
worksheet.Cells["A4"].Value = 1002;
worksheet.Cells["B4"].Value = "Jenny";
worksheet.Cells["C4"].Value = "F";
worksheet.Cells["D4"].Value = 5000;
package.Save();
downloadFile(wwwrootPath);
}
}
public FileResult downloadFile(string filePath)
{
var mimeType = "application/vnd.ms-excel";
FileStream fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read);
return File(fileStream, mimeType, "Employees.xlsx");
}
注意:我沒有在IIS中進行項目的部署。
最好的祝福
在ASP.NET Core中,應使用PhysicalFileProvider
類訪問實際系統的文件。 如果您查看文檔中的“ 文件提供者”部分:
PhysicalFileProvider提供對物理文件系統的訪問。 它包裝System.IO.File類型(用於物理提供程序),對目錄及其子目錄的所有路徑進行范圍界定。 這種作用域限制了對某個目錄及其子目錄的訪問,從而阻止了對該邊界之外文件系統的訪問。
以下應該為您工作:
string wwwrootPath = _hostingEnvironment.WebRootPath;
string fileName = @"Employees.xlsx";
IFileProvider provider = new PhysicalFileProvider(wwwrootPath);
IFileInfo fileInfo = provider.GetFileInfo(fileName);
var readStream = fileInfo.CreateReadStream();
// PhysicalFileProvider.GetFileInfo
返回的實例PhysicalFileInfo
提供實現IFileInfo.CreateReadStream
方法。
我測試了您的代碼,錯誤消失了,但是文件沒有被下載。 這是代碼:
public FileResult downloadFile(string filePath, string fileName)
{
IFileProvider provider = new PhysicalFileProvider(filePath);
IFileInfo fileInfo = provider.GetFileInfo(fileName);
var readStream = fileInfo.CreateReadStream();
var mimeType = "application/vnd.ms-excel";
return File(readStream, mimeType, fileName);
}
最好的祝福
我在代碼中注意到了兩種情況。 1-如果直接在按鈕中調用下載方法,則會進行下載,但是文件存儲在localhost目錄中,例如http:// localhost:3724 / Area / Controller / downLoadMethod 。 我希望瀏覽器打開下載框,然后選擇存儲文件的位置。
2-如果在我的按鈕中調用了exportMethod,而在exportMethod的內部調用了downloadMethod,則在文件導出后我只會得到一個空白頁,則不會進行下載。
最好的祝福
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