Simulate sending a keystroke or keystrokes in C# console app?

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I want to be able to send a keystroke so as to automate opening a program, typing in it and pressing enter. Is there a way to do this? I have a Task Scheduler to wake the computer and run an exe file, but I am not sure how to create the exe file such that it can open an application and do stuff with it automatically (such as enter a username and password to log into an app).

Any and all suggestions would be greatly appreciated!

What I have tried:

I have create a task with Task Scheduler to periodically wake my computer from sleep. I now just need to automate logging in using an app. Thank you!

Posted 19-Apr-23 15:17pm

Pada Temp

Updated 19-Apr-23 19:00pm

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PIEBALDconsult 19-Apr-23 21:43pm

Seek ye the Process and ProcessStart classes (in System.Diagnostics I think).
You will have to redirect the standard input and probably standard output to interact with the process.

Much of what you want can be found in -- https://www.codeproject.com/Articles/70864/ProcessCommunicator

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OriginalGriff · Answer 1 · 2023-04-19T19:00:00

Solution 1

Opening an app is easy:

C#

Process p = new Process();
ProcessStartInfo psi = new ProcessStartInfo();
psi.FileName = @"Path to file";
psi.Arguments = $"List of arguments to start it with";
psi.RedirectStandardInput = true;
psi.RedirectStandardOutput = true;
p.StartInfo = psi;
p.Start();

And sending data to it is also simple:

C#

StreamWriter sw = p.StandardInput;
sw.WriteLine("username");
sw.WriteLine("password");
sw.Close();
}

Posted 19-Apr-23 19:00pm

OriginalGriff

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Pada Temp 20-Apr-23 5:37am

This is super useful. Thank ye :)

As this is an app wih graphical gui with a login and password, would there be arguments to start it with in the line
psi.Arguments = $"List of arguments to start it with"; ?

I also want the C# code to return control to itself after performing actions. the sw.Close() alone does this or would I also maybe add psi.RedirectStandardInput = false; and psi.RedirectStandardOutput = false; ?

PIEBALDconsult 20-Apr-23 8:57am

But you stated that it was a console app in the question!
Automating a GUI app is a whole different matter.

Pada Temp 20-Apr-23 10:26am

ah sorry what i meant is that C# code from which this is occuring is a console app. i want to have the console app open a GUI app, which now I can do with OriginalGriff's code. then i want the console app to at, the minimum, simulate pressing enter key, so as to have the GUI app log in with pre-populated info on the splash screen....ideally, i would want the console app to do more complex stuff with the GUI app, such as perhaps enter a username and password, prior to simulating a keystroke enter, and then maybe do stuff in the GUI app that a user might do.

PIEBALDconsult 20-Apr-23 10:35am

I don't have any examples handy (at the office), but what simple examples I have use the Process class to find the GUI application window, then use API calls to find a specific button (such as the OK button), and then click it. Maybe someone else will respond, otherwise I'll have a look when I get home.

Pada Temp 20-Apr-23 11:28am

would be most appreciated if you remember to get around to it. you have been already so helpful and i have a good point of reference for further research! cheers!

Pada Temp 20-Apr-23 7:03am

update: works with flying colors except that when i do sw.WriteLine("\n") or anything else in the writelines, such as "username" i am not seeing any corresponding action on screen in the app. the app is able to open though using the process stuff, thanks to you! any suggestions? probably i'm doing something wrong, as usual :))

Pada Temp 20-Apr-23 7:04am

also update: had to include a psi.UseShellExecute = false; line per an error message.

Pada Temp 20-Apr-23 7:48am

another update: was able to use SendKeys (Actually SendWait because of weird windows thing) to get the thing to type text in the application after opening....however this needs to use Windows.Forms which seems to be a less sophisticated, worse way than using Streamwriter?

OriginalGriff 20-Apr-23 9:58am

GUI apps don't use StandardInput - they accept messages from the OS that a key id down, up , or pressed instead. So a stream won't work, and Windows is not designed to make automating other GUI apps simple!

INstead, you need to use SendKeys / SendWait but even then, what you need to send will depend on the target app - you may need to send TAB characters to move between fields and so on.