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i want to ask for help with opening a file from c# app with associated app. I tried this:

      ProcessStartInfo pi = new ProcessStartInfo(file);
      pi.Arguments = Path.GetFileName(file);
      pi.UseShellExecute = true;
      pi.WorkingDirectory = Path.GetDirectoryName(file);
      pi.FileName = file;
      pi.Verb = "OPEN";
      Process.Start(pi);

or this:

      Process.Start(file);

where string file in both examples represents full path to the file trying to open. Now, everything is working well, except the (jpg) images with ACDSee app. Irfanview associations works well, MS office documents too. After trying to open the jpg image associated with acdsee it just runs the acdsee in the notification area and does not open the file.

I discovered, that in the registry CLASSES_ROOT for *.jpg images, there is an ACDSee.JPG value as associated app, and under this key there is in the shell->Open->Command a path:

"C:\Program Files\ACD Systems\ACDSee\ACDSee.exe" /dde

and I thing that this weird /dde is the reason, why i cannot open the file. I realized that in the same reg key shell->Open there is some DDEExec key entry with value [open("%1")]

For Irfan view or other checked app there is not a ddeexec, just the normal command like

"C:\Program Files (x86)\IrfanView\i_view32.exe" "%1"

that can be run from command line after swaping the %1 for file name, but I could not run the command from acdsee entry in the command line :(

So my question is, how can I set up the ProcessStartInfo object to ensure that it will run all the files as it would be in the explorer by doubleclick, the standards and this DDEExec ones? Is there something other like DDEExec that I shoul be aware of? thanks and sorry for my EN

UPDATE: because this question still gets upvotes, I want to clarify that accepted answer works. I only had problem with old version of ACDSee and not with the Process.Start command or with the jpg extension.

Zavael
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3 Answers3

146

Just write

System.Diagnostics.Process.Start(@"file path");

example

System.Diagnostics.Process.Start(@"C:\foo.jpg");
System.Diagnostics.Process.Start(@"C:\foo.doc");
System.Diagnostics.Process.Start(@"C:\foo.dxf");
...

And shell will run associated program reading it from the registry, like usual double click does.

Tigran
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    It seems like he already tried that with `Process.Start(file);`. – Mario S Apr 16 '12 at 12:43
  • "So my question, how can I set up the ProcessStartInfo object to ensure that it will run all the files as it would be in the explorer by doubleclick": the answer is that. He used command line arguments, whatever... but not direct invokation, as much as I see. – Tigran Apr 16 '12 at 12:45
  • @Tigran Mario is right, as I wrote I tried your suggestion as the second example... i wanted to ask my question in manner that clearly this is not the right sollution, as the jpg is not opened! – Zavael Apr 16 '12 at 12:47
  • @Zavael: on my machine it opens windows default editor, so I think on your system it should open simply the latest software installed and associated with that format. – Tigran Apr 16 '12 at 12:50
  • @Tigran as i wrote, if I have Irfanview, its ok, if I have word documents, its ok, even windows viewer works fine, but they have their commands in one reg value... acdsee has there some /dde argument and an DDEExec registry key, tha I think is for build the command together and therefore its not working... and its not only on my machine.. try to install acdsee 4 and than run the code – Zavael Apr 16 '12 at 12:54
  • @Tigran mea culpa, the problem is not in the Process execution, sory for the misleading info :( – Zavael Apr 18 '12 at 07:29
73

In .Net Core (as of v2.2) it should be:

new Process
{
    StartInfo = new ProcessStartInfo(@"file path")
    {
        UseShellExecute = true
    }
}.Start();

Related github issue can be found here

Mehdi Dehghani
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23

This is an old thread but just in case anyone comes across it like I did. pi.FileName needs to be set to the file name (and possibly full path to file ) of the executable you want to use to open your file. The below code works for me to open a video file with VLC.

var path = files[currentIndex].fileName;
var pi = new ProcessStartInfo(path)
{
    Arguments = Path.GetFileName(path),
    UseShellExecute = true,
    WorkingDirectory = Path.GetDirectoryName(path),
    FileName = "C:\\Program Files (x86)\\VideoLAN\\VLC\\vlc.exe",
    Verb = "OPEN"
};
Process.Start(pi)

Tigran's answer works but will use windows' default application to open your file, so using ProcessStartInfo may be useful if you want to open the file with an application that is not the default.

aloisdg
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Tree
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    (: a comment on an old response to an old thread :) Tigran's answer runs the most recently associated program for each file's extensions. Tree's answer forces it to use **vlc.exe**. Zavael's question is about trouble he is _only_ having with **ACDSee.exe** and how it sets up its extension association. I think the authors of ACDSee need to be contacted about this. – Jesse Chisholm Nov 13 '14 at 21:42
  • it was an older version of acdsee and I did not verified it with new one so I didnt contact them, just for the info :) – Zavael Apr 25 '18 at 12:40