检查服务器上是否存在文件

Question

I am trying to check if a file is on the server with the C# code behind of my ASP.NET web page. I know the file does exist as I put it on the server in a piece of code before hand. Can anyone see why it is not finding the file. This is the code:

wordDocName = "~/specifications/" + Convert.ToInt32(ViewState["projectSelected"]) + ".doc";
ViewState["wordDocName"] = wordDocName;
if (File.Exists(wordDocName))
{
    btnDownloadWordDoc.Visible = true;
}
else
{
    btnDownloadWordDoc.Visible = false;
}

Answer 1

the file path should be physical not virtual. Use

if (File.Exists(Server.MapPath(wordDocName)))

Answer 2

File.Exists() and probably everything else you want to do with the file will need a real Path.

Your wordDocName is a relative URL.

Simply use

string fileName = Server.MapPath(wordDocName);

Answer 3

Use

Server.MapPath("~/specifications/" + Convert.ToInt32(ViewState["projectSelected"]) + ".doc")

to get the fully-qualified path. That should do the trick for ya.

Answer 4

You need to use Server.MapPath eg

    wordDocName = Server.MapPath("~/specifications/" + Convert.ToInt32(ViewState["projectSelected"]) + ".doc");
    ViewState["wordDocName"] = wordDocName;
    if (File.Exists(wordDocName))
    {
        btnDownloadWordDoc.Visible = true;
    }
    else
    {
        btnDownloadWordDoc.Visible = false;
    }

Answer 5

this might not work if the directory holding the file is referenced by a junction/symbolic link. I have this case in my own application and if I put the REAL path to the file, File.Exists() returns true. But if I use Server.MapPath but the folder is in fact a junction to the folder, it seems to fail. Anyone experienced the same behaviour?

Answer 6

You have to convert the path to a physical path with Server.MapPath(relativePath)

if (File.Exists(filePath))

wordDocName = "~/specifications/" + ViewState["projectSelected"] + ".doc";        
btnDownloadWordDoc.Visible = File.Exists(Server.MapPath(wordDocName));

Answer 7

The character " ~ " is a special char in ASP.NET to get virtual path specifications and simply means " root directory of the application ". Is is not understood by the .NET BCL like the File API and must be mapped first into a physical path with Server.MapPath() as others stated.

Answer 8

string docname="traintatkalantnoy.txt";

string a = (Server.MapPath(docname)); if (File.Exists(a))