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Sharing values between different Classes in WPF

I have a WPF Project where I want to save DataRows from a DataGrid into an "options" class and retrieve those variables in another window.
Thats how I save my Variable from my DataGrid into my "options" Class (mainWindow.xaml.cs):
options.title = Convert.ToString((showEntries.SelectedItem as DataRowView).Row["title"]);
This Variable im saving via a getter and setter (options.cs):
public string Title
{
get { return title; }
set { title = value; }
}
And now I want to retrieve the saved variable in another window(updateDatabse.xaml):
private void getUpdateEntries()
{
Options returnValues = new Options();
titleBox.Text = returnValues.Title;
}
My Question is: Why is my textbox "titleBox" empty when running my code.

If the logic of your task does not provide for the creation of several instances of classes (and as far as I understand your explanations, this is so), then you can use the Singlton implementation.
Example:
public class Options
{
private string title;
public string Title
{
get { return title; }
set { title = value; }
}
private Options() { }
public static Options Instance { get; } = new Options();
}
Options.Instance.Title = Convert.ToString((showEntries.SelectedItem as DataRowView).Row["title"]);
private void getUpdateEntries()
{
titleBox.Text = Options.Instance.Title;
}

You mixed things up.
private void getUpdateEntries()
{
Options returnValues = new Options();
returnValues.title = Convert.ToString((showEntries.SelectedItem as DataRowView).Row["title"]);
titleBox.Text = returnValues.Title;
}

How to Output from Generic Array List, to Listbox?

I am trying to output from Array list to a Listbox. My problem is I think is I do not know how to connect the Class to the Generic array list a made? The end result should look like this:
And the information should be then sorted like so: all the information enters the first list box, and then the above 18 goes to adults, and the below 18 to kids. My class looks like this:
namespace Patients
{
public class Person
{
public string Name { get; set; }
public int Age { get; set; }
public String Password { get; set; }
public Person() //Constructor
{
Age = 0;
Password = "";
}
public Person (string name, int age, string password) //Parameters
{
this.Name = name;
this.Age = age;
this.Password = password;
}
public override string ToString() //
{
return Name + Age.ToString() + Password; //outputs as a string
// return Name + " (" + Age + " years) " + Password ;
}
}
}
namespace Patients
{
public partial class WebForm1 : System.Web.UI.Page
{
public static void Page_Load(object sender, EventArgs e)
{
}
public void ButtonAdd_Click(object sender, EventArgs e)
{
Person p = new Person();
List<string> People = new List<string>();
People.Add(TextBoxName.Text);
People.Add(TextBoxAge.Text);
People.Add(TextBoxPassword.Text);
foreach (object Person in People)
{
ListBoxAll.Items.Add(p.Name + p.Age.ToString() + p.Password);
}
if (p.Age > 18)
{
ListBoxAdults.Items.Add(p.Name + p.Age.ToString() + p.Password);
}
else
{
ListBoxKids.Items.Add(p.Name + p.Age.ToString() + p.Password);
}
}
}
}

I think your problem is, that you don't set the Properties. In Fact you don't need a List at all, but you can use a List to keep hold of your patients. It's still not necessary though:
namespace Patients
{
public partial class WebForm1 : System.Web.UI.Page
{
// Define Property and initialize List
public List<Person> patients{ get; } = new List<Person>();
public static void Page_Load(object sender, EventArgs e)
{
}
public void ButtonAdd_Click(object sender, EventArgs e)
{
// Use the Constructor with Parameters
Person p = new Person(TextBoxName.Text, TextBoxAge.Text, TextBoxPassword.Text);
// Add your patient to your List
patients.Add(p);
// Use the ToString() of your Person
ListBoxAll.Items.Add(p.ToString());
if (p.Age > 18)
{
ListBoxAdults.Items.Add(p.ToString());
}
else
{
ListBoxKids.Items.Add(p.ToString());
}
}
}
}

Looks like you are mixing and matching a bit.
Try something like this.
Person p = new Person();
p.Name = TextBoxName.Text;
p.Age= TextBoxAge.Text;
p.Password= TextBoxPassword.Text;
ListBoxAll.Items.Add(p);

A few tricks that are nice to us, first off you can declare defaults for properties like so:
public string Name { get; set; } = "Steve";
public int Age { get; set; } = 1;
public String Password { get; set; } = "password";
However, it should also be noted that "" is the default for strings already and 0 is the default for non-nullable int, so you don't even need to worrying about those default values.
Declaring Age = 0; in the constructor is basically a waste of time in this case. (If it was a nullable int however the default is null)
Next up, since you are okay with defaults, you don't need to declare properties in the constructor like you are.
You can completely remove the constructor and just do the following:
var myPerson = new Person { Name = "Steve", Age = 18, Password = "Foo" };
Next up, you are losing all your existing people as soon as you exit the scope of the button click.
Instead you'll want to declare two lists of people outside the scope of the click method (that way they persist), something like "Adults" and "Children"
Then perhaps make a method called "PopulateLists" that would do the following:
Clear all list boxes
Add to each box the list of each groups names that apply (you can make an IQueryable by using Linq and Select statements on your list)
When you click the button, you should make a new person, assign it to the right list, then call PopulateLists()
Here's the info you need to get started:
Linq selection to get list of properties (in this case Im going to turn a List of People into a List of Ages, you can do the same with names though)
var ages = People.Select(p => p.Age);
The .Items property of a ListBox works the same as a list, it just visually shows itself. It's a list of strings specifically.
So for example you can do things like...
MyListBox.Items.Clear();
MyListBox.Items.Add(...);
MyListBox.Items.AddRange(...);
etc etc.
That should get you started!

C# - How to use Dictionaries with GUI

I'm struggling to understand how a user can add a value to a dictionary with the use of a GUI.
I've managed to do this with the use of a list:
List<Person> clients = new List<Person>();
Person x = new Person();
x.Name = nameTextbox.text;
x.Address = addressTextbox.Text;
clients.Add(x);
public void AddClientButton_Click(object sender, EventArgs e)
{
Class Person{
public string Name{
get {return Name}
value { name = value;}
public string Address{
get {return Address}
value { name = Address;}
}
}
I've just typed this out as I'm not on my Windows machine (so forgive me so any mistakes), but none-the-less it works. However, I'm required to use a Dictionary due to the fact it has a Key & Value.
Everyone seems to add the data themselves and within a ConsoleApplication, I'm required to let the User add the data with the use of a GUI. I was wondering if the concept is similar with the use of a Dictionary or are they worlds apart?
Dictionary<string, string> clients = new Dictionary<string, string();
Person x = new Person();
x.Name = nameTextbox.text;
x.Address = addressTextbox.Text;
clients.Add(x);
public void AddClientButton_Click(object sender, EventArgs e)
{
Class Person{
public string Name{
get {return Name}
value { name = value;}
public string Address{
get {return Address}
value { name = Address;}
}
}
Could someone please point me in the right direction, possibly with the use of an example so I can grasp the concept.
Thank you.

Assuming the name of the person is unique
Dictionary<string, Person> clients = new Dictionary<string, Person>();
....
public void AddClientButton_Click(object sender, EventArgs e)
{
Person x = new Person();
x.Name = nameTextbox.text;
x.Address = addressTextbox.Text;
clients.Add(x.Name, x); //Beware, if the name is not unique an exception will be thrown.
}

c# property won't work?

hello guys i have a form... and i set my properties if the user will click the submit button and after then i will call my add_data function which contains my database query...but the problem is the properties I've set in my form will become empty in my add_data function...why this is happening?
actually i already try adding a messagebox in my form which contains the data in my properties after setting my properties value and it works fine but when i add it to my databasecon class the messagebox shows null... i try also putting my properties and database query function in the same class and it's working but what i want is to separate my properties and my database query functions...
this is the codes in my properties
class persons
{
//person attributes
private string fname;
private string lname;
private string age;
private string gnder;
private string address;
//initialize
public persons()
{
this.fname = "";
this.lname = "";
this.age = "";
this.gnder = "";
this.address = "";
}
//set and get properties
public string p_fname
{
get { return this.fname; }
set { this.fname = value; }
}
public string p_lname
{
get { return this.lname; }
set { this.lname = value; }
}
public string p_age
{
get { return this.age; }
set { this.age = value; }
}
public string p_gender
{
get { return this.gnder; }
set { this.gnder = value; }
}
public string p_address
{
get { return this.address; }
set { this.address = value; }
}
}
this is the codes in my form
public partial class add : Form
{
persons p = new persons();
databasecon d = new databasecon();
private void addbtn_Click(object sender, EventArgs e)
{
p.p_fname = this.fname.Text;
p.p_lname = this.lname.Text;
p.p_age = this.age.Text;
p.p_gender = this.gender.Text;
p.p_address = this.address.Text;
d.add_data();
this.Close();
}
}
and this is the codes in my database connection and queries
class databasecon
{
OleDbConnection con = new OleDbConnection();
persons p = new persons();
public databasecon()
{
con.ConnectionString = "Provider=Microsoft.JET.OLEDB.4.0;Data Source=../dbsample.mdb";
}
public void add_data()
{
try
{
con.Open();
OleDbCommand cmd = new OleDbCommand();
cmd.Connection = con;
cmd.CommandType = CommandType.Text;
cmd.CommandText = "INSERT INTO person(u_fname,u_lname,u_age,u_gender,u_address)VALUES('" + p.p_fname + "','" + p.p_lname + "','" + p.p_age + "','" + p.p_gender + "','" + p.p_address + "')";
cmd.Parameters.AddWithValue("u_fname", p.p_fname);
cmd.Parameters.AddWithValue("u_lname", p.p_lname);
cmd.Parameters.AddWithValue("u_age", p.p_age);
cmd.Parameters.AddWithValue("u_gender", p.p_gender);
cmd.Parameters.AddWithValue("u_address", p.p_address);
cmd.ExecuteNonQuery();
}
catch (Exception e)
{
MessageBox.Show("Error : " + e);
}
finally
{
con.Close();
MessageBox.Show("New person has been successfully added.");
}
}
}

You need to pass p as a parameter to the add_data method.
public void add_data(persons person)
then call it with the parameter:
d.add_data(p);
and use the properties of person in the method:
cmd.Parameters.AddWithValue("u_fname", person.p_fname);
cmd.Parameters.AddWithValue("u_lname", person.p_lname);
cmd.Parameters.AddWithValue("u_age", person.p_age);
cmd.Parameters.AddWithValue("u_gender", person.p_gender);
cmd.Parameters.AddWithValue("u_address", person.p_address);

you create databasecon() in form and then call add_data method and you don't pass 'persons' instance. in databasecon you use persons istnace which is field in this class. you soudl add parameter do add_data method and pass instance or 'persons' you want to save and use it in command

Your p fields in your add and databasecon classes are separate. When you call d.add_data(), the d object can only see its instance of persons p ....
To fix this, pass the persons object into the add_data method.
class databasecon{
// Remove this line, we pass it into the function below
/* persons p = new persons(); */
public void add_data(persons p){
try{
// same code as before
}catch(Exception e){
// same code
}
finally{
// same
}
}
}

You have an instance of Person class which you fill and then use an instance of databasecon which is completely not conntected to the person class you filled.
Change add_data() to
public void add_data(person p) { ... }
this will use the properties from p passed as parameter.
You call it like this
d.add_data(p);
Except for that have a look at some C# for begginers book.

Overlooking the fact that your code is extremely poorly written.
You are not passing in the persons class that you created.
Something like
public void add_data(persons p) {//..blah}
Then
private void addbtn_Click(object sender, EventArgs e) {
p.p_fname = this.fname.Text;
p.p_lname = this.lname.Text;
p.p_age = this.age.Text;
p.p_gender = this.gender.Text;
p.p_address = this.address.Text;
d.add_data(p);
this.Close();
}

From what I can see in the code above, you call add_data from your databasecon class, which has an instance p of Person. Since you are not passing a Person object to your add_data method, the empty, unset p object is what is being saved to the database.
Adding a Person parameter to add_data and use that when saving the data to the database.

There are several things I don't like in your code.
Let's start however with your specific problem:
Your code contains also a source of security issues and malignous SQL code injection.
You are saving always an empty person and there is a problem with your SQL connection string.
Try this code instead.
private void addbtn_Click(object sender, EventArgs e)
{
try
{
persons p = new persons(); // we use a new instance of person class
p.p_fname = this.fname.Text;
p.p_lname = this.lname.Text;
p.p_age = this.age.Text;
p.p_gender = this.gender.Text;
p.p_address = this.address.Text;
d.add_data(p); // we save the instance of persons
this.Close();
}
catch (Exception ex)
{
MessageBox.Show("Error : " + e);
}
}
...
class databasecon
{
public void add_data(person p) // we need a person as parameter
{
OleDbConnection con = new OleDbConnection();
con.ConnectionString = "Provider=Microsoft.JET.OLEDB.4.0;Data Source=../dbsample.mdb";
con.Open();
try
{
OleDbCommand cmd = new OleDbCommand();
cmd.Connection = con;
cmd.CommandType = CommandType.Text;
// this is the correct sql command string
cmd.CommandText = "INSERT INTO person(u_fname,u_lname,u_age,u_gender,u_address) " +
VALUES (#u_fname, #u_lname, #u_age, #u_gender, #u_address)";
cmd.Parameters.AddWithValue("u_fname", p.p_fname);
cmd.Parameters.AddWithValue("u_lname", p.p_lname);
cmd.Parameters.AddWithValue("u_age", p.p_age);
cmd.Parameters.AddWithValue("u_gender", p.p_gender);
cmd.Parameters.AddWithValue("u_address", p.p_address);
cmd.ExecuteNonQuery();
}
finally
{
con.Close();
}
}
...
}
Now let's talk about code style.
Is a good thing to use CamelCase style in your code, look on the web about C# CamelCase:
Classes and properties should all start with a capitalized letter.
Your class express a single person not a list of persons so its name should be public class Person.
Avoid the use achronims or of short names when you can...
p_lname should be LastName, people will thanks you if you make your code more readable, C# is not C and C# is not PHP!
A field or a property with a longer name will not consume more memory than a property with a short and unreadable name :)
Use always strong typing... age is not a string, age is an integer.
The property should be public int Age, not a string!
Never use MessageBox in your non-visual classes.
Try to catch for exceptions in your client code, not in your library code!

I dont know if I 100% understand the issue about I guess it's because your inserting an empty persons class into the db.
Your `add_data method should take a person object like so.
public void add_data(persons obj)
{
p = obj;

you must pass person object to add_data method
public void add_data(persons p)
{
...
}
and call it:
d.add_data(p);

Why does this not work?

I have a class which will act as variables to store data from textboxes:
public class Business
{
Int64 _businessID = new Int64();
int _businessNo = new int();
string _businessName;
string _businessDescription;
public Int64 BusinessID
{
get { return Convert.ToInt64(_businessID.ToString()); }
}
public int BusinessNo
{
get { return _businessNo; }
set { _businessNo = value; }
}
public string BusinessName
{
get { return _businessName; }
set { _businessName = value; }
}
public string BusinessDescription
{
get { return _businessDescription; }
set { _businessDescription = value; }
}
I then have the code to store the data from the textbox into a session and into a list (there can be many businesses uploaded to the database at one time) - database irrelevent for now. I then want to display the list of businesses stored into the session onto the gridview: (b = class business)
List<Business> businessCollection = new List<Business>();
protected List<Business> GetBusinesses()
{
return (List<Business>)Session["Business"];
}
protected void btnRow_Click(object sender, EventArgs e)
{
if (Session["Business"] != null)
businessCollection = (List<Business>)Session["Business"];
Business b = new Business();
b.BusinessNo = Convert.ToInt32(txtBNo.Text);
b.BusinessName = txtBName.Text;
b.BusinessDescription = txtBDesc.Text;
businessCollection.Add(b);
GridView1.DataSource = GetBusiness();
GridView1.DataBind();
}
It doesn't seem to add the list to the gridview, can someone help?

Debug your code and ensure that if (Session["Business"] != null) actually evaluates to true.
If it is false then you are adding to a list that is never returned from GetBusinesss
Without any more information you can rewrite it like this:
List<Business> businessCollection = new List<Business>();
protected List<Business> GetBusinesses()
{
if (Session["Business"] == null)
return businessCollection;
else
return (List<Business>)Session["Business"];
}
protected void btnRow_Click(object sender, EventArgs e)
{
Business b = new Business();
b.BusinessNo = Convert.ToInt32(txtBNo.Text);
b.BusinessName = txtBName.Text;
b.BusinessDescription = txtBDesc.Text;
var currentCollection = GetBusinesses();
currentCollection.Add(b);
GridView1.DataSource = currentCollection;
GridView1.DataBind();
}
I personally wouldn't do it like this, as it seems like you need an assignment to Session["Business"] but I don't want to change the logic of your code.
Update
I wanted to update this with what I think you wanted to accomplish.
protected List<Business> GetBusinesses()
{
if (Session["Business"] == null)
Session["Business"] = new List<Business>();
return (List<Business>)Session["Business"];
}
protected void btnRow_Click(object sender, EventArgs e)
{
Business b = new Business();
b.BusinessNo = Convert.ToInt32(txtBNo.Text);
b.BusinessName = txtBName.Text;
b.BusinessDescription = txtBDesc.Text;
var currentCollection = GetBusinesses();
currentCollection.Add(b);
GridView1.DataSource = currentCollection;
GridView1.DataBind();
}

It seems you are not assigning anything to Session["Business"]

There's a very strong chance that you're problem is caused by the fact that you are referencing the Business List object inconsistently. You've created an accessor for this object, so use it everywhere.
This:
if (Session["Business"] != null)
businessCollection = (List<Business>)Session["Business"];
Should be:
var businessCollection = GetBusiness();
Note the use of var: I suspect defining businessCollection as a member variable is part of the problem. In any case it is bad design if your intent is to store the list in the session. So I would also remove the member declaration for businessCollection and stick with a locally scoped variable.