ASP.NET - FileUpload Web 服务器控件概述（下）

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示例

第一个示例演示如何创建 FileUpload 控件，该控件将文件保存到代码中指定的路径。

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

protected void UploadButton_Click(object sender, EventArgs e)

{

// Specify the path on the server to

// save the uploaded file to.

String savePath = @"c:/temp/uploads/";

// Before attempting to perform operations

// on the file, verify that the FileUpload

// control contains a file.

if (FileUpload1.HasFile)

{

// Get the name of the file to upload.

String fileName = FileUpload1.FileName;

// Append the name of the file to upload to the path.

savePath += fileName;

// Call the SaveAs method to save the

// uploaded file to the specified path.

// This example does not perform all

// the necessary error checking.

// If a file with the same name

// already exists in the specified path,

// the uploaded file overwrites it.

FileUpload1.SaveAs(savePath);

// Notify the user of the name of the file

// was saved under.

UploadStatusLabel.Text = "Your file was saved as " + fileName;

}

else

{

// Notify the user that a file was not uploaded.

UploadStatusLabel.Text = "You did not specify a file to upload.";

}

</script>

<html >

<title>FileUpload Example</title>

</head>

<body>

<div>

<h4>Select a file to upload:</h4>

<asp:FileUpload id="FileUpload1"

runat="server">

</asp:FileUpload>

<asp:Button id="UploadButton"

Text="Upload file"

OnClick="UploadButton_Click"

runat="server">

</asp:Button>

<hr />

<asp:Label id="UploadStatusLabel"

runat="server">

</asp:Label>

</div>

</form>

</body>

</html>

第二个示例演示如何创建 FileUpload 控件，该控件将文件保存到文件系统中针对应用程序的指定目录。

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

protected void UploadButton_Click(object sender, EventArgs e)

{

// Save the uploaded file to an "Uploads" directory

// that already exists in the file system of the

// currently executing ASP.NET application.

// Creating an "Uploads" directory isolates uploaded

// files in a separate directory. This helps prevent

// users from overwriting existing application files by

// uploading files with names like "Web.config".

string saveDir = @"/Uploads/";

// Get the physical file system path for the currently

// executing application.

string appPath = Request.PhysicalApplicationPath;

// Before attempting to save the file, verify

// that the FileUpload control contains a file.

if (FileUpload1.HasFile)

{

string savePath = appPath + saveDir +

Server.HtmlEncode(FileUpload1.FileName);

// Call the SaveAs method to save the

// uploaded file to the specified path.

// This example does not perform all

// the necessary error checking.

// If a file with the same name

// already exists in the specified path,

// the uploaded file overwrites it.

FileUpload1.SaveAs(savePath);

// Notify the user that the file was uploaded successfully.

UploadStatusLabel.Text = "Your file was uploaded successfully.";

}

else

{

// Notify the user that a file was not uploaded.

UploadStatusLabel.Text = "You did not specify a file to upload.";

}

</script>

<html >

<title>FileUpload Class Example</title>

</head>

<body>

<h3>FileUpload Class Example: Save To Application Directory</h3>

<div>

<h4>Select a file to upload:</h4>

<asp:FileUpload id="FileUpload1"

runat="server">

</asp:FileUpload>

<asp:Button id="UploadButton"

Text="Upload file"

OnClick="UploadButton_Click"

runat="server">

</asp:Button>

<hr />

<asp:Label id="UploadStatusLabel"

runat="server">

</asp:Label>

</div>

</form>

</body>

</html>

第三个示例演示如何创建 FileUpload 控件，该控件将文件保存到指定路径并限制可以上载的文件的大小。

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

protected void UploadButton_Click(object sender, EventArgs e)

{

// Specify the path on the server to

// save the uploaded file to.

string savePath = @"c:/temp/uploads/";

// Before attempting to save the file, verify

// that the FileUpload control contains a file.

if (FileUpload1.HasFile)

{

// Get the size in bytes of the file to upload.

int fileSize = FileUpload1.PostedFile.ContentLength;

// Allow only files less than 2,100,000 bytes (approximately 2 MB) to be uploaded.

if (fileSize < 2100000)

{

// Append the name of the uploaded file to the path.

savePath += Server.HtmlEncode(FileUpload1.FileName);

// Call the SaveAs method to save the

// uploaded file to the specified path.

// This example does not perform all

// the necessary error checking.

// If a file with the same name

// already exists in the specified path,

// the uploaded file overwrites it.

FileUpload1.SaveAs(savePath);

// Notify the user that the file was uploaded successfully.

UploadStatusLabel.Text = "Your file was uploaded successfully.";

}

else

{

// Notify the user why their file was not uploaded.

UploadStatusLabel.Text = "Your file was not uploaded because " +

"it exceeds the 2 MB size limit.";

}

else

{

// Notify the user that a file was not uploaded.

UploadStatusLabel.Text = "You did not specify a file to upload.";

}

</script>

<html >

<title>FileUpload Class Example</title>

</head>

<body>

<div>

<h4>Select a file to upload:</h4>

<asp:FileUpload id="FileUpload1"

runat="server">

</asp:FileUpload>

<asp:Button id="UploadButton"

Text="Upload file"

OnClick="UploadButton_Click"

runat="server">

</asp:Button>

<hr />

<asp:Label id="UploadStatusLabel"

runat="server">

</asp:Label>

</div>

</form>

</body>

</html>

第四个示例演示如何创建 FileUpload 控件，该控件将文件保存到指定路径并且只允许上载扩展名为 .doc 或 .xls 的文件。

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

protected void UploadBtn_Click(object sender, EventArgs e)

{

// Specify the path on the server to

// save the uploaded file to.

string savePath = @"c:/temp/uploads";

// Before attempting to save the file, verify

// that the FileUpload control contains a file.

if (FileUpload1.HasFile)

{

// Get the name of the file to upload.

string fileName = Server.HtmlEncode(FileUpload1.FileName);

// Get the extension of the uploaded file.

string extension = System.IO.Path.GetExtension(fileName);

// Allow only files with .doc or .xls extensions

// to be uploaded.

if ((extension == ".doc") | (extension == ".xls"))

{

// Append the name of the file to upload to the path.

savePath += fileName;

// Call the SaveAs method to save the

// uploaded file to the specified path.

// This example does not perform all

// the necessary error checking.

// If a file with the same name

// already exists in the specified path,

// the uploaded file overwrites it.

FileUpload1.SaveAs(savePath);

// Notify the user that their file was successfully uploaded.

UploadStatusLabel.Text = "Your file was uploaded successfully.";

}

else

{

// Notify the user why their file was not uploaded.

UploadStatusLabel.Text = "Your file was not uploaded because " +

"it does not have a .doc or .xls extension.";

}

</script>

<html >

<title>FileUpload Class Example</title>

</head>

<body>

<div>

<h4>Select a file to upload:</h4>

<asp:FileUpload id="FileUpload1"

runat="server">

</asp:FileUpload>

<asp:Button id="UploadBtn"

Text="Upload file"

OnClick="UploadBtn_Click"

runat="server">

</asp:Button>

<hr />

<asp:Label id="UploadStatusLabel"

runat="server">

</asp:Label>

</div>

</form>

</body>

</html>