Tutorial: Using Sockets In C#

Dr. Thomas E. Hicks
Computer Science Department
Trinity University 
About This Tutorial 
This tutorial will be a bit confusing in that we shall attempt to work with two different C# applications somewhat simultaneously. A single program, which functions as both a server and a client, could be constructed; the logic tends to be more complex. We shall develop a Server Application and a Client Application. 
After connecting the Client Application to the Server Application, we shall transfer data back and forth between them. We shall show a technique to have the data, transferred to the server, update and show automatically; we shall shall show a technique to have the data, transferred to the client, buffered and displayed upon request.
 In order to reduce confusion, I shall use blue when working with server, I shall use maroon when working with the client. 

Create The Server Application 
1] Create folder C:\Sockets\ServerApp 
2] Start Visual Studio 2005. Using the mouse, hold down the File Menu -> Select New -> select Project


 
3] Select Project Type = Visual C#. Template = Windows Application template. Name = ServerApp. 
    Location = C:\Sockets\ServerApp Unselect Create  Directory. Push/Select the OK button.


4] Folder C:\Sockets\ServerApp now contains the c# project and support files for our server application.


 

We Shall Create A Socket Server Application That Looks Something Like This 


 
 

The ServerForm - GroupBox1 
1] Create a 428, 600 form, called ServerForm. Make the title Socket Server Application. Append your name to the end of the title. 
2] Select a font style and color scheme for the ServerForm. 
3] Drag a GroupBox, from the Toolbox, to your form. Let the text be Configuration Settings. 

 
4] Drag a Label, from the Toolbox, into GroupBox1. Let the text be Port # 


5] Drag a Textbox, from the Toolbox, into GroupBox1. Let the text be 9999. Let the name be txtPortNo. This will enable us to connect on port # 9999 as a default. 


6] Drag a Button, from the Toolbox, into GroupBox1. Let the text be Send This Data To The Client. Let the name be cmdListen. 

7] Your form should work. Check it out! CTRL+F5 

 


The ServerForm - GroupBox1 
The ServerForm - GroupBox2 

1] Drag a GroupBox, from the Toolbox, to your form. Let the text be Data To Send To Client. 
 
2] Drag a Textbox, from the Toolbox, into GroupBox2. Let the name be txtSendData. Let enable be false. Set the background color to black. Set the font color to black. 

3] Drag a Button, from the Toolbox into GroupBox2. Let the text be Start Server Listening On This Port #. Let the name beCmdSendData. Let enable be false. 

4] Your form should work. Check it out! CTRL+F5



The ServerForm - GroupBox3 
1] Drag a GroupBox, from the Toolbox, to your form. Let the text be Data Continuously Received From Client.
 
2] Drag a Textbox, from the Toolbox into GroupBox3. Let the name be txtDataReceived. Let enable be false. Set the background color to black. Set the font color to black. 

3] Drag a Button, from the Toolbox into GroupBox2 Let the text be Clear Server Data. Let the name be CmdClearData. Let enable be false. 

4] Your form should work. Check it out! CTRL+F5



5] We shall add some code to the Server form shortly!
Create The Client Application 
1] Create folder C:\Sockets\ClientApp 
2] Start Visual Studio 2005. Using the mouse, hold down the File Menu -> Select New -> select Project
 
3] Select Project Type = Visual C#. Template = Windows Application template. Name = ClientApp. 
    Location = C:\Sockets\ClientApp Unselect Create  Directory. Push/Select the OK button. 
 
4] Folder C:\Sockets\ServerApp now contains the c# project and support files for our server application. 
 

We Shall Create A Socket Client Application That Looks Something Like This 


 \\\

The ClientForm - GroupBox1 
1] Create a 428, 600 form, called ClientForm. Make the title Socket Client Application. Append your name to the end of the title.
2] Select a font style and color scheme for the ClientForm. I would encourage you to select a color different from that of the ServerApp.
3] Drag a GroupBox, from the Toolbox, to your form. Let the text be Configuration Settings. 

4] Drag a Label, from the Toolbox, into GroupBox1. Let the text be Host I.P. Address 

5] Drag a Textbox, from the Toolbox, into GroupBox1. Let the text be 127.0.0.1. Let the name be txtIPAddress. Address 127.0.0.1 is the default for this system; by using it as a default, we can easily develop and test both the server and the client on the same computer and then migrate to multiple computers for final testing. 
 
6] Drag a Button, from the Toolbox, into GroupBox1. Let the text be Send This Data To The Client. Let the name be cmdListen.
 
 7] Your form should work. Check it out! CTRL+F5



The ClientForm - GroupBox2 
1] Drag a GroupBox, from the Toolbox, to your form. Let the text be Data To Send To Client. 
 
2] Drag a Textbox, from the Toolbox, into GroupBox2. Let the name be txtSendData. Let enable be false. Set the background color to black. Set the font color to black. 

3] Drag a Button, from the Toolbox into GroupBox2. Let the text be Start Client Listening On This Port #. Let the name be CmdSendData. Let enable be false. 

4] Your form should work. Check it out! CTRL+F5



The ClientForm - GroupBox3 
1] Drag a GroupBox, from the Toolbox, to your form. Let the text be Data Continuously Received From Client.
 
2] Drag a Textbox, from the Toolbox into GroupBox3. Let the name be txtDataReceived. Let enable be false. Set the background color to black. Set the font color to black.

3] Drag a Button, from the Toolbox into GroupBox2 Let the text be Clear Client Data. Let the name be CmdClearData. Let enable be false. 

4]] Your form should work. Check it out! CTRL+F5



5] We shall add some code to the Client form shortly!


The Code Behind Buttons