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Add data from a list to a ListBox C#

I have list, listbox, button and a textbox.
My idea is to make that by clicking on the button, the content of the textbox is added to the list, and then pass the data to a listbox.
My problem is, if you add what I write, but the items that are in the listbox are overwritten by the new one that you insert. and I want only more items added. to the list and to go to the listbox. Thank you very much for your answers. This is the code of my button:
private void button54_Click(object sender, RoutedEventArgs e)
{
List<Playlists> List1 = new List<Playlists>();
List1.Add(new Playlists(textBox3.Text, #rutaalbum));
lbListbox.ItemsSource = List1;
}

I am just making a demo stand in for your Playlists class.
ToString has been overridden in order to display some text in the listbox. Without it, you will only display the class name.
ObservableCollection is used instead of List, so that the listbox updates when a new item is added.
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
MyList = new ObservableCollection<Playlists>();
MyListBox.ItemsSource = MyList;
}
private ObservableCollection<Playlists> MyList { get; }
private void Button_Click(object sender, RoutedEventArgs e)
{
MyList.Add(new Playlists(textBox3.Text));
}
}
public class Playlists
{
public Playlists(string title) { Title = title; }
public string Title { get; }
public override string ToString() { return Title; }
}

It seems , you are always creating items with new list. need to add items to existing list.
use below code. it would be useful.
private void button54_Click(object sender, RoutedEventArgs e) {
lbListBox.Items.Add(new Playlists(textBox3.Text, #rutaalbum));
}

How do I get notified when an array property changes?

My class contain many properties and i need to handle each properties.
See this below:
public partial class my_form : Form
{
private Image[] _imagelist;
public Image[] imagelist
{
get
{
return _imagelist;
}
set
{
this._imagelist = value;
this.on_imagelist_changed();
}
}
private void on_imagelist_changed()
{
// do something.
}
private void button1_Click(object sender, EventArgs e)
{
/* set new imagelist */
this.imagelist = getimagelist();
}
}
Yes, It's work fine.
But when i call like this.
public partial class my_form
{
private void listView1_MouseDoubleClick(object sender, MouseEventArgs e)
{
int selectedIndex = this.listView1.SelectedItems[0].ImageIndex;
this.imagelist[selectedIndex] = dosomething(this.imagelist[selectedIndex]);
}
}
It's don't call on_imagelist_changed(). Why ?
I can't add property by indexer like this. :(
public partial class my_form
{
public Image imagelist[int x]
{
get
{
return _imagelist[x];
}
set
{
this._imagelist[x] = value;
this.on_imagelist_changed();
}
}
}
Can anyone help me solve this problem ?
Can i avoid to make a control class like this C# Indexers ?
I founded some suggestion, they told me let try ObservableCollection. I don't understand about this. May be someone example for me ?

It's don't call on_imagelist_changed(). Why?
Because, quite bluntly, imageList has not changed. Some images inside imageList may have changed, but your code reacts only to the change of the entire imageList. The assignment calls get of your property twice; it never calls the setter.
I can't add property by indexer like this.
That's correct. However, you correctly noted that you could use an observable collection:
public ObservableCollection<Image> Images {get;}
private void OnImageListChanged(
object sender
, NotifyCollectionChangedEventArgs e) {
// do something.
}
public MyForm() {
Images = new ObservableCollection<Image>();
Images.CollectionChanged += OnImageListChanged;
}

Because your property gets and sets pointer to array, not array itself. So when you change array items pointer stays the same.
That's why properties should not return arrays.

Adding XML node on the basis of TextBox entry inside WPF Form

Suppose i have created a WPF form having one text box. i am calling that form inside another wpf window's gridpanel and after entering value inside the textbox, i am clicking on submit button. After button click, i need to get that value and save it in string form inside my current class. My logic is something like this.
For getting the from inside my current window:-
void SelectedClick(object sender, RoutedPropertyChangedEventArgs<object> e)
{
selectedItem.ContextMenu = VcontextMenu;
VcontextMenu.Items.Add(VmenuItem1);
VmenuItem1.Click += AddValidation;
details();
}
void AddValidation(object sender, RoutedEventArgs e)
{
ValidationForm obj = new ValidationForm();
ProcessGrid.Content = obj.VForm;
}
Now i want to store the value of my textbox inside a string. For that i have used following code:-
public void details()
{
ValidationForm obj = new ValidationForm();
string str = obj.s.ToString();
}
My ValidationForm Code:-
public partial class ValidationForm : UserControl
{
public string s { get; set; }
public ValidationForm()
{
InitializeComponent();
}
public void XSave_Click(object sender, RoutedEventArgs e)
{
s = TextValidationName.Text;
}
}
but instead of opening the form, the control is going to obj.s.ToString() and showing error as "Object reference not set to an instance of an object." Please help. Thanks.

The issue is caused since the string s in your ValidationForm class is not assigned. It is probably caused since the XSave_Click() method is not being called.
Ensure that you properly assign the value to s before you try to get value from it.

How to pass data in combo box in one form to the gridview in another form in windows application using C#.net

I have a gridview in one form and a combo box in another form.If i select a value in the combo box that value should be passed to the gridview.how can i achieve this...

Your question has too few details, but as a suggestion I'll try to put some code and maybe it'll give you some hint.
// In case if you're dealing with WinForms
// For WPF solution could have similar approach
public class DataGridForm : Form
{
private DataGrid _grid;
public DataGridForm()
{
InitializeComponent();// <-- here _grid is instantiated
}
public void LoadData(object data)
{
// load data into grid
// I don't know, could be smt like
DataGridCell cell = _grid.Cells[0,0];
cell.Value = data;
}
}
public class FormWithComboBox : Form
{
private ComboBox _comboBox;
public DataGridForm DataGridForm { get; set; }// value is set by some externat user
public FormWithComboBox()
{
InitializeComponent();// <-- here _grid is instantiated
// including handler for OnSelectedItemChanged event
}
private void _comboBox_OnSelectedItemChanged(object sender, EventArgs e)
{
DataGridForm.LoadData(_comboBox.SelectedItem);
}
}

Linking a Text Box to a variable?

I would like to have direct access to the text inside a textbox on another form, so I added a public variable _txt to a form and added an event like so:
private void richTextBox1_TextChanged(object sender, EventArgs e)
{
_txt = richTextBox1.Text;
}
But the form is loaded like this:
public FrmTextChild(string text)
{
InitializeComponent();
_txt = text;
richTextBox1.Text = _txt;
Text = "Untitled.txt";
}
Is there a better way to directly link the two?

You could use a property instead to read directly from your TextBox. That way you don't need an extra variable at all.
public string Text
{
get
{
return richTextBox1.Text;
}
}
Add a setter if you also want to be able to change the text.

I don't think you should ever have forms reference each other's controls: when you change the lay out of one you will have to rewrite the code for the other. It is much better IMHO to store shared values in a separate class and have both forms reference that. Like so:
public class DataContainer
{
public string SomeData{get;set;}
}
public class Form1:Form
{
private DataContainer _container;
public Form1(DataContainer container)
{
_container=container;
}
private void richTextBox1_TextChanged(object sender, EventArgs e)
{
_container.SomeData = richTextBox1.Text;
}
private void SpawnForm2()
{
var form2=new Form2(_container);
form2.Show();
}
public class Form2:Form
{
private DataContainer _container;
public Form2(DataContainer container)
{
_container=container;
}
}

Another way to do it would be setting the Modifiers property for the TextBox (or any other control you want to access) to Protected Internal and then open the second form, the Owner being the first form.
This way, you can later on access the control and its properties with something like this:
((Form1)this.Owner).textBox1.Text = "This is a message from the second form";