Почти вся логика обновления данных в БД изменена таким образом, чтобы сначала юзер изменял данные в окне, и только после завершения работы с окном, данные обновлялись в БД. И немножко рефакторинга Сompanies -> Company

eCompanies/App.xaml.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Data;
 using System.Linq;
@@ -11,51 +12,78 @@ namespace eCompanies
     /// </summary>
     public partial class App : Application
     {
+        public static ObservableCollection<Company> getCompanies()
+        {
+            using (var db = new CompaniesDBContext())
+                return new ObservableCollection<Company>(db.Company.AsEnumerable()); 
+        }
+
+        public static HashSet<Users> getUsers(int id)
+        {
+            using (var db = new CompaniesDBContext())
+                return new HashSet<Users>(db.Users.Where(b => b.CompanyId.Equals(id)));
+        }
+        
         private void addCompany(Company c)
         {
             using (var db = new CompaniesDBContext())
             {
                 db.Company.Add(c);
-                var count = db.SaveChanges();
+                db.SaveChanges();
             }
         }
 
-        public static ObservableCollection<Company> getCompanies()
+        public static void updateCompany(Company c)
         {
             using (var db = new CompaniesDBContext())
-                return new ObservableCollection<Company>(db.Company.AsEnumerable()); 
+            {
+                db.Company.Update(c);
+                db.SaveChanges();
+            }
         }
 
-        public static HashSet<Users> getUsers(int id)
+        public static void removeCompany(int id)
         {
             using (var db = new CompaniesDBContext())
-                return new HashSet<Users>(db.Users.Where(b => b.CompanyId.Equals(id)));
+            {
+                var x = db.Company.Where(i => i.CompanyId.Equals(id));
+                foreach (Company c in x) db.Company.Remove(c);
+                db.SaveChanges();
+            }
         }
         
-        public static void updateCompany(Company c)
+        public static void removeCompany(List<int> idList)
         {
             using (var db = new CompaniesDBContext())
             {
-                db.Company.Update(c);
+                foreach (int id in idList)
+                {
+                    var x = db.Company.Where(i => i.CompanyId.Equals(id));
+                    foreach (Company c in x) db.Company.Remove(c);
+                }
                 db.SaveChanges();
             }
         }
 
-        public static void removeCompany(Company c)
+        public static void removeUser(int id)
         {
             using (var db = new CompaniesDBContext())
             {
-                db.Company.Remove(c);
+                var x = db.Users.Where(i => i.UserId.Equals(id));
+                foreach (Users u in x) db.Users.Remove(u);
                 db.SaveChanges();
             }
         }
 
-        public static void removeUser(int id)
+        public static void removeUser(List<int> idList)
         {
             using (var db = new CompaniesDBContext())
             {
-                var x = db.Users.Where(s => s.UserId.Equals(id));
+                foreach (int id in idList)
+                {
+                    var x = db.Users.Where(i => i.UserId.Equals(id));
                     foreach (Users u in x) db.Users.Remove(u);
+                }
                 db.SaveChanges();
             }
         }

eCompanies/Companies.cs → eCompanies/Company.cs

@@ -11,7 +11,6 @@ namespace eCompanies
             contract = new Contract(this);
         }
         
-
         public Contract contract { get; set; }
         public int CompanyId { get; set; }
         public string Name { get; set; }

eCompanies/MainWindow.xaml

@@ -5,9 +5,10 @@
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
         xmlns:local="clr-namespace:eCompanies"
         mc:Ignorable="d"
-        Title="MainWindow" Height="450" Width="800">
+        Title="MainWindow" Height="450" Width="800" Closing="Window_Closing">
     <Grid>
-        <DataGrid x:Name="companyGrid" HorizontalAlignment="Left" Height="399" Margin="10,10,0,0" VerticalAlignment="Top" Width="772" ItemsSource="{Binding}" AutoGenerateColumns="False">
+        <DataGrid x:Name="companyGrid" HorizontalAlignment="Left" Height="399" Margin="10,10,0,0" VerticalAlignment="Top" 
+                  Width="772" ItemsSource="{Binding}" AutoGenerateColumns="False">
             <DataGrid.Resources>
                 <ContextMenu x:Key="RowMenu" 
                     DataContext="{Binding PlacementTarget.DataContext, RelativeSource={RelativeSource Self}}">

eCompanies/MainWindow.xaml.cs

@@ -19,42 +19,97 @@ namespace eCompanies
     /// <summary>
     /// Логика взаимодействия для MainWindow.xaml
     /// </summary>
-    public delegate void UpdateCompanyGridDelegate();
+    public delegate void UpdateCompanyGridDelegate(Company updatingCompany);
     public partial class MainWindow : Window
     {
+        List<int> deletingCompanyList = new List<int>();
+        List<int> updatingCompanyList = new List<int>();
         UsersWindow usersWindowInstance = null;
+
         public MainWindow()
         {
             InitializeComponent();
-            updateCompanyGrid();
+            companyGrid.DataContext = App.getCompanies();
         }
         
-        private void updateCompanyGrid()
+        private void updateCompanyItem(Company updatingCompany)
         {
-            companyGrid.DataContext = App.getCompanies();
+            if (updatingCompany == null) return;
+            updatingCompanyList.Add(updatingCompany.CompanyId);
+            var context = ((ObservableCollection<Company>)companyGrid.DataContext).ToList<Company>();
+            for (int i = 0; i < context.Count; i++)
+            { 
+                if (context[i].CompanyId.Equals(updatingCompany.CompanyId))
+                {
+                    context[i] = updatingCompany;
+                    companyGrid.DataContext = new ObservableCollection<Company>(context);
+                    updatingCompanyList.Add(updatingCompany.CompanyId);
+                    return;
+                }
             }
+        }
+        
 
         private void RowEdit_Click(object sender, RoutedEventArgs e)
         {
-            try
-            {
-                UpdateCompanyGridDelegate d = updateCompanyGrid;
+            UpdateCompanyGridDelegate d = updateCompanyItem;
             Company company = (Company)companyGrid.CurrentItem;
             if (usersWindowInstance != null) usersWindowInstance.Close();
             usersWindowInstance = new UsersWindow(company, d);
             usersWindowInstance.Show();
         }
-            catch { }
-        }
 
         private void RowDelete_Click(object sender, RoutedEventArgs e)
         {
-            try
+            deleteCompanyFromGrid();
+        }
+
+        private void deleteCompanyFromGrid()
         {
-                Company company = (Company)companyGrid.CurrentItem;
-                App.removeCompany(company);
+            var companies = (ObservableCollection<Company>)companyGrid.DataContext;
+            foreach (Company c in companies)
+            {
+                int deletingUser = ((Company)companyGrid.CurrentItem).CompanyId;
+                if (Equals(c.CompanyId, deletingUser))
+                {
+                    deletingCompanyList.Add(((Company)companyGrid.CurrentItem).CompanyId);
+                    companies.Remove(c);
+                    companyGrid.DataContext = companies;
+                    return;
                 }
-            catch { }
+            }
+        }
+
+        private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
+        {
+
+            MessageBoxResult mbr = MessageBox.Show("Вы закрываете приложение. Хотите сохранить результаты?", "Сохранение изменений", MessageBoxButton.YesNo);
+            if (mbr == MessageBoxResult.No)
+                return;
+            foreach (Company c in (ObservableCollection<Company>)companyGrid.DataContext)
+            {
+                if (c.Name == null)
+                {
+                    mbr = MessageBox.Show("Вы не заполнили поле [Название компании]! " +
+                        "Вернуться к форме для исправления? (При ответе Нет все данные будут потеряны!)",
+                        "Поле [Название компании] не может быть пустым!",
+                        MessageBoxButton.YesNo);
+
+                    if (mbr == MessageBoxResult.Yes)
+                    {
+                        e.Cancel = true;
+                        return;
+                    }
+                    else if (mbr == MessageBoxResult.No)
+                        return;
+                }
+
+                if (deletingCompanyList != null)
+                    App.removeCompany(deletingCompanyList);
+                deletingCompanyList = null;
+                // TODO: реализация обновления старых компаний и добавления новых
+            }
+
         }
     }
 }

eCompanies/UsersWindow.xaml

@@ -11,7 +11,8 @@
             <ColumnDefinition/>
             <ColumnDefinition Width="0*"/>
         </Grid.ColumnDefinitions>
-        <DataGrid x:Name="usersGrid" HorizontalAlignment="Left" Height="354" Margin="10,55,0,0" VerticalAlignment="Top" Width="772" ItemsSource="{Binding}" AutoGenerateColumns="False" RowEditEnding="usersGrid_RowEditEnding" AddingNewItem="usersGrid_AddingNewItem">
+        <DataGrid x:Name="usersGrid" HorizontalAlignment="Left" Height="354" Margin="10,55,0,0" VerticalAlignment="Top" 
+                  Width="772" ItemsSource="{Binding}" AutoGenerateColumns="False">
             <DataGrid.Columns>
                 <DataGridTextColumn Header="ID" IsReadOnly="True" Binding="{Binding UserId}"/>
                 <DataGridTextColumn Header="Имя пользователя" Width="*" Binding="{Binding Name}" />

eCompanies/UsersWindow.xaml.cs

@@ -1,8 +1,8 @@
 using System;
+using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Linq;
 using System.Windows;
-using System.Windows.Controls;
 using System.Windows.Input;
 
 namespace eCompanies
@@ -13,53 +13,80 @@ namespace eCompanies
     public partial class UsersWindow : Window
     {
         Company currentCompany;
-        UpdateCompanyGridDelegate updateCompanyGrid;
+        UpdateCompanyGridDelegate updateCompanyItem;
+        List<int> deletingUsersList = new List<int>();
+
         public UsersWindow(Company c, UpdateCompanyGridDelegate d)
         {
             InitializeComponent();
             currentCompany = c;
-            updateCompanyGrid = d;
-            updateUsersGrid();
+            updateCompanyItem = d;
+            updateUsersGrid(c); 
         }
 
-        private void updateUsersGrid()
+        private void updateUsersGrid(Company c)
         {
-            currentCompany.Users = App.getUsers(currentCompany.CompanyId);
-            companyNameBox.Text = currentCompany.Name;
-            contractStatusComboBox.SelectedIndex = currentCompany.ContractStatus;
-            usersGrid.DataContext = new ObservableCollection<Users>(currentCompany.Users.AsEnumerable());
+            companyNameBox.Text = c.Name;
+            contractStatusComboBox.SelectedIndex = c.ContractStatus;
+            currentCompany.Users = App.getUsers(c.CompanyId);
+            usersGrid.DataContext = new ObservableCollection<Users>(c.Users.AsEnumerable());
         }
 
-
         private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
         {
             MessageBoxResult mbr = MessageBox.Show("Вы закрываете окно с компанией. Хотите сохранить результаты?", "Сохранение изменений", MessageBoxButton.YesNo);
             if (mbr == MessageBoxResult.No)
                 return;
+            currentCompany.Users.Clear();
             foreach (Users u in (ObservableCollection<Users>)usersGrid.DataContext)
             {
+                if (u.Login == null || u.Password == null || u.Name == null)
+                {
+                    mbr = MessageBox.Show("Вы не полностью заполнили поле одного из пользователей! " +
+                        "Вернуться к форме для исправления? (При ответе Нет все данные будут потеряны!)", 
+                        "Поле Логин/Пароль не может быть пустым!", 
+                        MessageBoxButton.YesNo);
+
+                    if (mbr == MessageBoxResult.Yes)
+                    {
+                        e.Cancel = true;
+                        return;
+                    } else if (mbr == MessageBoxResult.No)
+                        return;
+                }
+
+                if (deletingUsersList != null)
+                    App.removeUser(deletingUsersList);
+
                 u.CompanyId = currentCompany.CompanyId;
                 u.Company = currentCompany;
                 currentCompany.Users.Add(u);
             }
+
             currentCompany.ContractStatus = contractStatusComboBox.SelectedIndex;
             currentCompany.Name = companyNameBox.Text;
-            App.updateCompany(currentCompany);
-            updateCompanyGrid();
+            updateCompanyItem(currentCompany);
         }
 
-        private void usersGrid_RowEditEnding(object sender, DataGridRowEditEndingEventArgs e)
+        private void deleteUserFromGrid()
         {
-        }
-
-        private void usersGrid_AddingNewItem(object sender, AddingNewItemEventArgs e)
+            var users = (ObservableCollection<Users>)usersGrid.DataContext;
+            foreach (Users u in users)
             {
+                int deletingUser = ((Users)usersGrid.CurrentItem).UserId;
+                if (Equals(u.UserId, deletingUser))
+                {
+                    deletingUsersList.Add(((Users)usersGrid.CurrentItem).UserId);
+                    users.Remove(u);
+                    usersGrid.DataContext = users;
+                    return;
+                }
+            }
         }
 
         private void RowDelete_Click(object sender, RoutedEventArgs e)
         {
-            App.removeUser(((Users)usersGrid.CurrentItem).UserId);
-            updateUsersGrid();
+            deleteUserFromGrid();
         }
     }
 }

eCompanies/eCompanies.csproj

@@ -154,7 +154,7 @@
       <DependentUpon>App.xaml</DependentUpon>
       <SubType>Code</SubType>
     </Compile>
-    <Compile Include="Companies.cs" />
+    <Compile Include="Company.cs" />
     <Compile Include="MainWindow.xaml.cs">
       <DependentUpon>MainWindow.xaml</DependentUpon>
       <SubType>Code</SubType>