 Sometimes, you may require running the .NET applications from Command window (MS-DOS window).
 At that time, follow the below steps:

1) Click on “Start” – “Run”.
2) Type “cmd”.
3) Press Enter.
4) A MS-DOS prompt window will be opened.
5) Now, locate the “bin” folder of the required application, by using the following commands. For example, let us imagine that there is a project named “ConsoleApplication1” in “D:” drive.
6) Now, you got the output as
Welcome to C# Console Programming…

 All of the previous examples in the material have been given without any arguments to the Main() method.
 However, when the program is invoked, you can pass some arguments to the Main() method, if required.
 C#’s Main() method receives those arguments in string array format, traditionally called as “args” (of course, C# allows you change the name also).

Syn: Main(string[] args)

 Those arguments could be called as “Command line arguments”.
 You can use these command line arguments for the internal logic in the application.
Demo on Main() method arguments

For example, Let us create this application on “D:”

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ArgsDemo
{
class Program
{
static void Main(string[] args)
{
if (args.Length > 0)
{
Console.WriteLine(args.Length + " arguments found. Those are:");
for (int i = 0; i < args.Length; i++)
Console.WriteLine(args[i]);
}
else
Console.WriteLine("No arguments found...");
Console.Read();
}
}
}

 As you know already, Main() method is nothing but the entry point of the application.
 Most commonly, a .NET application contains only one Main() method.
 If needed, you are supposed to define multiple Main() methods also.
 But, at run time, only one Main() method can be specified as “Entry Point”. This specification can be changed using the project properties.
 To understand better, we start with an example on this.
Demo on Multiple Main() Methods

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace MultipleMainMethods
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("This is the Main() method in Program class.");
Console.Read();
}
}
class MySample
{
static void Main(string[] args)
{
Console.WriteLine("This is the Main() method in MySample class.");
Console.Read();
}
}
}

 When this program is compiled, the compiler shows 2 compile time errors.
 It’s because, two Main() methods are found in MySample class and Program class; So that the compiler can’t understand which Main() method is to be used as exact entry point.
 To specify the required entry point, we have to change “Startup Object” option in the project properties.
 To open the project properties, click on “Project” menu – “Properties”.
 Then the project properties will be opened. Now, observe the “Startup Object” option.
 The “Startup Object” option contains two options.
1) (Not Set)
2) MultipleMainMethods.Program
(“MultipleMainMethods” is the project name).
 Whenever it is set to “(Not Set)”, C# compiler automatically detects the Main() method, where it is exists. This is the default value in the “Startup object” option. But this fails whenever multiple Main() methods are defined.
 Now you have to select the required class that contains the desired Main() method as entry point.


 Finally close the properties tab and come to “Program.cs” tab.
 Now run the application.
 Then you can get the output from the desired Main() method.