图像上传到文件系统[关闭]

Question

如何将图像上传到文件系统？

Answer 1

这是代码示例：

你的html：

<input type="file" name="Pic_0001">

注意：html 输入控件必须位于表单内

现在你的 asp .net 代码：

    'this is your file name at html page
    Dim HtmlFilename As String = "Pic_0001"

    'the place to manipulate all uploaded files
    Dim collection As System.Web.HttpFileCollection
    collection = Page.Request.Files

    'for example, you have selected a picture file named hotdog.jpg in browser
    'this variable will manipulate your hotdog.jpg file
    Dim UploadedFile As System.Web.HttpPostedFile

    'retrieve the reference to your file
    UploadedFile = collection.Item(HtmlFilename)

    'this is the location to save your uploaded file
    Dim WhereToSave As String = "c:\test folder\hotdog.jpg"

    'this is your folder that will contain the uploaded file
    Dim Folderpath As String = System.IO.Path.GetDirectoryName(WhereToSave)

    'now do checking if the folder exists, if not create the folder
    'NOTE: this step is needed to prevent folder not exists error
    If System.IO.Directory.Exists(Folderpath) = False Then
        System.IO.Directory.CreateDirectory(Folderpath)
    End If

    'now actually save your file to the server
    UploadedFile.SaveAs(WhereToSave)

Answer 2

使用FileUpload control。

例如（根据链接的 MSDN 文章修改），如果您只想要一个简单的表单，将文件上传到服务器上的路径，您可以从以下内容开始：

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

<script runat="server">
    protected void UploadFileAction_Click(object sender, EventArgs e)
    {
        var fileStoragePath = Server.MapPath("~/Uploads");

        if (fileUploader.HasFile)
        {
            fileUploader.SaveAs(Path.Combine(fileStoragePath, fileUploader.FileName));
            outputLabel.Text = string.Format(
                "File Name: {0}<br />File Size: {1}kb<br />Content Type: {2}",
                fileUploader.PostedFile.FileName,
                fileUploader.PostedFile.ContentLength,
                fileUploader.PostedFile.ContentType
            );
        }
        else
            outputLabel.Text = "You have not specified a file.";
    }
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Upload A File</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:FileUpload ID="fileUploader" runat="server" /><br />
        <br />
        <asp:Button ID="uploadFileAction" runat="server" OnClick="UploadFileAction_Click" Text="Upload File" />&nbsp;<br />
        <br />
        <asp:Label ID="outputLabel" runat="server"></asp:Label></div>
    </form>
</body>
</html>

FileUpload 控件最终在客户端呈现为一个简单的<input type="file" />（当然，设置了更多属性），作为整体 ASP.NET 表单元素管理的一部分，就像任何其他服务器端表单控件一样.

在您的问题中，您特别提到了上传“图片”。虽然这段代码可能会让您到达那里，但您也可能会隐含地问第二个问题，即“我如何确保上传的文件是图像？”如果是这样，您可以在this question 和this one 的答案中很好地概述了一些选项（它指的是其他问题的更多答案，这是一个热门话题）。与往常一样，服务器端验证是必要的，即使客户端验证仍被推荐用于良好的用户体验。永远不要隐式信任客户端验证，还要始终验证服务器上的用户输入。