How can I drop file to my form when application is running in administrative privilages

Question

4.00/5 (2 votes)

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I have a simple application in C#.net on which i may drop any file from explorer and it shows the file link.
using this code

C#

private void Form1_DragEnter(object sender, DragEventArgs e)
        {
            if (e.Data.GetDataPresent(DataFormats.FileDrop))
            {
                e.Effect = DragDropEffects.Copy;
            }
            else
            {
                e.Effect = DragDropEffects.None;
            }
        }
private void Form1_DragDrop(object sender, DragEventArgs e)
        {
            Array a = (Array)e.Data.GetData(DataFormats.FileDrop);
            if (a != null)
            {
                string s = a.GetValue(0).ToString();
                MessageBox.Show(s);


            }

        }

But when I run this application as an administrator. The application stops dropping the files. And and mouse arrow changes looks like file drop is not allowed appears instead of file copy arrow on the form.

How may I solve it? I want to enable drop in any condition. either app is running in as administrator or normal user.

Any one if help on this.? Or any workaround will be highly appreciated.
Thank you.

Posted 20-Feb-14 8:04am

Asad Nawaz

Updated 20-Feb-14 9:33am

v3

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Comments

Sergey Alexandrovich Kryukov 20-Feb-14 14:09pm

Never heard of such things. What is "round slash"? Anyway, I think there is not enough information to sort it out.
—SA

Asad Nawaz 20-Feb-14 14:20pm

That below symbol is a round slash.
Ø

Sergey Alexandrovich Kryukov 20-Feb-14 15:19pm

You report was too misleading. I though it's "empty set", but it is not, and not "round slash", of course.
This is 00D8, "Latin Capital Letter O With Stroke". You could find it out by yourself, because it's easier on your side.

And sorry, your information is not enough to help you.

—SA

Asad Nawaz 20-Feb-14 15:34pm

changed the description.
now more descriptive

1 solution

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Dave Kreskowiak · Accepted Answer · 2014-02-20T08:16:00

Solution 1

You can't solve it. It's a HUGE security violation to allow interaction between non-priviledged and priviledged processes. By allowing this, you're essentially giving the non-admin process (the Desktop) more priviledges than allowed by the users login.

Posted 20-Feb-14 8:16am

Dave Kreskowiak

Comments

Asad Nawaz 20-Feb-14 14:26pm

My purpose is to just get the link of that file that is just dragged on the form. I want the link on both ways either privileged or non privileged.
Do you have some work around?

Dave Kreskowiak 20-Feb-14 15:27pm

What did I say in my post?? There is no way to do it because it's a HUGE security violation.

You specifying a reason to me that "it's just this little thing" is not going to convince Microsoft or Windows to let that happen!

Sergey Alexandrovich Kryukov 20-Feb-14 15:32pm

For a record: this is not 100% accurate.

Let me give you one example. I run file manager instances using standard OS Shell API, one with elevated privileges, another is not.
First of all, you certainly can drop file from privilege-elevated instance to another, if the source file is accessible in both, as well as target directory. Note that no OS security protection prevents that. Now, what if the source file is accessible to privilege-elevated instance and not to another instance. Apparently, you still could copy it to some accessible directory, using privilege-elevated instance along. And non-elevated instance could later access it. There is nothing wrong with it. But what happens if you try to drag-n-drop such file? Very logical thing: the copy command is shown, but, upon user's confirmation, the non-elevated instance reports that the source file is inaccessible. Isn't it logical? Isn't it safe.

It looks like in reality the system (I am talking about Windows 7 here) behave safely but is more reasonable and less restrictive than you tried to present here. Drag-n-drop between privilege-elevated and regular process is quite legitimate and does not effectively elevate privileges of the non-elevated process.

—SA

Dave Kreskowiak 20-Feb-14 15:41pm

Every way I've tried dragging and dropping works except the one where you try to drag from a non-elevated to an elevated process. Dragging from an elevated to a non-elevated process works as epxected.

Granted, I didn't dig into it for very long, but I could never get it to work dragging from non-elevated to elevated.

Sergey Alexandrovich Kryukov 20-Feb-14 16:07pm

It depends on what you are doing and how. Not being able to drop anything between such processes is not a rule.
—SA

Dave Kreskowiak 20-Feb-14 19:04pm

I was doing like the OP did. I was taking files on the Desktop and dropping them on a ListBox in an elevated app. It worked fine if run as myself.

Sergey Alexandrovich Kryukov 20-Feb-14 20:59pm

Ha! Interestingly, with the file manager, the file is dropped from the desktop onto non-elevated application, and attempt to do the same with privilege-elevated process, same application, same file and same directory, shows "stop" icon. I described a different scenario above, when dropping between elevated and non-elevated processes does work. Not clear how it could be related to security consideration you put above.
Anyway, something is going on here, not sure it's really reasonable... after all, I can show the same desktop in the non-elevated manager (desktop is actually a directory) and do the same operation freely...

Anyway, thank you for this discussion.

—SA

Dave Kreskowiak 20-Feb-14 21:39pm

no problem. Later

Asad Nawaz 20-Feb-14 15:41pm

Right. Thank you for your proper information.
By this way definitely it's looking not possible.
Actually my application open some image file. There is a open option in the file menu that I may use.
I used drag and drop as a shortcut to open the image file.
I just want to get the link of that file in short way. Usually some times I drop the image from firefox to my windows form app.
I am thinking my form is accessing the file from explorer. That is it use that image file to show in the image box. So I just need the file location of that file by this way.
Is this possible that my application runs both in elevated and normal way so that when file drop action occurs then normal thread receive it and when file drop occurs from elevated thread then my application elevated thread use that information.

Thank you for you good advice.