在C＃中执行批处理文件命令

Question

I have the following code in my C# application which loaded a batch file silently using command prompt and executed and returned the result to a string:

System.Diagnostics.Process proc = new System.Diagnostics.Process();
proc.StartInfo.FileName = @"C:\files\send.bat";
proc.StartInfo.RedirectStandardError = false;
proc.StartInfo.RedirectStandardOutput = true;
proc.StartInfo.UseShellExecute = false;
proc.StartInfo.CreateNoWindow = true;
proc.Start();
string strGetInfo = proc.StandardOutput.ReadToEnd();
strCMDOut = strGetInfo.Substring(strGetInfo.Length - 5, 3);
proc.WaitForExit();

I am trying to avoid my application going out to a different file to execute the batch file, rather I wanted to embed it inside my application. So I changed the above code to this:

System.Diagnostics.Process proc = new System.Diagnostics.Process();
System.Diagnostics.ProcessStartInfo startInfo = new System.Diagnostics.ProcessStartInfo();
startInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;
startInfo.FileName = "cmd.exe";
startInfo.Arguments = "@ECHO ON java com.this.test567 send";
startInfo.RedirectStandardOutput = true;
startInfo.UseShellExecute = false;
proc.StartInfo = startInfo;
proc.Start();
string strGetInfo = proc.StandardOutput.ReadToEnd();
strCMDOut = strGetInfo.Substring(strGetInfo.Length - 5, 3);

When the code executes, I can see the command prompt window for a brief moment before it closes and the execution is not working correctly. How can I fix the issue?

Answer 1

Instead of using cmd.exe just use java directly, you should also redirect standard error and check that after the process ends.

System.Diagnostics.Process proc = new System.Diagnostics.Process();
proc.StartInfo.FileName = @"java.exe";
proc.StartInfo.Arguments = "com.this.test567";

proc.StartInfo.RedirectStandardError = true;
proc.StartInfo.RedirectStandardOutput = true;
proc.StartInfo.UseShellExecute = false;
proc.StartInfo.CreateNoWindow = true;
proc.Start();
string strGetInfo = proc.StandardOutput.ReadToEnd();
if(string.IsNullOrEmpty(strGetInfo))
    strGetInfo = proc.StandardError.ReadToEnd();
proc.WaitForExit();

Answer 2

Note that by calling cmd directly, you're effectively making a batch script with whatever you use for in the Arguments Property. Like a .bat file, the command window closes as soon as it's done. To fix this, add a pause command to the end.

startInfo.Arguments = "@ECHO ON java com.this.test567 send\npause";

Answer 3

& seperates commands on a line.

&& executes this command only if previous command's errorlevel is 0.

|| (not used above) executes this command only if previous command's errorlevel is NOT 0

> output to a file

>> append output to a file

< input from a file

| output of one command into the input of another command

^ escapes any of the above, including itself, if needed to be passed to a program

so seperate commands with &

"/k @ECHO ON&java com.this.test567&send"

/k keeps a window open.

so you'll get in cmd

cmd /k @ECHO ON&java com.this.test567&send