从另一个WPF窗口将项目添加到列表框

Question

so I have my MainWindow that contains a list box menu_listbox and a button Add_menu_item that when clicked will open a second wpf window New_menu_item in which I have texboxes and a button Add_new_menu_item when the butoon is clicked it will close the New_menu_item window and add the values to the class new_listbox_item when I try and add a new item all the previous items are updated to new item added. the code use is bellow

        private void add_menu_item_Click(object sender, RoutedEventArgs e)
    {
        new_menu_item form1 = new new_menu_item();
        form1.ShowDialog();

        new_listbox_item M_item = new new_listbox_item();
        M_item.new_item_name = form1.new_food.Text;
        M_item.price = double.Parse(form1.food_price.Text);
        M_item.vegitarian = form1.is_vegetarian.IsChecked == true;
        menu_Listbox.Items.Add(M_item);
    }

does anyone have any ideas on how to solve this issue? the new_listbox_item looks like this:

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

namespace MainServerWIndow
{    
   public class new_listbox_item
   {

       private static string _item_name;
       private static Boolean _vegitarian;
       private static double _price;
       private static double _total;
       private double N_price;


       public string new_item_name
       {
           get
           {
               return _item_name;
           }
           set
           {
               _item_name = value;
           }
       }

        public Boolean vegitarian
       {
           get
           {
               return _vegitarian;
           }
           set
           {
               _vegitarian = value;
           }
       }

        public  double price
        {
            get
            {
                return _price;
            }
            set
            {
                _price = value;
            }
        }

        public static string item_name
        {
            get
            {
                return _item_name;
            }
            set
            {
                _item_name = value;
            }
        }

        public static double item_price
        {
            get
            {
                return _price;
            }
            set
            {
                _price = value;
            }
        }

        public static Boolean vegetarian
        {
            get
            {
                return _vegitarian;
            }
            set
            {
                _vegitarian = value;
            }
        }


        public static double total
        {
            get
            {
                return _total;
            }
            set
            {
                _total = value;
            }
        }

        public override string ToString()
        {
            return string.Format("{0} {1} {2}", new_item_name, vegitarian, price);
        }
   }
} 

Answer 1

all the previous items are updated to new item added

Without a good, minimal , complete code example that reliably reproduces the problem it is impossible to know for sure what the problem is. But given the code you posted, there is certainly one serious code defect that would explain your problem. You have declared all but one of the fields in your class as static :

public class new_listbox_item
{
   private static string _item_name;
   private static Boolean _vegitarian;
   private static double _price;
   private static double _total;
   ...
}

By doing so, you have caused every instance of the new_listbox_item class to share the fields. Setting the field in one instance causes every other instance to use the new value; each instance does not have its own local copy of the field.

Remove the static keyword from all of those fields, and that will probably get your code working the way you want.