Question

How do you open a document as another user?

The document type is unkown (could be pdf, .xls, .doc, images etc).
Document is on a network share, username, domain and password are all known.

I have thoroughly researched this question and I do not beleive the question has been answered here. Please prove me wrong.

This question gets close
Open a shared file under another user and domain?

But unfortunately it opens the file to a filestream, I need to open the file in its associated application.

Answer 1

Check out Runas

runas /user:somedomain\someuser "cmd /c start c:\somedocument.pdf"

It is located at C:\Windows\System32\runas.exe

To open this from a C# application, you could use Process.Start, with the appropriate flags.

Edit

Well, you can skip the use of Runas entirely, since Process.Start can do the same job, and still allow you to specify the password however you like (hard-coded internally, or via the UI).

Simply use cmd.exe /c start <pathToFile> to launch the file via the shell with the associated program:

string cmdPath = Path.Combine(
    Environment.GetFolderPath(Environment.SpecialFolder.System),
    "cmd.exe");
string workingDirectory = @"C:\users\public";
string pathToFile = Path.Combine(workingDirectory, "somefile.png");
string arguments = string.Format("/c start {0}", pathToFile);
var password = new SecureString();
foreach (char c in "usersPassword")
    password.AppendChar(c);

var processStartInfo = new ProcessStartInfo()
{
    FileName = cmdPath,
    Arguments = arguments,
    WorkingDirectory = workingDirectory,
    UserName = "TestUser",
    Domain = Environment.MachineName, // Could use domain
    Password = password,
    UseShellExecute = false,
};
Process.Start(processStartInfo);