Mileage WPF (Evening)

Here is the Mileage class

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace MileageForm
{
    /// 

    /// this is a very simple mileage class 
    /// it has three properties
    /// Distance, Gallons and PricePerGallon
    /// I used a short cut method to create
    /// the properties just expressing the get and set
    /// It has two methods one to calculate 
    /// the gas mileage and one to calculate the 
    /// price per mile
    /// 
    class Mileage
    {
        //short cut for properties
         public double Distance {get; set;}
         public double Gallons { get; set; }
         public double PricePerGallon { get; set; }

        //methods
        public double CalculateMileage()
         {
             return Distance / Gallons;
         }

        public double CalculatePricePerMile()
        {
            return  PricePerGallon * Gallons /Distance;
        }

    } 
}

Here is the XAML for the form

<Window x:Class="MileageForm.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525"
        Name="Form1">
    <Grid x:Name="labelCost">
        <Label Content="Enter the miles traveled" HorizontalAlignment="Left" Margin="46,7,0,0" VerticalAlignment="Top"/>
        <TextBox x:Name="textMiles" HorizontalAlignment="Left" Height="23" Margin="227,11,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="120"/>
        <Label Content="Enter the total gallons" HorizontalAlignment="Left" Margin="46,55,0,0" VerticalAlignment="Top"/>
        <TextBox x:Name="textGallons" HorizontalAlignment="Left" Height="23" Margin="227,55,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="120"/>
        <Label Content="Enter the price per Gallon" HorizontalAlignment="Left" Margin="46,98,0,0" VerticalAlignment="Top"/>
        <TextBox x:Name="textPrice" HorizontalAlignment="Left" Height="23" Margin="227,98,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="120"/>
        <Button x:Name="ButtonCalculate" Content="Calculate" HorizontalAlignment="Left" Margin="56,142,0,0" VerticalAlignment="Top" Width="75" Click="ButtonCalculate_Click"/>
        <Label Content="Your Mileage is" HorizontalAlignment="Left" Margin="46,181,0,0" VerticalAlignment="Top"/>
        <Label x:Name="labelMileage" Content="Label" HorizontalAlignment="Left" Margin="227,181,0,0" VerticalAlignment="Top" RenderTransformOrigin="0.474,-0.385"/>
        <Label Content="The cost per mile is" HorizontalAlignment="Left" Margin="46,212,0,0" VerticalAlignment="Top"/>
        <Label x:Name="labelCost1" Content="Label" HorizontalAlignment="Left" Margin="227,220,0,0" VerticalAlignment="Top" RenderTransformOrigin="-0.026,0.385"/>
        <Button x:Name="buttonClear" Content="Clear" HorizontalAlignment="Left" Margin="56,259,0,0" VerticalAlignment="Top" Width="75" Click="buttonClear_Click"/>
        <Button x:Name="buttonExit" Content="Exit" HorizontalAlignment="Left" Margin="156,259,0,0" VerticalAlignment="Top" Width="75" Click="buttonExit_Click"/>

    </Grid>
</Window>

Here is the code behind the form

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace MileageForm
{
    /// 

    /// Interaction logic for MainWindow.xaml
    /// this is the code behind the windows form
    /// 
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            //initilize the form--don't remove thos
            InitializeComponent();
        }

        private void ButtonCalculate_Click(object sender, RoutedEventArgs e)
        {

            //call the method to make sure the text boxes have content
            //they return true if there is a value missing
            bool good =CheckTextBoxes();
            //if there is a value missing stop the action
            //here
            if (good)
            {
                return;
            }
            //delcare a new instance of Mileage class
            Mileage m = new Mileage();
            //get inputs
            m.Distance = double.Parse(textMiles.Text);
            m.Gallons = double.Parse(textGallons.Text);
            m.PricePerGallon = double.Parse(textPrice.Text);
            //outputs
            labelMileage.Content = m.CalculateMileage().ToString();
            EvaluateMileage(m.CalculateMileage());
            labelCost1.Content= m.CalculatePricePerMile().ToString("C");

        }

        private void buttonClear_Click(object sender, RoutedEventArgs e)
        {
            //this method clears the textboxes and labels
            textMiles.Clear();
            textGallons.Clear();
            textPrice.Clear();
            labelCost1.Content="";
            labelMileage.Content = "";
            //resets the color to white
            Form1.Background = new SolidColorBrush(Colors.White);
            textMiles.Focus();
        }

        private void buttonExit_Click(object sender, RoutedEventArgs e)
        {
            //close the form
            this.Close();
            
        }

        private void EvaluateMileage(double mileage)
        {
            //this checks the mileage and returns a 
            //background color based on the value
            if (mileage > 35)
            {
                Form1.Background = new SolidColorBrush(Colors.Green);
            }
            else if (mileage > 25)
            {
                Form1.Background = new SolidColorBrush(Colors.Yellow);
            }
            else
            {
                Form1.Background = new SolidColorBrush(Colors.Red);
            }
        }

        private bool CheckTextBoxes()
        {
           //this method checks to make sure the form
            //textboxes have values
            if (textMiles.Text=="")
            {
                MessageBox.Show("Enter a valid mileage");
                return true;
            }
            if(textGallons.Text=="")
            {
                MessageBox.Show("Enter a valid Gallon amount");
               return true;
            }
            if (textPrice.Text == "")
            {
                MessageBox.Show("Enter a valid Price per Gallon");
                return true;
            }
            return false;
        }
    }
}

Here is a picture of the form in design

File Input and Output (Evening)

Here is the WriteFile class

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO; //necessary for file creation
//and reading

namespace FileHandling
{
    class WriteFiles
    {
        /// <summary>
        /// This class writes a text file
        /// the constructor takes the path
        /// --the complete file name--
        /// and instantiates the StreamWriter
        /// object that writes the files
        /// </summary>
        private StreamWriter writer;
        public WriteFiles(string path)
        {
            //instantiate the SteamWriteObject
            //its constructor takes the path
            //the true means set the file to append
            //if it exists. If it doesn't exist it
            //will create the file
            //false would mean to write over
            //the file if it exists
            writer = new StreamWriter(path, true);
        }

        public void AddToFile(string line)
        {
            //this uses a method of the StreamWriter
            //that writes a line to the file
            writer.WriteLine(line);
        }

        public void CloseFile()
        {
            //this closes the file
            //if you don't close it
            //you will be unable to access
            //the file
            writer.Close();
        }
    }
}

---

Here is the ReadFile class

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;//nescessary for file IO

namespace FileHandling
{
    
    class ReadFile
    {
        /// <summary>
        /// this class reads text files.
        /// It takes the path to the file as a parameter
        /// in the constructor
        /// </summary>
        /// 
        private StreamReader reader;
        private string filePath;

        //constructor takes in the path
        //as parameter
        public ReadFile (string path)
        {
            filePath = path;
           
        }

        public string GetFile()
        {
            //this method gets the file and
            //reads it, returning a string
            string line = null;
            //when dealing with things like files
            //it is a good idea to use a try set
            //It is always possible that the file
            //is not at the specified path
            //or that it is unreadable
            try 
            {
                //get the file from the location
                //indicated by the path
                reader = new StreamReader(filePath);
                //read it all into a string
                //this is not very sophisticated
                //there are other ways to read the file
                line = reader.ReadToEnd();
            }
            catch (FileNotFoundException fnf)
            {
                //the FileNotFoundException is a pre built
                //exception for missing files
                //we throw the exception to the 
                //calling class for display
                throw fnf;
            }
            catch (Exception ex)
            {
                //this catch is for any other kind
                //of error
                throw ex;
            }
            return line;
        }
    }
}

---

Here is the Program class

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace FileHandling
{
    class Program
    {
        /// <summary>
        /// I use this class to call the other classes
        /// The WriteStuff() method writes a file
        /// and the ReadStuff() method reads the
        /// file that was just written
        /// </summary>
        /// 
        static void Main(string[] args)
        {
            Program p = new Program();
            p.WriteStuff();
            p.ReadStuff();
           
            Console.ReadKey();
        }

        private void WriteStuff()
        {
            //instantiate WriteFiles and pass the path
            //to its constructor
            WriteFiles write = new WriteFiles(@"C:\temp\MyFile.txt");
            //write something to store in the file
            Console.WriteLine("Enter whatever");
            string stuff = Console.ReadLine();
            //pass what you write to the WriteFiles method AddToFile(string)
            write.AddToFile(stuff);
            //make sure to close the file
            write.CloseFile();
        }

        private void ReadStuff()
        {
            //this try catch will catch the errors
            //thrown by ReadFiles
            try
            { 
                //first we read the file. If it doesn't exist
                //it will throw a file not found exception
                ReadFile read = new ReadFile(@"C:\temp\MyFile.txt");
                //now we read the file into a string
                string myText = read.GetFile();
                //then we display the string
                Console.WriteLine(myText);
            }
            catch(Exception ex)
            {
                //this catches any error and displays
                //the error message
                Console.WriteLine(ex.Message);
                Console.ReadKey();
            }
        }
    }
}

SQL Examples

Use CommunityAssist
/*
this is a multiline comment
This is a basic SQL 
tutorial
*/
--these are simple selects
--the * is a wild card meaning list all columns
Select * From Person

--choose the columns to display
Select PersonLastName, PersonUserName From Person

--sort by lastname ascending
Select PersonLastName, PersonUserName From Person
order by PersonLastName;

--sort by last name descending and user name ascending
Select PersonLastName, PersonUserName From Person
order by PersonLastName desc, PersonUserName;

--this shows using math in the select clause
Select DonationAmount, DonationAmount+ 100 AS Added
From Donation
order by DonationAmount desc

--you can use these operators with numeric
--or date values
-- <, >, <=, >=, =, !=, <>, Not =
Select DonationDate, DonationAmount From Donation
Where DonationAmount < 100

--with AND
Select DonationDate, DonationAmount From Donation
Where DonationAmount > 100 and DonationAmount < 1000

--with Between
Select DonationDate, DonationAmount From Donation
Where DonationAmount between 100 and 1000

--Between with dates
Select DonationDate, DonationAmount From Donation
Where DonationDate between '9/1/2013' and '9/30/2013'

--OR
Select * from PersonAddress
Where City = 'Bellevue' or City = 'Redmond'

--Like with wildcard. % is for any number of characters
-- _ is for a single character
--the following returns all names starting with t
--and ending with r
Select PersonLastName from Person
Where PersonLastName like 'T%r'

--joining two tables also looking for not null values
--nulls must be addressed using is or is not
--you cannot use comparitive values (=, <, > etc) with nulls
Select PersonFirstName, PersonLastName, Street,Apartment, [State], City, Zip
From Person
inner join PersonAddress
on Person.PersonKey=PersonAddress.PersonKey
Where Apartment is not null

--insert into a table 
Insert into Person (PersonLastName, PersonFirstName)
Values ('Bender','Robot')

--inner joins always return matched values
--outer joins return unmatched values
Select PersonlastName, Street, Apartment, [State], City, Zip
From Person
left outer join PersonAddress
on Person.PersonKey = PersonAddress.Personkey
Where PersonAddress.Personkey is null

-- an inner join with multiple tables
Select PersonFirstName, PersonLastName, Street,Apartment, [State], City, Zip,
ContactInfo, contactTypeName
From Person
inner join PersonAddress
on Person.PersonKey=PersonAddress.PersonKey
inner Join PersonContact
on Person.Personkey=PersonContact.PersonKey
inner join ContactType
on ContactType.ContactTypeKey=PersonContact.ContactTypeKey
Where not City = 'Seattle'
Order by City

--insert. You can only insert into one table at a time
Insert into Person(PersonLastName, PersonFirstName, PersonUsername, 
PersonPlainPassword,PersonEntryDate)
Values ('Conger','Steve','steve@spconger.com','password',getDate())

--insert  the Ident_current function returns the last 
--autonumber generated in the table listed
--it only works with autonumbers
Insert into PersonAddress(Street, Apartment, State, City, Zip, PersonKey)
values('1701 Broadway',null,'Wa','Seattle','98122', IDENT_CURRENT('Person'))

--you can insert multiple rows at a time
--as long as they are in the same table
Insert into Person(PersonLastName, PersonFirstName)
Values('Flanders', 'Ned'),
('Clown','Krusty'),
('Simpson','Homer')

--updates change existing data
--they should always (almost always)
--have a where clause
--Update is the most dangerous
--command in SQL
Update PersonAddress
Set Apartment='3176b',
State='WA'
Where PersonKey=128



Select * From PersonAddress where PersonKey=128

--to be safe with updates and deletes
--you can manually set the beginning and
--ending of a transaction
--this locks the table for the duration
Begin tran

--will set every last name to smith
Update Person
Set PersonLastName='Smith'

Select * From Person

--rollback undoes the command
--commit writes it 
Rollback tran
commit tran

--Delete removes a row or rows from
--a table
--you cannot delete a row that has 
--children in another table
Delete from person
Where PersonKey =128

Square Footage Class Examples (Morming)

Here is the SquareFootage class

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ClassExampleMorning
{
    class SquareFootage
    {
        /************************
         * this class calculates square footage and
         * the total cost of that footage
         * *****************************/


        //fields--class level variables that describe the object
        private double length;
        private double width;
        private double pricePerSquareFoot;

        //this is a default constructor
        //constructors initialize a class
        //setting default values for variables
        //and maybe calling a method
        public SquareFootage()
        {
            Length = 0;
            Width = 1;
            PricePerSquareFoot = 0;
        }

        //this is an overloaded constructor.
        //You can only initialize a class one way
        //but you can set up choices for how
        //to initialize the class
        //In this case you can pass the width and length
        //directly to the constructor
        public SquareFootage(double width, double length)
        {
            Width = width;
            Length = length;
            PricePerSquareFoot = 0;
        }

        //public properties
        //properties expose the private variables
        //to the world
        public double PricePerSquareFoot
        {
            //return lets another class see the value of the field
            get { return pricePerSquareFoot; }
            //set lets another class change the value of the field
            set { pricePerSquareFoot = value; }
        }


        public double Width
        {
            //you can do some validation in a property
            get { return width; }
            set { 
                if (value >0)
                { 
                width = value;
                }
                else
                {
                    //an exception is an error object
                    //here we make our own error with a message
                    Exception ex = new Exception("Must be greater than zero");
                    //we don't have a way to display it here
                    //so we throw it back to the class
                    //where it was called
                    throw ex;
                }
            }
        }
       

        //properties
        public double Length
        {
            get { return length; }
            set { length = value; }
        }

        //public methods
        //these are just methods 
        //just like any other method
        public double CalculateSquareFootage()
        {
            return Width * Length;
        }

        public double CalculateTotalCost()
        {
            return CalculateSquareFootage() * PricePerSquareFoot;
        }
    }
}

---

Here is the Display class

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ClassExampleMorning
{
    class Display
    {
        //Square footage is a class level field
        private SquareFootage sf;

        //the constructor calls the methods
        //for getting inputs and showing outputs
        public Display()
        {
            //I commented this to use the 
            //overloaded constructor in SquareFootage
            //sf = new SquareFootage();
            GetInputs();
            ShowOutputs();
        }

        private void GetInputs()
        {
            //I declare these two variables to
            //store the input, then I pass them
            //to SquareFootage through its 2nd constructor
            double w, l; 
            //the try "tries" all the code. If there is an error
            //it falls to the catch
            try
            {
                Console.WriteLine("Enter the Width");
                //sf.Width = double.Parse(Console.ReadLine());
                w = double.Parse(Console.ReadLine());
                Console.WriteLine("Enter the Length");
                //sf.Length = double.Parse(Console.ReadLine());
                l = double.Parse(Console.ReadLine());
                //initialize SquareFootage and pass it width and length
                sf = new SquareFootage(w, l);

                //but we use the property to assign
                //the value to PricePerSquareFoot
                Console.WriteLine("Enter the Price per square foot");
                sf.PricePerSquareFoot = double.Parse(Console.ReadLine());
            }
            catch(Exception ex)
            {
                //display the error message
                Console.WriteLine(ex.Message);
                Console.ReadKey();
            }
        }

        private void ShowOutputs()
        {
            //call the methods from squareFootage
            //and display the results
            Console.WriteLine("the Square footage is " +
                sf.CalculateSquareFootage());
            Console.WriteLine("the total cost is " +
                sf.CalculateTotalCost());
            Console.ReadKey();
        }

    }
}

---

Here is the Program class

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ClassExampleMorning
{
    class Program
    {
        static void Main(string[] args)
        {
            //this initilizes the Display class
            //and class the constructor
            //that calls the getInputs method
            Display d = new Display();
            
        }
    }


}

Batting Average class Examples(Evening)

Here is the BattingAverage class

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace BattingAverageCalculator
{
    class BattingAverage
    {
        //fields
        private int hits;
        private int atBats;
     

        //public properties for the fields
        public int AtBats
        {
            //the get returns the value of the field
            //lets the calling class see it
            get { return atBats; }
            //the set lets the calling class
            //change the value of the underlying field
            //value is a built in variable
            set { atBats = value; }
        }
        public int Hits
        {
            get { return hits; }
            set { hits = value; }
        }

        public double CalculateBattingAverage()
        {
            //this method calculates the Batting Average
            return ((double)Hits / AtBats) * 1000;
           
        }
        



    }
}

---

Here is the Display class

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace BattingAverageCalculator
{
    class Display
    {
        //declare the BattingAverage Calss
        private BattingAverage ba; 

        //this is the constructor
        //it is called when the class 
        //is made new
        public Display()
        {
            //instantiate (load into memory) 
            //the BattingAverage class
            //
            ba= new BattingAverage();
            //call the GetInput() method
            GetInput();
        }
        private void GetInput()
        {
            //Get the input
            Console.WriteLine("Enter the total at bats");
            //assign the input to the set of the AtBats
            //Property in the BattingAverage class
            ba.AtBats = int.Parse(Console.ReadLine());

            //do the same for the Hits property
            Console.WriteLine("Enter the total hits");
            ba.Hits = int.Parse(Console.ReadLine());

            //call the ShowBattingAVerageMethod
            ShowBattingAverage();

        }

        private void ShowBattingAverage()
        {
            //display the Batting average by calling
            //the CalculateBattingAverage() method
            //in BattingAverage (ba)
            Console.WriteLine("The batting average is " 
                + ba.CalculateBattingAverage());

            
        }
    }
}

---

Here is the Program

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace BattingAverageCalculator
{
    /********************
     * The program class contains the main
     * It really should do nothing
     * but call the class that starts the program
     * *******************/
    class Program
    {
        static void Main(string[] args)
        {
            //Call the display Class (runs the constructor)
            Display d = new Display();
            Console.ReadKey();
        }
    }

}

First Class Example (Evening)

Here is the Mileage Class

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ClassExamples
{
    //fields --class level variables that describe the class
    //properties--make field accessible
    //methods--what the class does
    //constructors--initializing the class

 

    class Mileage
    {
        /************************
         * this class calcuates simple mileage
         * it is more work that you need 
         * for such a simple calulation but it shows
         * the basic parts and concepts of a class
        ***************************/
        //private fields 
        private double gallons;
        private double miles;

        //we have two constructors
        //constructors are methods that
        //initialize the class
        //you can have as many constructors
        //as make sense as long as they
        //have distinct signatures
        //you can only initialize a class
        //one way at a time, so a user
        //has to decide which constructor
        //to invoke
        public Mileage()
        {
            //initialize values
            Miles = 0;
            gallons = 1;
        }
        //overloaded constructor that takes two arguments
         public Mileage(double miles, double gallons)
        {
             //initialize values to what has been passed in
             //through the constructor's parameters
            Miles = miles;
            Gallons = gallons;
        }
        //public properties. A property "encapsulates"
        //a private field and exposes it to other
        //classes to see or change
        public double Miles
        {
            //lets the user see the value
            get { return miles; } 
            //lets the user change the value
            set { miles = value; }
        }

        public double Gallons
        {
            set 
            { 
                //one can do validation in a property
                if(value <=0)
                {
                    //an exception is an error message
                    //we can create our own
                    //because there is no way to display
                    //the error message in this class
                    //we throw it back to where the set
                    //message is called--in our case
                    //the Main() method in Program
                    Exception ex = new Exception("Enter a valid number for gallons");
                    throw ex;
                }
                else { 
                    //if the value is good just assign it to the field
                gallons = value;
                }
            }
            get { return gallons; }
        }

        //public method
        public double CalculateGasMileage()
        {
            return Miles / Gallons;
        }

    }
}

Here is the Program class

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ClassExamples
{
    class Program
    {
        static void Main(string[] args)
        {
            //try catches "try" all the code. When they encounter
            //an error they fall immediately to the catch
            //skipping any lines after the error.
           try
            {
            Console.WriteLine("Enter the Miles traveled");
            double miles = double.Parse(Console.ReadLine());
            Console.WriteLine("Enter the gallons");
            
                double gallons = double.Parse(Console.ReadLine());
               //this uses the overloaded constructor of Mileage
                Mileage mileage = new Mileage(miles, gallons);
               //we call the CalculateGasMileage method
               //of the MileageClass
                Console.WriteLine("You MPG is " + mileage.CalculateGasMileage().ToString());
            }
            catch(Exception ex)
            {
                //this is a general catch. It will catch any error message 
                //and display the error object's message
                //you can do more that display error messages in a catch
                //You can redirect the code or do things to manage
                //the error
                Console.WriteLine(ex.Message);
                Console.ReadKey();
                return;
            }

           
            Console.ReadKey();
        }
    }
}