Creating a Custom Add or Edit Dialog in LightSwitch C# Beta2

^{Thanks to Sheel Shah for his informative posting Creating a Custom Add or Edit Dialog (Sheel Shah). Here is a work up of his solution in C# for Beta2, with allowing for the user clicking the X to close the child modal window:}

using System;
using System.Linq;
using System.IO;
using System.IO.IsolatedStorage;
using System.Collections.Generic;
using Microsoft.LightSwitch;
using Microsoft.LightSwitch.Framework.Client;
using System.Windows.Controls;
using Microsoft.LightSwitch.Presentation;
using Microsoft.LightSwitch.Presentation.Extensions;

namespace LightSwitchApplication
{
    public partial class Application
    {
    }
    public class DialogHelper
    {
        Microsoft.LightSwitch.Client.IScreenObject _screen;
        Microsoft.LightSwitch.Client.IVisualCollection _collection;
        String _dialogName;

        bool _isEditing;
        bool _isOK;  //added to allow for user clicking on X
        bool _doOnce; //added to allow only one closing handler

        IEntityObject _entity;

        public DialogHelper(Microsoft.LightSwitch.Client.IVisualCollection visualCollection,
                     String dialogName)
        {
            _screen = visualCollection.Screen;
            _collection = visualCollection;
            _dialogName = dialogName;
            _isOK = false; //added to allow for user clicking on X
            _doOnce = true; //added to allow only one closing handler
        }

        public void InitializeUI()
        {
            // following moved to BaseOpenDialog as workaround for beta2
            //bug: Modal window does not fire control available on open.
            //_screen.FindControl(_dialogName).ControlAvailable +=
            //     new EventHandler<ControlAvailableEventArgs>(DialogHelper_ControlAvailable);
            //_screen.FindControl(_dialogName).ControlUnavailable +=
            //    new EventHandler<ControlUnavailableEventArgs>(DialogHelper_ControlUnavailable);
        }

        void DialogHelper_ControlAvailable(object sender, ControlAvailableEventArgs e)
        {
            if (_doOnce)
            {
                ChildWindow childwindow = e.Control as ChildWindow;
                childwindow.Closed += new EventHandler(childwindow_Closed);
                _doOnce = false;
            }
            _screen.FindControl(_dialogName).ControlUnavailable -= new
                    EventHandler<ControlUnavailableEventArgs>(DialogHelper_ControlUnavailable);
        }

        void childwindow_Closed(object sender, EventArgs e)
        {
            if (_entity != null)
            {
                if (_isOK)
                {
                    (_entity.Details as System.ComponentModel.IEditableObject).EndEdit();
                }
                else
                {
                    if (_isEditing)
                    {
                        //cancel edit on close without ok (cancel or click X)
                        (_entity.Details as System.ComponentModel.IEditableObject).CancelEdit();
                    }
                    else
                    {
                        //on add if not ok discard, do not add blank row
                        _entity.Details.DiscardChanges();
                    }
                }
                _isOK = false;
            }
        }

        public bool CanEditSelected()
        {
            return _collection.CanEdit && (_collection.SelectedItem != null);
        }

        public bool CanAdd()
        {
            return _collection.CanAddNew;
        }

        public void AddEntity()
        {
            _isEditing = false;
            _collection.AddNew();
            _screen.FindControl(_dialogName).DisplayName = "Add " +
                _collection.Details.GetModel().ElementType.Name;
            BaseOpenDialog();
        }

        public void EditSelectedEntity()
        {
            _isEditing = true;
            _screen.FindControl(_dialogName).DisplayName = "Edit " +
                _collection.Details.GetModel().ElementType.Name;
            BaseOpenDialog();
        }

        private void BaseOpenDialog()
        {
            _entity = _collection.SelectedItem as IEntityObject;
            if (_entity != null)
            {
                Microsoft.LightSwitch.Threading.Dispatchers.Main.BeginInvoke(() =>
                {
                    (_entity.Details as System.ComponentModel.IEditableObject).EndEdit();
                    (_entity.Details as System.ComponentModel.IEditableObject).BeginEdit();
                }
                    );
                _screen.OpenModalWindow(_dialogName);
                //after beta 2 following can be moved to IntializeUI
                _screen.FindControl(_dialogName).ControlAvailable += new
                        EventHandler<ControlAvailableEventArgs>(DialogHelper_ControlAvailable);
                _screen.FindControl(_dialogName).ControlUnavailable += new
                        EventHandler<ControlUnavailableEventArgs>(DialogHelper_ControlUnavailable);
            }
        }

        void DialogHelper_ControlUnavailable(object sender, ControlUnavailableEventArgs e)
        {
            _screen.FindControl(_dialogName).ControlAvailable -= new
                    EventHandler<ControlAvailableEventArgs>(DialogHelper_ControlAvailable);
        }

        public void DialogOK()
        {
            _isOK = true;
            _screen.CloseModalWindow(_dialogName);
        }

        public void DialogCancel()
        {
            _screen.CloseModalWindow(_dialogName);
        }
    }
}

   

^{With calling code:}

^{using System;
using System.Linq;
using System.IO;
using System.IO.IsolatedStorage;
using System.Collections.Generic;
using Microsoft.LightSwitch;
using Microsoft.LightSwitch.Framework.Client;
using Microsoft.LightSwitch.Presentation;
using Microsoft.LightSwitch.Presentation.Extensions;
namespace LightSwitchApplication
{
    public partial class EditableCustomersGrid
    {
        private DialogHelper customersDialogHelper;}

        ^{partial void EditableCustomersGrid_InitializeDataWorkspace(
            System.Collections.Generic.List<IDataService> saveChangesTo)
        {
            customersDialogHelper = new DialogHelper(this.Customers, "CustomerEditDialog");
        }}

        ^{partial void EditableCustomersGrid_Created()
        {
            //customersDialogHelper.InitializeUI(); //not for beta2
        }}

        ^{partial void gridAddAndEditNew_CanExecute(ref bool result)
        {
            result = customersDialogHelper.CanAdd();
        }}

        ^{partial void gridAddAndEditNew_Execute()
        {
            customersDialogHelper.AddEntity();
        }}

        ^{partial void gridEditSelected_CanExecute(ref bool result)
        {
            result = customersDialogHelper.CanEditSelected();
        }}

        ^{partial void gridEditSelected_Execute()
        {
            customersDialogHelper.EditSelectedEntity();
        }}

        ^{partial void EditDialogOK_Execute()
        {
            customersDialogHelper.DialogOK();
        }}

        ^{partial void EditDialogCancel_Execute()
        {
            customersDialogHelper.DialogCancel();
        }
    }
}}

^{Note: a reference to System.Windows.Controls has been added to the Client project.}