This article demonstrates how to use the .NET Framework Process class to start another application from your code and have the code wait for the other application to close before it continues.
When the code waits for the application to finish, there are two options:
Wait indefinitely for the other application to either finish or be closed by the user. -or-
Specify a time-out period after which you can close the application from your code.
This article presents two code samples that demonstrate both approaches. In addition, the time-out example can recognize if the other application has stopped responding and will take the necessary steps to close the application.
Option 1: Wait Indefinitely for the Shelled Application to Finish
This following code sample instructs the shell to open the EULA.txt file. The shell will open the program associated with the .txt file type (usually Microsoft Notepad). The program will wait indefinitely for the application to terminate.
//How to wait for a shelled application to finish//Get the name of the system folderString* sysFolder= Environment::GetFolderPath(Environment::SpecialFolder::System);//Create a new ProcessInfo structureProcessStartInfo * pInfo = new ProcessStartInfo();//Set the file name member of the process info structure.pInfo->FileName = String::Concat(sysFolder, S"\\eula.txt");//Start the process.Process* p = Process::Start(pInfo);//Wait for the window to finish loading.p->WaitForInputIdle();//Wait for the process to end.p->WaitForExit();//Console::WriteLine(S"Code continuing...");MessageBox::Show(S"Code continuing...");
Option 2: Provide a Time-out for the Shelled Application
The following code sample sets a time-out for the shelled application. The time-out for the example is set to 5 seconds. You may want to adjust this number (which is calculated in milliseconds) for your testing.
//Set a time-out value.int timeOut=5000;//Get path to system folder.String* sysFolder= Environment::GetFolderPath(Environment::SpecialFolder::System);//Create a new process info structure.ProcessStartInfo* pInfo = new ProcessStartInfo();//Set file name to open.pInfo->FileName = String::Concat(sysFolder, S"\\eula.txt");//Start the processProcess* p = Process::Start(pInfo);//Wait for window to finish loading.p->WaitForInputIdle();//Wait for the process to exit or time out.p->WaitForExit(timeOut);//Check to see if the process is still running.if (p->HasExited == false) //Process is still running. //Test to see if the process is hung up. if (p->Responding) //Process was responding; close the main window. p->CloseMainWindow(); else //Process was not responding; force the process to close. p->Kill();MessageBox::Show("Code continuing...");
It may be difficult to choose between these two options. The primary purpose of a time-out is to avoid having your application stop responding ("hang") because the other application has stopped responding ("hung"). Time-outs are better suited for a shelled application that performs background processing, in which the user may not know that the other application has stalled or does not have a convenient way to close it.