Agenda:
1.
Solution and Project in VS.NET
2.
Importance of Main – Entry point of an application
3. Different forms of Main
1.
Solution is a Collection of Projects. One Solution can have many projects and
every project added to the solution can of same language or different language.
2.
The Solution file has the extension .sln.
3.
A Project is a collection of files including Source Code (.vb/.cs),
Resources(.resx), Configuration(.config) files etc…
4.
The project file has the extension .vbproj or .csproj
5. A project when build
(compilation + linking) generates an EXE/DLL as output, which is called as PE.
Time to create our first
MS.Net application: Goto File à
New à Project à Select Visual C# on Left and Console Application on
right. Name = “FirstConApp” – This is the project name Location = “C:Projects\\”.
class Program
{
public
static void Main()
{
Console.WriteLine("Hello C#");
}
}
To Build the Solution Goto
Menu: Build à Build
Solution (Ctrl + Shift + B) To Run the Application
1.
Debug à Start Debugging (F5) – Here
we can use break points and debug the application.
2. Debug à
Start Without Debuggin (Ctrl + F5) - We
can see the output in console window.
When the
project is build the following output file is generated:
Drive:\...\<ProjectName>\bin\debug\<ProjectName>.Exe Note: In
VS.NET 2008, at the time of creating a project we can specify the Framework
Version to be used which can be either 2.0, 3.0 or 3.5.
Mostly the console based applications
are developed in situations where the application should either run as a top
level process or as child process (invoked from another parent process). Commandline
Arguments: This is the best way of providing input to the console based
application.
using System;
class Program
{
static void Main(string[] args) 'args is an array of
commandline arguments.
{
Console.WriteLine("Hello " + args[0]); 'args(0) is
the first command line argument.
}
}
To give Commandline arguments in
Visual Studio: View à Solution
Explorer à Select Project à Right Click à Properties à Debug Tab à Command
Line Arguments à Provide string separated by space
(Args1 Args2 Args3) Or Give at command prompt in console window Drive:\. . . \
ProjectName\ in\debug\<ProjectName>.exe Args1 Args2 Args3
Return
value of Main:
using System;
class
Program
{
static int Main(string[] args) 'args is an array of
commandline arguments.
{
Console.WriteLine("Hello "
+ args[0]); 'args(0) is the first command line argument.
return
0;
}
}
1.
When the application is not used as child process, the return value of main is
not usefull because what ever may return the value, main ends the application
ends and OS will clean all the memory allocated to it.
2. The return value of Main is
used by the current application to communicate its state to the parent process
when the application terminated. The Integer return value can be predefined
with some meaning and the same will be used by the parent process to know the
state of child process which terminated. The return value of an application is
called as EXIT CODE of the application.
Multiple Startup classes in
one project
One Project
can have multiple modules but only one of many modules with valid Main can be
treated as Startup or Entry Point of the application. To Add another File to
Project: Goto Solution Explorer à Right Click on Project à Add à Class
using System;
class
Program2
{
static void Main()
{
Console.WriteLine("Hello Program2");
}
}
To Set Startup Object: View à Solution
Explorer à Project à
Right Click à
Properties à Application Tab à Starup Object à Select Class whose Main should be used as entry point.
Note: The class declared as startup object cannot have more that
one form of Main which are valid for entry point. All classes in the project
can be placed in either in same file or in different files. In either case the
compiler is going to compile them together. i.e. for a dotnet language compiler
files cannot be used as boundries and all the files are compiled together as
one unit.
To open a closed Solution / Project: File
à Open à
Project / Solution à
Give the Path of .sln file.
To develop an application without using
VS.NET (compiling at command prompt)
1.
Open Notepad
2.
Write the code as given above and Save as C:\Demo.CS
3.
Goto Start à Programs
à Microsoft Visual Studio 2008
à Visual Studio Tools à
VS 2008 Command Prompt (so that the
directory of MS.NET Framework is set in “PATH”)
4.
CSC.EXE C:\Demo.CS => Generates Demo.exe
5. Run Demo.exe
Framework
Folder: C:\Windows\Microsoft.Net\Framwork\V3.5.XXXX\
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