It's been a long time since I've had to work with WebForms but I'm having to update an old website. I'm trying to make a page that will allow the user to download a file to their machine. I can get the list of files in a directory as well as display it in a table, however, I'm trying to assign the file name to the command argument of a button so that I'll know the name of the file to go get in the button event. I can't seem to find the correct way to get the value out of the folder object to populate the command argument. No errors, it's just blank. Any suggestions?
var listFiles = dir.GetFiles();
<%
foreach(var file in listFiles) { %>
<tr>
<td> </td>
<td><%= file.Name %></td>
<td><%= file.Length %></td>
<td><%= file.CreationTime.ToString("MM/dd/yyyy HH:mm") %></td>
<td>
<asp:LinkButton ID="btnDownload" runat="server"
CommandArgument='<%#Eval("file.Name") %>'
CommandName="DownloadTechFile"
OnCommand="DownloadFile"
ToolTip="Downloaded file">
<span aria-hidden="true" ></span>
</asp:LinkButton>
</td>
</tr>
<% } %>
protected void DownloadFile(object sender, CommandEventArgs e)
{
Alert.Hide();
var fileName = e.CommandArgument.ToString();
var fileFullPath = Path.Combine(FileFolderPath, fileName);
if (string.IsNullOrWhiteSpace(fileName) == false)
{
WebClient req = new WebClient();
HttpResponse response = HttpContext.Current.Response;
try
{
response.Clear();
response.ClearContent();
response.ClearHeaders();
response.Buffer = true;
response.AddHeader("Content-Disposition", "attachment;filename=" fileName);
byte[] data = req.DownloadData(fileFullPath);
//byte[] data = req.DownloadData(Server.MapPath(fileFullPath));
response.BinaryWrite(data);
response.End();
Alert.Show(AlertType.Success, "File downloaded.");
}
catch (Exception ex)
{
logger.Error("Error downloading file from {0}. {1} | {2} | {3}", fileFullPath, ex.Message, ex.StackTrace, ex.InnerException);
Alert.Show(AlertType.Error, string.Format("Error trying to download file: {0}", fileName));
}
}
}
UPDATE: This is what I came up with in case someone else could use it.
<asp:GridView ID="gvFiles" runat="server" AutoGenerateColumns="false" CssClass="table borderless" HeaderStyle-CssClass="fileheader">
<Columns>
<asp:BoundField DataField="FileName" HeaderText="File Name" />
<asp:BoundField DataField="FileSize" HeaderText="File Size" />
<asp:BoundField DataField="Date" HeaderText="Created On" />
<asp:TemplateField HeaderText="">
<ItemTemplate>
<asp:LinkButton ID="btnDownload" runat="server"
CommandArgument='<%# Eval("FileName") %>'
OnClick="DownloadFile"
ToolTip="Downloaded file">
<span aria-hidden="true" ></span>
</asp:LinkButton>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
void LoadGrid()
{
// create a table for the files, populate, and then bind.
DataTable dtFiles = new DataTable();
dtFiles.Columns.Add("Date", typeof(string));
dtFiles.Columns.Add("FileSize", typeof(string));
dtFiles.Columns.Add("FileName", typeof(string));
DirectoryInfo fileDirectory = new DirectoryInfo(FileFolderPath);
foreach (FileInfo file in fileDirectory.GetFiles("*.txt"))
{
DataRow dr = dtFiles.NewRow();
dr["Date"] = file.CreationTime.ToString("MM/dd/yyyy HH:mm");
dr["FileSize"] = Utility.GetBytesReadable(file.Length);
dr["FileName"] = file.Name;
dtFiles.Rows.Add(dr);
}
dtFiles.DefaultView.Sort = "Date DESC";
gvFiles.DataSource = dtFiles;
gvFiles.DataBind();
}
protected void DownloadFile(object sender, EventArgs e)
{
var fileName = (sender as LinkButton).CommandArgument;
var fileFullPath = Path.Combine(FileFolderPath, fileName);
string mineType = MimeMapping.GetMimeMapping(fileFullPath);
if (string.IsNullOrWhiteSpace(fileName) == false)
{
byte[] binFile = File.ReadAllBytes(fileFullPath);
Response.ContentType = mineType;
Response.AppendHeader("Content-Disposition", "attachment; filename=" fileName);
Response.BinaryWrite(binFile);
Response.End();
}
}
CodePudding user response：
You can say use a gridview, and say like this:
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false" CssClass="table">
<Columns>
<asp:BoundField DataField="File Name" HeaderText="File" />
<asp:BoundField DataField="Date" HeaderText="Date" />
<asp:BoundField DataField="File Size" HeaderText="Size" />
<asp:TemplateField HeaderText="Select" ItemStyle-HorizontalAlign="Center">
<ItemTemplate>
<asp:HyperLink ID="HyperLink1" runat="server" CssClass="btn btn-default"
NavigateUrl='<%# Eval("Path") %>' >Down Load</asp:HyperLink>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
And code behind can be this:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
LoadGrid();
}
void LoadGrid()
{
// create a table for the files
DataTable MyTable = new DataTable();
MyTable.Columns.Add("Date", typeof(string));
MyTable.Columns.Add("File Size", typeof(string));
MyTable.Columns.Add("File Name", typeof(string));
MyTable.Columns.Add("Path", typeof(string));
string strURLFolder = "~/Content/Animals/";
string strFolder = Server.MapPath(strURLFolder);
DirectoryInfo MyDir = new DirectoryInfo(strFolder);
FileInfo[] MyFiles = MyDir.GetFiles("*.*");
foreach (FileInfo MyFile in MyDir.GetFiles("*.*"))
{
DataRow OneRow = MyTable.NewRow();
OneRow["Date"] = MyFile.LastAccessTime;
OneRow["File Size"] = (MyFile.Length / 1024).ToString() " KB";
OneRow["File Name"] = MyFile.Name;
OneRow["Path"] = strURLFolder MyFile.Name;
MyTable.Rows.Add(OneRow);
}
MyTable.DefaultView.Sort = "Date";
GridView1.DataSource = MyTable;
GridView1.DataBind();
}
And now we get this:
Now, I suppose you could replace the "hyper-link" with a button, and perhaps read the files as byte stream, and send that to the client, but above should get you started here.
Edit: The user notes they don't want to use a hyper-link (simple link) to the file.
So, we can do it this way:
We drop in a plane jane button into the grid (why then suggest, hint, talk about a "link" when you NOW stated you DO NOT want to use a link? - are we giving out awards for confusing here?).
If you don't want a link, then obviously we don't need nor want to care about, and talk about links then right?????
Ok, so lets remove the hyper link, and drop in a plane jane button into the grid view like this:
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false" CssClass="table">
<Columns>
<asp:BoundField DataField="File Name" HeaderText="File" />
<asp:BoundField DataField="Date" HeaderText="Date" />
<asp:BoundField DataField="File Size" HeaderText="Size" />
<asp:TemplateField HeaderText="Select" ItemStyle-HorizontalAlign="Center">
<ItemTemplate>
<asp:Button ID="cmdDownLoad" runat="server" Text="Download" css
OnClick="cmdDownLoad_Click" />
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
So, code to load as before, and now we get/have this:
protected void cmdDownLoad_Click(object sender, EventArgs e)
{
Button btn = sender as Button;
GridViewRow gRow = btn.NamingContainer as GridViewRow;
string sFileOnly = gRow.Cells[0].Text;
string sFile = Server.MapPath("~/Content/Animals/" sFileOnly);
string sMineType = MimeMapping.GetMimeMapping(sFile);
byte[] binFile = File.ReadAllBytes(sFile);
Response.ContentType = sMineType;
Response.AppendHeader("Content-Disposition", "attachment; filename=" sFileOnly);
Response.BinaryWrite(binFile);
Response.End();
}
So, we should see say this:
