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Data Binding in Windows Form
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sbelini View Drop Down
IdeaBlade
IdeaBlade
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Joined: 13-Aug-2010
Location: Oakland
Posts: 786 		Post Options Post Options   Quote sbelini Quote  Post ReplyReply Direct Link To This Post Topic: Data Binding in Windows Form
    Posted: 11-Jul-2012 at 11:11am
Hi,
 
Have you taken a look at our WinForms sample? You can download it in the DevForce Resource Center.
 
Regards,
   Silvio.
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duyhungb5 View Drop Down
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Joined: 11-Jul-2012
Posts: 1 		Post Options Post Options   Quote duyhungb5 Quote  Post ReplyReply Direct Link To This Post Posted: 11-Jul-2012 at 2:59am
I have using DevForce create small Application in WinForm
But I have Problem I can't binding data in Form Load Event Athough When Form display If I click Button call to Method Binding then Data is binding to Data Grid View.
 EmployeeModel viewModel;
        public Form1()
        {
            InitializeComponent();
            viewModel = new EmployeeModel();
           
        }

//Event Is Ok
        private void button1_Click(object sender, EventArgs e)
        {
            this.employeeBindingSource.DataSource = viewModel.Employees;
            this.dataGridView1.DataSource = null;
            this.dataGridView1.DataSource = this.employeeBindingSource;
           
        }

//Event Is not Display Data in Data GridView
        private void Form1_Load(object sender, EventArgs e)
        {
            
            this.dataGridView1.DataSource = viewModel.Employees;
            dataGridView1.Refresh();            
            
        }

I have create class using DevForce
public class EmployeeModel : INotifyPropertyChanged
    {
        #region "Define Variable"
        private NorthwindEntities _mgr = new NorthwindEntities();

        public ObservableCollection<Employee> Employees { get; private set; }
        public ObservableCollection<string> Log { get; private set; }
        #endregion

        #region "Property Event"
        public event PropertyChangedEventHandler PropertyChanged = delegate { };
        #endregion

        #region "Define Property"
        private string _busyPropertyName;
        private bool _isBusy;
        public bool IsBusy
        {
            get { return _isBusy; }
            set
            {
                _isBusy = value; RaisePropertyChanged(_busyPropertyName);
            }
        }

        public bool IsOrderBusy { get { return _isBusy; } }

        private Employee _currentEmployee;
        public Employee CurrentEmployee
        {
            get { return _currentEmployee; }
            set { _currentEmployee = value; RaisePropertyChanged("CurrentEmployee"); }
        }


        private int _currentPosition = -1;
        public int CurrentPosition
        {
            get { return _currentPosition; }
            set
            {
                if (Employees != null && Employees.Count > 0)
                {
                    _currentPosition = Math.Min(Math.Max(value, 0), Employees.Count - 1);
                    CurrentEmployee = Employees[_currentPosition];
                }
                else
                {
                    _currentPosition = -1;
                    CurrentEmployee = null;
                }
                RaisePropertyChanged("CurrentPosition");
            }
        }

        private bool _hasChanges = false;

        public bool HasChanges
        {
            get { return _hasChanges; }
            private set
            {
                _hasChanges = value;
                RaisePropertyChanged("HasChanges");
            }
        }


        private EntityQuery<Employee> _query;

        #endregion

        #region "Construction"
        public EmployeeModel()
        {
            Employees = new ObservableCollection<Employee>();
            Employees.CollectionChanged += Employees_CollectionChanged;
            Log = new ObservableCollection<string>();
            _busyPropertyName = "IsBusy"; 
            _mgr.Fetching += (s, e) =>
            {
                IsBusy = true;
                WriteToLog(e.Query);
            };
            _mgr.Queried += (s, e) =>
            {
                IsBusy = false;
                _busyPropertyName = "IsOrderBusy";
                WriteToLog("Query returned " + e.Results.Cast<object>().Count());
            };
            //_mgr.EntityChanged += (s, args) => HasChanges = ((NorthwindEntities)s).HasChanges();

            _query = _mgr.Employees;
            var op = _query.ExecuteAsync();
            op.Completed += GotEmployees;
            //_query.ExecuteAsync(
            //                op =>
            //                {
            //                    if (op.HasError)
            //                    {
            //                        throw new InvalidOperationException("Query failed: " + op.Error);
            //                    }
            //                    op.Results.ForEach(Employees.Add);
            //                    CurrentEmployee = Employees.FirstOrDefault();

            //                });  
            
        }
        #endregion


        #region "Write Log"
        private void WriteToLog(IEntityQuery query)
        {
            var returnType = query.ElementType;
            var message = (returnType == typeof(Order))
                ? "Fetching Orders from Employee " + CurrentEmployee.EmployeeID
                : "Fetching " + returnType;
            WriteToLog(message);
        }

        private void WriteToLog(string message)
        {
            Log.Insert(0, message);
        }
        #endregion


        #region "Entity Method"
        private void GotEmployees(object sender, EntityQueriedEventArgs<Employee> args)
        {
            if (args.HasError)
            {
                 throw new InvalidOperationException("Query failed: " + args.Error);
            }
            args.Results.ForEach(Employees.Add);
            CurrentEmployee = Employees.FirstOrDefault();
        }

        public void Save()
        {
            _mgr.SaveChangesAsync();
        }

        private void Add(System.Collections.Generic.IEnumerable<Employee> employees)
        {
            //_mgr.AddEntities(employees);
            //Save();
            //employees.ForEach(_mgr.AddEntity);
            if (employees.Any(emp => emp.EntityAspect.EntityState.IsDetached()))
            {
                _mgr.AddEntities(employees);
            }
                        
        }

        private void Delete(IEnumerable<Employee> employees)
        {
            employees.ForEach(emp => emp.EntityAspect.Delete());
            Save();
        }

        private void Employees_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
        {
            switch (e.Action)
            {
                case NotifyCollectionChangedAction.Add:
                    Add(e.NewItems.Cast<Employee>());
                    break;
                case NotifyCollectionChangedAction.Remove:
                    Delete(e.OldItems.Cast<Employee>());
                    break;
            }
        }

        public void RollbackChanges()
        {
            int privateCurrentPosition = CurrentPosition;
            _mgr.RejectChanges();
            Employees.Clear();
            _query.With(QueryStrategy.CacheOnly).Execute().ForEach(Employees.Add);
            CurrentPosition = privateCurrentPosition;
        }

        #endregion

        #region "Private Method"
        private void RaisePropertyChanged(string property)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(property));
        }
        void _mgr_Fetching(object sender, EntityFetchingEventArgs e)
        {
            WriteToLog("Fetching " + e.Query.ElementType);
        }
        #endregion

    }
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