Console.SetError() Method in C#

The Console.SetError(TextWriter) Method sets the Error property of the specified StreamWriter i.e., it redirects the standard error stream to a file. As the console is set with this StreamWriter object, the WriteLine() method can be called to write the error into the file.

Syntax: public static void SetError (System.IO.StreamWriter newError);

Parameter:
newError: It is a stream which is the new standard error output.

Exception: This method will throw the ArgumentNullException if the parameter passed is null. Also, since it uses the StreamWriter object, it’s exceptions should also be taken care of.

Example: In this example, the SetError() method is used to set the StreamWriter object to the console, and the error messages will be written into a log file from the Console.

// C# program to demonstrate
// the SetError() method
using System;
using System.IO;

class GFG {

    // Main Method
    static void Main()
    {
        // Define file to receive error stream.
        string fn = "F:\\gfg_error.log";

        // Define the new error StreamWriter object
        StreamWriter errStream = new StreamWriter(fn);

        // Redirect standard error stream to file.
        Console.SetError(errStream);

        // Write the error message into the Log file
        Console.Error.WriteLine("Error line is written into the log file.");
        Console.Error.WriteLine("Keep coding geeks!");

        // Close redirected error stream.
        Console.Error.Close();
    }
}

Output: The gfg_error.log file will now have the error messages in it.

Reference:

• https://docs.microsoft.com/en-us/dotnet/api/system.console.seterror?view=netframework-4.7.2#System_Console_SetError_System_IO_TextWriter_