Making passcode application in C#

This is a tutorial making a simple passcode application in C#
Video tutorial is included :)

Requirements:

• Visual Studio with C#
• Basic knowledge of C# and Programming

Quick step-by-step:

Step 1: Create a new project

• Start Microsoft Visual Studio 2010
• In Menu, click File - New - Project
• Select Visual C#
• Select Windows Form Applications
• Name your project, eg. Passcode
• Click OK

Step 2: Designing your form

• Begin designing your form by opening the Toolbox
• Your passcode application will have a textbox, numeric button, clear button and enter button.
• Textbox will display entered passcode, numeric button (0,1,2,3 - 9) is for the user to click, clear button is to clear the entered passcode and enter button to check the passcode entered.
• Double-Click or Drag Drop the textbox from toolbox to the form
• Resize the textbox accordingly
• You may want to change the text style and size for this textbox. Right-click on the textbox and click Properties. Change the Font value.
• Rename this textbox, eg. txtPass. Right-click the textbox and change the value of (Name)
• Now, add a button

• Resize and change font styles.
• Change the button text, on Properties, change the value of text to "1" (without quotes)
• Optional: Rename the button, eg. btn1
• Repeat the same step for other numeric button, Clear button and Enter button
• Resize and decorate your form

Step 3: Code your application

• Code the numeric button event, double-click the first button which is 1
• Automatic code will be created for the button click event
• Add this code:
• txtPass.Text = txtPass.Text + "1";
  
• txtPass refer to the textbox you named earlier.
• the code simply append a number 1 (string) to the textbox without deleting previous text
• Repeat the same code for other numeric button
• Code the Clear button, double-click the Clear button.

• Automatic code will be created
• Add this code:
• txtPass.Text = "";
  
• This code will simply replace the textbox with an empty string
• Code the Enter button, double-click the Enter button
• Add this code:
• if (txtPass.Text == "12345")
  { txtPass.Text = "Passed";
  }
  else
  { txtPass.Text = "Wrong Passcode! Please try again";
  }
  
• This code compares the text entered in txtPass with the string value 12345
• If txtPass equals to 12345, it then replaced the text in txtPass to "Passed". You can change eg. letting the user into the application after passcode entered correctly
• Vice-versa for entering wrong passcode combination

 Step 4: Test your passcode application

• To run your application, click on Debug - Start without debugging
• The application will start and try to enter some value
• Finish! :)

Step 5: Automatic exit after entered incorrectly 3 times

• Go back to the code.
• Go to the top, where you can find class text
• Add this variable code under the class:
• int nTry = 0;
• The reason to add the variable here is because the variable value will retain until the application exit
• Now, go back to the Enter button code:
• Change to:
• if (txtPass.Text == "12345")
  { txtPass.Text = "Passed";
  }
  else
  { txtPass.Text = "Wrong Passcode! Please try again";
  nTry++;
  if (nTry == 3)
  {
  Application.Exit();
  }
  }
  
  
  
• nTry will be incremented each time you entered wrong passcode combination
• If the value of nTry is equal to 3, then the Application.Exit() will be executed.
• Done! Test again with wrong passcode. Enter it three times and see your application will exit itself.

See the video tutorial here:

Note: Since this is a simple passcode application, the security of the application is too weak and some people will find out the real passcode easily.