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Step 8: Add a Method to Verify Whether the Player Won

You've created a fun game, but it needs an additional item to finish it. The game should end when the player wins, so you need to add a CheckForWinner() method to verify whether the player won.

To add a method to verify whether the player won

  1. Add a CheckForWinner() method to the bottom of your code, below the timer1_Tick() event handler, as shown in the following code.

    /// <summary> 
    /// Check every icon to see if it is matched, by  
    /// comparing its foreground color to its background color.  
    /// If all of the icons are matched, the player wins 
    /// </summary> 
    private void CheckForWinner()
    {
        // Go through all of the labels in the TableLayoutPanel,  
        // checking each one to see if its icon is matched 
        foreach (Control control in tableLayoutPanel1.Controls)
        {
            Label iconLabel = control as Label;
    
            if (iconLabel != null) 
            {
                if (iconLabel.ForeColor == iconLabel.BackColor)
                    return;
            }
        }
    
        // If the loop didn’t return, it didn't find 
        // any unmatched icons 
        // That means the user won. Show a message and close the form
        MessageBox.Show("You matched all the icons!", "Congratulations");
        Close();
    }
    

    The method uses another foreach loop in Visual C# or For Each loop in Visual Basic to go through each label in the TableLayoutPanel. It uses the equality operator (== in Visual C# and = in Visual Basic) to check each label's icon color to verify whether it matches the background. If the colors match, the icon remains invisible, and the player hasn't matched all of the icons remaining. In that case, the program uses a return statement to skip the rest of the method. If the loop gets through all of the labels without executing the return statement, that means that all of the icons on the form were matched. The program shows a MessageBox to congratulate the player on winning, and then calls the form's Close() method to end the game.

  2. Next, have the label's Click event handler call the new CheckForWinner() method. Be sure that your program checks for a winner immediately after it shows the second icon that the player chooses. Look for the line where you set the second chosen icon's color, and then call the CheckForWinner() method right after that, as shown in the following code.

    // If the player gets this far, the timer isn't 
    // running and firstClicked isn't null,  
    // so this must be the second icon the player clicked 
    // Set its color to black
    secondClicked = clickedLabel;
    secondClicked.ForeColor = Color.Black;
    
    // Check to see if the player won
    CheckForWinner();
    
    // If the player clicked two matching icons, keep them  
    // black and reset firstClicked and secondClicked  
    // so the player can click another icon 
    if (firstClicked.Text == secondClicked.Text)
    {
        firstClicked = null;
        secondClicked = null;
        return;
    }
    
  3. Save and run the program. Play the game and match all of the icons. When you win, the program displays a congratulatory MessageBox (as shown in the following picture), and then closes the box.

    Matching game with MessageBox

    Matching game with MessageBox

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