Microsoft Visual C# Example Application: Percentage Conversions

1. Start Microsoft Visual Studio
2. To create a new application, on the main menu, click File -> New Project...
3. In the middle list, click Windows Forms Application
4. Change the Name to PercentageConversions
5. Click OK
6. Design the form as follows: 
    

   Control Text Name TextAlign GroupBox Converting a Percentage to Decimal     Label Value:     TextBox 5 txtPercentage1 Right Label % of     TextBox 10 txtValue1 Right Button = btnConvert1   TextBox   txtValue1 Right GroupBox Converting a Fraction to a Percentage     TextBox 3 txtNumerator Right Label /     TextBox 4 txtDenominator Right Button = btnFractionToPercent   TextBox   txtPercentage2 Right Label %     GroupBox Converting a Decimal to Percentage     Label Value:     TextBox 0.125 txtDecimal1 Right Button = btnDecimalToPercent   TextBox   txtPercentage3 Right Label %     GroupBox Converting a Percentage to Decimal     Label Value:     TextBox 75 txtPercentage4 Right Label %     Button = btnPercentToDecimal   TextBox   txtDecimal2 Right Button Close btnClose

7. Double-click the first = button
8. Implement its event as follows:

   private void btnConvert1_Click_1(object sender, EventArgs e)
   {
       double percent = 0.00;
       double value = 0.00;
       double result;
   
       try
       {
           percent = double.Parse(txtPercentage1.Text);
       }
       catch (FormatException)
       {
           MessageBox.Show("Invalid Percent Value", "Percentage Conversion");
       }
   
       try
       {
           value = double.Parse(txtValue1.Text);
       }
       catch (FormatException)
       {
           MessageBox.Show("Invalid Value to Convert", "Percentage Conversion");
       }
   
       result = percent * value / 100;
       txtResult1.Text = result.ToString("F");
   }

9. Return to the form
10. Double-click the second = button
11. Implement its event as follows:

    private void btnFractionToPercent_Click(object sender, EventArgs e)
    {
        double numerator = 0.00;
        double denominator = 0.00;
        double result;
    
        try
        {
            numerator = double.Parse(txtNumerator.Text);
        }
        catch (FormatException)
        {
            MessageBox.Show("Invalid Numerator", "Percentage Conversion");
        }
    
        try
        {
            denominator = double.Parse(txtDenominator.Text);
        }
        catch (FormatException)
        {
            MessageBox.Show("Invalid Value to Convert", "Percentage Conversion");
        }
    
        result = (numerator / denominator) * 100;
        txtPercentage2.Text = result.ToString("F");
    }

12. Return to the form
13. Double-click the third = button
14. Implement its event as follows:

    private void btnDecimalToPercent_Click(object sender, EventArgs e)
    {
        double value = 0.00;
        double result;
    
        try
        {
            value = double.Parse(txtDecimal1.Text);
        }
        catch (FormatException)
        {
            MessageBox.Show("Invalid Value to Convert", "Percentage Conversion");
        }
    
        result = value * 100;
        txtPercentage3.Text = result.ToString("F");
    }

15. Return to the form
16. Double-click the last = button
17. Implement its event as follows:

    private void btnPercentToDecimal_Click(object sender, EventArgs e)
    {
        double value = 0.00;
        double result;
    
        try
        {
            value = double.Parse(txtPercentage4.Text);
        }
        catch (FormatException)
        {
            MessageBox.Show("Invalid Value to Convert", "Percentage Conversion");
        }
    
        result = value / 100;
        txtDecimal2.Text = result.ToString("F");
    }

18. Return to the form
19. Double-click the Close button
20. Implement its event as follows:

    private void btnClose_Click(object sender, EventArgs e)
    {
        Close();
    }

21. To execute, press F5
     
    
22. Enter some values and click the = buttons
     
    
     
    
23. Close the form and return to the your programming environment

Application