I have a book table in my database and I have book view named vwShared in my edmx. I want to create dynamic search with operators for user to find books. I have 2 SearchColumns dropdownlist contains "Title, Authors, Published Year, Subject". I have 2 SearchType dropdownlist contains "StartsWith, Contains, EndsWith, Equals". I have another dropdownlist contains "AND, OR" to combine 2 search results. The following is my code.
var predicate = PredicateBuilder.True<DataLayer.vwShared>();
if (joinOperator == "AND")
{
if (SearchColumn1 == "Title" && SearchType1 == "Contains")
predicate = predicate.And(e1 => e1.Title.Contains(txtSearch1.Text));
if (SearchColumn2 == "Authors" && SearchType2 == "Contains")
predicate = predicate.And(e1 => e1.Authors.Contains(txtSearch2.Text));
}
else if (joinOperator == "OR")
{
if (SearchColumn1 == "Title" && SearchType1 == "Contains")
predicate = predicate.Or(e1 => e1.Title.Contains(txtSearch1.Text));
if (SearchColumn2 == "Authors" && SearchType2 == "Contains")
predicate = predicate.Or(e1 => e1.Authors.Contains(txtSearch2.Text));
}
List<DataLayer.vwShared> bookList= new DataLayer.Solib_DMREntities().SP_SharedData_GetAll("AllLocal").ToList<DataLayer.vwShared>();
var bookList= from books in bookList.AsQueryable().Where(predicate)
select books ;
gvBooks.DataSource = bookList.ToList();
gvBooks.DataBind();
The above code not return proper results. Is there something wrong. ?
The following is my references website.
http://www.albahari.com/nutshell/predicatebuilder.aspx
Please give me advice.
Thanks.
Answering your concrete question. The problem is in the branch for building OR predicate, in which case you should start with PredicateBuilder.False, otherwice there will not be filtering at all (as we know from the school, true or something is always true :)
// ...
else if (joinOperator == "OR")
{
predicate = PredicateBuilder.False<DataLayer.vwShared>();
// ...
}
// ...
step 1:Model
public class Person
{
public int PersonId { get; set; }
public int? Age { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public int? Salary { get; set; }
}
public class PersonDBContext : DbContext
{
public virtual DbSet<Person> People { get; set; }
}
step 2 : controller
public class PersonController
{
PersonDBContext db = new PersonDBContext();
public void Add(Person person)
{
db.People.Add(person);
db.SaveChanges();
}
public List<Person> GetAll()
{
return db.People.ToList();
}
public List<Person> GetByPredicateValue(Expression<Func<Person, bool>> predicate)
{
if (predicate != null)
return db.People.Where(predicate.Compile()).ToList();
else
return null;
}
public List<Person> GetByPredicateAndPersonListValue(List<Person> PeopleList,Expression<Func<Person, bool>> predicate)
{
if (predicate != null)
return PeopleList.Where(predicate.Compile()).ToList();
else
return null;
}
}
step 3: code behind
public partial class MainWindow : Window
{
PersonController pc;
public static List<Person> PeopleFilterList = null;
public static string CurrentColumn = null;
public MainWindow()
{
pc = new PersonController();
InitializeComponent();
grid.ItemsSource = pc.GetAll();
grid.PreviewMouseDown += grid_PreviewMouseDown;
}
void grid_PreviewMouseDown(object sender, MouseButtonEventArgs e)
{
TableViewHitInfo hi = ((TableView)grid.View).CalcHitInfo(e.OriginalSource as DependencyObject);
if (hi == null) return;
if (hi.HitTest == TableViewHitTest.ColumnHeader || hi.HitTest == TableViewHitTest.ColumnHeaderFilterButton)
{
grid.UnselectAll();
GridColumn currentColumn = ((DevExpress.Xpf.Grid.GridViewHitInfoBase)(hi)).Column;
CurrentColumn = currentColumn.FieldName;
(grid.View as TableView).SelectCells(0, currentColumn, grid.VisibleRowCount - 1, currentColumn);
}
}
Expression<Func<Person, bool>> _result=null;
string str="";
private void IdForm_ButtonClicked(object sender, IdentityUpdateEventArgs e)
{
_result = e.FirstName;
}
public MainWindow(Expression<Func<Person, bool>> result)
{
Window1 f = new Window1();
f.IdentityUpdated += new Window1.IdentityUpdateHandler(IdForm_ButtonClicked);
pc = new PersonController();
InitializeComponent();
_result = result;
if (PeopleFilterList != null)
PeopleFilterList = pc.GetByPredicateAndPersonListValue(PeopleFilterList,_result).ToList();
else
PeopleFilterList = pc.GetByPredicateValue(_result).ToList();
grid.ItemsSource = PeopleFilterList;
grid.PreviewMouseDown += grid_PreviewMouseDown;
}
private void Button_Click(object sender, RoutedEventArgs e)
{
Window1 w1 = new Window1(CurrentColumn);
w1.Show();
}
}
step 4 : Filter code behind
public partial class Window1 : Window
{
public delegate void IdentityUpdateHandler(object sender, IdentityUpdateEventArgs e);
public event IdentityUpdateHandler IdentityUpdated;
string _currentColumn = null;
public Window1()
{
InitializeComponent();
}
public Window1(string currentColumn)
{
_currentColumn = currentColumn;
InitializeComponent();
}
public static Expression<Func<Person, bool>> predicateValue;
IdentityUpdateEventArgs args;
private void Button_Click(object sender, RoutedEventArgs e)
{
string operatorName = "";
if (!String.IsNullOrEmpty(txtSmaller.Text.Trim()))
operatorName = txtSmaller.Name;
else if (!String.IsNullOrEmpty(txtElder.Text.Trim()))
operatorName = txtElder.Name;
else if (!String.IsNullOrEmpty(txtContains.Text.Trim()))
operatorName = txtContains.Name;
else if (!String.IsNullOrEmpty(txtStartWith.Text.Trim()))
operatorName = txtStartWith.Name;
else if (!String.IsNullOrEmpty(txtEqual.Text.Trim()))
operatorName = txtEqual.Name;
else if (!String.IsNullOrEmpty(txtNotEqual.Text.Trim()))
operatorName = txtNotEqual.Name;
else if (!String.IsNullOrEmpty(txtSmallerOrEqual.Text.Trim()))
operatorName = txtSmallerOrEqual.Name;
else if (!String.IsNullOrEmpty(txtElderOrEqual.Text.Trim()))
operatorName = txtElderOrEqual.Name;
else if (!String.IsNullOrEmpty(txtSmallerThan.Text.Trim()) && !String.IsNullOrEmpty(txtBiggerThan.Text.Trim()))
operatorName = txtSmallerThan.Name;
switch (operatorName)
{
case "txtSmaller":
predicateValue = (x => (int)x.GetType().GetProperty(_currentColumn).GetValue(x, null) < Convert.ToInt32(txtSmaller.Text));
break;
case "txtElder":
predicateValue = (x => (int)x.GetType().GetProperty(_currentColumn).GetValue(x, null) > Convert.ToInt32(txtElder.Text));
break;
case "txtSmallerOrEqual":
predicateValue = (x => (int)x.GetType().GetProperty(_currentColumn).GetValue(x, null) <= Convert.ToInt32(txtSmallerOrEqual.Text));
break;
case "txtElderOrEqual":
predicateValue = (x => (int)x.GetType().GetProperty(_currentColumn).GetValue(x, null) >= Convert.ToInt32(txtElderOrEqual.Text));
break;
case "txtEqual":
predicateValue = (x => (int)x.GetType().GetProperty(_currentColumn).GetValue(x, null) == Convert.ToInt32(txtEqual.Text));
break;
case "txtNotEqual":
predicateValue = (x => (int)x.GetType().GetProperty(_currentColumn).GetValue(x, null) != Convert.ToInt32(txtNotEqual.Text));
break;
case "txtSmallerThan":
predicateValue = (x => (int)x.GetType().GetProperty(_currentColumn).GetValue(x, null) >= Convert.ToInt32(txtBiggerThan.Text)
&& (int)x.GetType().GetProperty(_currentColumn).GetValue(x, null) <= Convert.ToInt32(txtSmallerThan.Text));
break;
case "txtStartWith":
predicateValue = (x => x.GetType().GetProperty(_currentColumn).GetValue(x, null).ToString().StartsWith(txtStartWith.Text));
break;
case "txtContains":
predicateValue = (x => x.GetType().GetProperty(_currentColumn).GetValue(x,null).ToString().Contains(txtContains.Text));
break;
}
MainWindow mw = new MainWindow(predicateValue);
mw.Show();
this.Close();
}
void Window1_IdentityUpdated(object sender, IdentityUpdateEventArgs e)
{
e = args;
}
}
public class IdentityUpdateEventArgs : System.EventArgs
{
private Expression<Func<Person, bool>> mFirstName;
public IdentityUpdateEventArgs(Expression<Func<Person, bool>> sFirstName)
{
this.mFirstName = sFirstName;
}
public Expression<Func<Person, bool>> FirstName
{
get
{
return mFirstName;
}
}
}
Related
I am trying to implement below java code in c# referring to Android documentation
List<String> skuList = new ArrayList<> ();
skuList.add("premium_upgrade");
skuList.add("gas");
SkuDetailsParams.Builder params = SkuDetailsParams.newBuilder();
params.setSkusList(skuList).setType(SkuType.INAPP);
billingClient.querySkuDetailsAsync(params.build(),
new SkuDetailsResponseListener() {
#Override
public void onSkuDetailsResponse(BillingResult billingResult,
List<SkuDetails> skuDetailsList) {
// Process the result.
}
});
I have here 2 questions. I thought that i would run this code on a separate thread than UI thread like below to keep my ui responsive while network connection is done. is that the correct approach? QuerySkuDetailsAsync is called async but doesnt implement as async. how should this be working and how to handle in c# because it will fire and forget but Listener to handle the response.
public async Task<List<InAppBillingProduct>> GetProductsAsync(List<string> ProductIds)
{
var getSkuDetailsTask = Task.Factory.StartNew(() =>
{
var prms = SkuDetailsParams.NewBuilder();
var type = BillingClient.SkuType.Inapp;
prms.SetSkusList(ProductIds).SetType(type);
BillingClient.QuerySkuDetailsAsync(prms.Build(), new SkuDetailsResponseListener());
return InAppBillingProducts;
});
return await getSkuDetailsTask;
}
2nd question regarding how to handle with the listener as below. How do I return value from the listener. I need return list of InAppBillingProduct object.
public class SkuDetailsResponseListener : Java.Lang.Object, ISkuDetailsResponseListener
{
public void OnSkuDetailsResponse(BillingResult billingResult, IList<SkuDetails> skus)
{
if (billingResult.ResponseCode == BillingResponseCode.Ok)
{
// get list of Products here and return
}
}
}
FYI. This is how I did it. This is not a complete code but this will give you and idea.
Listener - PCL
============
private async Task EventClicked()
{
var skuList = new List<string>();
skuList.Add("[nameofsubscriptionfoundinyourgoogleplay]");
if (await _billingClientLifecycle.Initialize(skuList, DisconnectedConnection))
{
var firstProduct = _billingClientLifecycle?.ProductsInStore?.FirstOrDefault();
if (firstProduct != null)
{
//purchase here
}
}
}
private void DisconnectedConnection()
{
//Todo.alfon. handle disconnection here...
}
Interface - PCL
===========
public interface IInAppBillingMigratedNew
{
List<InAppBillingPurchase> PurchasedProducts { get; set; }
List<InAppBillingProduct> ProductsInStore { get; set; }
Task<bool> Initialize(List<String> skuList, Action onDisconnected = null);
}
Dependency - Platform Droid
===============
[assembly: XF.Dependency(typeof(InAppBillingMigratedNew))]
public class InAppBillingMigratedNew : Java.Lang.Object, IBillingClientStateListener
, ISkuDetailsResponseListener, IInAppBillingMigratedNew
{
private Activity Context => CrossCurrentActivity.Current.Activity
?? throw new NullReferenceException("Current Context/Activity is null");
private BillingClient _billingClient;
private List<string> _skuList = new List<string>();
private TaskCompletionSource<bool> _tcsInitialized;
private Action _disconnectedAction;
private Dictionary<string, SkuDetails> _skusWithSkuDetails = new Dictionary<string, SkuDetails>();
public List<InAppBillingPurchase> PurchasedProducts { get; set; }
public List<InAppBillingProduct> ProductsInStore { get; set; }
public IntPtr Handle => throw new NotImplementedException();
public Task<bool> Initialize(List<string> skuList, Action disconnectedAction = null)
{
_disconnectedAction = disconnectedAction;
_tcsInitialized = new TaskCompletionSource<bool>();
var taskInit = _tcsInitialized.Task;
_skuList = skuList;
_billingClient = BillingClient.NewBuilder(Context)
.SetListener(this)
.EnablePendingPurchases()
.Build();
if (!_billingClient.IsReady)
{
_billingClient.StartConnection(this);
}
return taskInit;
}
#region IBillingClientStateListener
public void OnBillingServiceDisconnected()
{
Console.WriteLine($"Connection disconnected.");
_tcsInitialized?.TrySetResult(false);
_disconnectedAction?.Invoke();
}
public void OnBillingSetupFinished(BillingResult billingResult)
{
var responseCode = billingResult.ResponseCode;
var debugMessage = billingResult.DebugMessage;
if (responseCode == BillingResponseCode.Ok)
{
QuerySkuDetails();
QueryPurchases();
_tcsInitialized?.TrySetResult(true);
}
else
{
Console.WriteLine($"Failed connection {debugMessage}");
_tcsInitialized?.TrySetResult(false);
}
}
#endregion
#region ISkuDetailsResponseListener
public void OnSkuDetailsResponse(BillingResult billingResult, IList<SkuDetails> skuDetailsList)
{
if (billingResult == null)
{
Console.WriteLine("onSkuDetailsResponse: null BillingResult");
return;
}
var responseCode = billingResult.ResponseCode;
var debugMessage = billingResult.DebugMessage;
switch (responseCode)
{
case BillingResponseCode.Ok:
if (skuDetailsList == null)
{
_skusWithSkuDetails.Clear();
}
else
{
if (skuDetailsList.Count > 0)
{
ProductsInStore = new List<InAppBillingProduct>();
}
foreach (var skuDetails in skuDetailsList)
{
_skusWithSkuDetails.Add(skuDetails.Sku, skuDetails);
//ToDo.alfon. make use mapper here
ProductsInStore.Add(new InAppBillingProduct
{
Name = skuDetails.Title,
Description = skuDetails.Description,
ProductId = skuDetails.Sku,
CurrencyCode = skuDetails.PriceCurrencyCode,
LocalizedIntroductoryPrice = skuDetails.IntroductoryPrice,
LocalizedPrice = skuDetails.Price,
MicrosIntroductoryPrice = skuDetails.IntroductoryPriceAmountMicros,
MicrosPrice = skuDetails.PriceAmountMicros
});
}
}
break;
case BillingResponseCode.ServiceDisconnected:
case BillingResponseCode.ServiceUnavailable:
case BillingResponseCode.BillingUnavailable:
case BillingResponseCode.ItemUnavailable:
case BillingResponseCode.DeveloperError:
case BillingResponseCode.Error:
Console.WriteLine("onSkuDetailsResponse: " + responseCode + " " + debugMessage);
break;
case BillingResponseCode.UserCancelled:
Console.WriteLine("onSkuDetailsResponse: " + responseCode + " " + debugMessage);
break;
// These response codes are not expected.
case BillingResponseCode.FeatureNotSupported:
case BillingResponseCode.ItemAlreadyOwned:
case BillingResponseCode.ItemNotOwned:
default:
Console.WriteLine("onSkuDetailsResponse: " + responseCode + " " + debugMessage);
break;
}
}
#endregion
#region Helper Methods Private
private void ProcessPurchases(List<Purchase> purchasesList)
{
if (purchasesList == null)
{
Console.WriteLine("No purchases done.");
return;
}
if (IsUnchangedPurchaseList(purchasesList))
{
Console.WriteLine("Purchases has not changed.");
return;
}
_purchases.AddRange(purchasesList);
PurchasedProducts = _purchases.Select(sku => new InAppBillingPurchase
{
PurchaseToken = sku.PurchaseToken
})?.ToList();
if (purchasesList != null)
{
LogAcknowledgementStatus(purchasesList);
}
}
private bool IsUnchangedPurchaseList(List<Purchase> purchasesList)
{
// TODO: Optimize to avoid updates with identical data.
return false;
}
private void LogAcknowledgementStatus(List<Purchase> purchasesList)
{
int ack_yes = 0;
int ack_no = 0;
foreach (var purchase in purchasesList)
{
if (purchase.IsAcknowledged)
{
ack_yes++;
}
else
{
ack_no++;
}
}
//Log.d(TAG, "logAcknowledgementStatus: acknowledged=" + ack_yes +
// " unacknowledged=" + ack_no);
}
private void QuerySkuDetails()
{
var parameters = SkuDetailsParams
.NewBuilder()
.SetType(BillingClient.SkuType.Subs)
.SetSkusList(_skuList)
.Build();
_billingClient.QuerySkuDetailsAsync(parameters, this);
}
private void QueryPurchases()
{
if (!_billingClient.IsReady)
{
Console.WriteLine("queryPurchases: BillingClient is not ready");
}
var result = _billingClient.QueryPurchases(BillingClient.SkuType.Subs);
ProcessPurchases(result?.PurchasesList?.ToList());
}
#endregion
}
If an object is clicked, the next page should not be called immediately. But the click should remain on the object until you scroll through a wipe to the next page.
How can it hold the click command on an Item?
How can it swipe from the clicked Item to an other Page?
Update
Click one item > OnHold> swipe from the holded item to the left and right.
This is the actual behavior:
private int index = -1;
break;
}
return true;
}
}
To highlight the item when it is clicked, you can set background color to the item's view, to perform a swipe gesture for each item, I think you will need to implement IOnTouchListener for each item. Here I created an adapter to implement this feature:
public class LVAdapter : BaseAdapter<ListItemModel>, View.IOnTouchListener
{
private List<ListItemModel> items = new List<ListItemModel>();
private Activity context;
private int index = -1;
public enum SwipeAction
{
LR, // Left to Right
RL, // Right to Left
TB, // Top to bottom
BT, // Bottom to Top
None // when no action was detected
}
private int MIN_DISTANCE = 100;
private float downX, downY, upX, upY;
private SwipeAction maction = SwipeAction.None;
public LVAdapter(Activity context, List<ListItemModel> items) : base()
{
this.context = context;
this.items = items;
}
public override ListItemModel this[int position]
{
get { return items[position]; }
}
public override int Count
{
get { return items.Count; }
}
public override long GetItemId(int position)
{
return position;
}
private void SetSelectedItem(int position)
{
index = position;
NotifyDataSetChanged();
}
private class MyViewHolder : Java.Lang.Object
{
public TextView Name { get; set; }
public TextView Description { get; set; }
public int index { get; set; }
}
public override View GetView(int position, View convertView, ViewGroup parent)
{
MyViewHolder holder = null;
var view = convertView;
if (view != null)
holder = view.Tag as MyViewHolder;
if (holder == null)
{
holder = new MyViewHolder();
view = context.LayoutInflater.Inflate(Resource.Layout.ItemCell, null);
holder.Name = view.FindViewById<TextView>(Resource.Id.nametxt);
holder.Description = view.FindViewById<TextView>(Resource.Id.detailtxt);
holder.index = position;
view.Tag = holder;
}
holder.Name.Text = items[position].Name;
holder.Description.Text = items[position].Description;
if (index != -1 && position == index)
{
holder.Name.SetBackgroundColor(Android.Graphics.Color.Red);
holder.Description.SetBackgroundColor(Android.Graphics.Color.Pink);
}
else
{
holder.Name.SetBackgroundColor(Android.Graphics.Color.RoyalBlue);
holder.Description.SetBackgroundColor(Android.Graphics.Color.SeaGreen);
}
view.SetOnTouchListener(this);
return view;
}
public bool OnTouch(View v, MotionEvent e)
{
switch (e.Action)
{
case MotionEventActions.Down:
downX = e.GetX();
downY = e.GetY();
maction = SwipeAction.None;
break;
case MotionEventActions.Move:
upX = e.GetX();
upY = e.GetY();
var deltaX = downX - upX;
var deltaY = downY - upY;
if (Math.Abs(deltaX) > MIN_DISTANCE)
{
if (deltaX < 0)
{
maction = SwipeAction.LR;
}
else if (deltaX > 0)
{
maction = SwipeAction.RL;
}
return true;
}
else if (Math.Abs(deltaY) > MIN_DISTANCE)
{
if (deltaY < 0)
{
maction = SwipeAction.TB;
}
else if (deltaY > 0)
{
maction = SwipeAction.BT;
}
return false;
}
break;
case MotionEventActions.Up:
var holder = v.Tag as MyViewHolder;
if (maction == SwipeAction.None)
{
SetSelectedItem(holder.index);
}
else if (maction == SwipeAction.LR | maction == SwipeAction.RL)
{
if (holder.index == index)
context.StartActivity(typeof(Activity1));
}
break;
}
return true;
}
}
The ListItemModel is quite simple by my side:
public class ListItemModel
{
public string Name { get; set; }
public string Description { get; set; }
}
You can try to modify the model and holder as you need.
I have a type which has a default sort order as it implements IComparable<T> and IComparable. I'm not getting the results I expect from LINQ , basically it looks as if the IComparable<T> which the type implements is not being applied.
I thought I would get the result I want with an expression in the form:
var result = MyEnumerable<T>.OrderBy(r => r);
where T itself implements IComparable<T>. It's not happening.
I can see related questions where specific IComparable<T> classes are specified for the sort, but I can't find one which uses the default IComparable<T> implemented by T itself.
My syntax is clearly incorrect. What is the correct syntax please?
Thanks in advance.
OrderBy uses the default comparer Comparer<T>.Default which in turn will default to use the IComparable<T> implementation for T, or the non-generic IComparable if the former does not exist.
This code works:
public class Program
{
static void Main(string[] args)
{
var list = new List<Stuff>
{
new Stuff("one"),
new Stuff("two"),
new Stuff("three"),
new Stuff("four")
};
var sorted = list.OrderBy(x => x);
foreach (var stuff in sorted)
{
Console.Out.WriteLine(stuff.Name);
}
}
}
public class Stuff : IComparable<Stuff>
{
public string Name { get; set; }
public Stuff(string name)
{
Name = name;
}
public int CompareTo(Stuff other)
{
return String.CompareOrdinal(Name, other.Name);
}
}
public static class GenericSorter
{
public static IOrderedEnumerable<T> Sort<T>(IEnumerable<T> toSort, Dictionary<string, SortingOrder> sortOptions)
{
IOrderedEnumerable<T> orderedList = null;
foreach (KeyValuePair<string, SortingOrder> entry in sortOptions)
{
if (orderedList != null)
{
if (entry.Value == SortingOrder.Ascending)
{
orderedList = orderedList.ApplyOrder<T>(entry.Key, "ThenBy");
}
else
{
orderedList = orderedList.ApplyOrder<T>(entry.Key, "ThenByDescending");
}
}
else
{
if (entry.Value == SortingOrder.Ascending)
{
orderedList = toSort.ApplyOrder<T>(entry.Key, "OrderBy");
}
else
{
orderedList = toSort.ApplyOrder<T>(entry.Key, "OrderByDescending");
}
}
}
return orderedList;
}
private static IOrderedEnumerable<T> ApplyOrder<T>(this IEnumerable<T> source, string property, string methodName)
{
ParameterExpression param = Expression.Parameter(typeof(T), "x");
Expression expr = param;
foreach (string prop in property.Split('.'))
{
expr = Expression.PropertyOrField(expr, prop);
}
Type delegateType = typeof(Func<,>).MakeGenericType(typeof(T), expr.Type);
LambdaExpression lambda = Expression.Lambda(delegateType, expr, param);
MethodInfo mi = typeof(Enumerable).GetMethods().Single(
method => method.Name == methodName
&& method.IsGenericMethodDefinition
&& method.GetGenericArguments().Length == 2
&& method.GetParameters().Length == 2)
.MakeGenericMethod(typeof(T), expr.Type);
return (IOrderedEnumerable<T>)mi.Invoke(null, new object[] { source, lambda.Compile() });
}
}
Let's say I have the following tables in a database forming a Many-to-Many Relationship. And in an ASP.Net MVC project using EF 4.1, I have corresponding POCO entities and a Repository layer to access the database.
People: PersonId PK, Firsname, Lastname
FavoriteRestaurants: ID PK, PersonId, RestaurantId
Restaurants: ResaurantId PK, Name
If I have a PersonId, what is the best way to list all this person's favorite restaurant names?
Or how would I do to initialise this Enumerable based on the person's Id using a repository layer?
IEnumerable MyFavoriteRestaurants = ???
I know I could use foreach to loop on the Person.FavoriteRestaurants collections an retrieve each FavoriteRestaurant.Restaurant one by one, but I was wondering if there were a more elegant way to do this in one line of code.
UPDATE
Here is an example of a Person POCO entity class in my project. This code has been generated by a Microsoft template downloaded from here:
http://visualstudiogallery.msdn.microsoft.com/23df0450-5677-4926-96cc-173d02752313/
//------------------------------------------------------------------------------
// <auto-generated>
// This code was generated from a template.
//
// Changes to this file may cause incorrect behavior and will be lost if
// the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------
using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Collections.Specialized;
namespace UpDir.Domain
{
public partial class Person : EntityBase
{
#region Primitive Properties
public virtual int PersonId
{
get;
set;
}
public virtual string Firstname
{
get;
set;
}
public virtual string Middlename
{
get;
set;
}
public virtual string Lastname
{
get;
set;
}
public virtual string Nickname
{
get;
set;
}
public virtual string EncryptedEmail
{
get;
set;
}
public virtual string Photo
{
get;
set;
}
public virtual short StatusId
{
get { return _statusId; }
set
{
if (_statusId != value)
{
if (Status != null && Status.StatusId != value)
{
Status = null;
}
_statusId = value;
}
}
}
private short _statusId;
#endregion
#region Navigation Properties
public virtual ICollection<Member> Members
{
get
{
if (_members == null)
{
var newCollection = new FixupCollection<Member>();
newCollection.CollectionChanged += FixupMembers;
_members = newCollection;
}
return _members;
}
set
{
if (!ReferenceEquals(_members, value))
{
var previousValue = _members as FixupCollection<Member>;
if (previousValue != null)
{
previousValue.CollectionChanged -= FixupMembers;
}
_members = value;
var newValue = value as FixupCollection<Member>;
if (newValue != null)
{
newValue.CollectionChanged += FixupMembers;
}
}
}
}
private ICollection<Member> _members;
public virtual ICollection<Message> Messages
{
get
{
if (_messages == null)
{
var newCollection = new FixupCollection<Message>();
newCollection.CollectionChanged += FixupMessages;
_messages = newCollection;
}
return _messages;
}
set
{
if (!ReferenceEquals(_messages, value))
{
var previousValue = _messages as FixupCollection<Message>;
if (previousValue != null)
{
previousValue.CollectionChanged -= FixupMessages;
}
_messages = value;
var newValue = value as FixupCollection<Message>;
if (newValue != null)
{
newValue.CollectionChanged += FixupMessages;
}
}
}
}
private ICollection<Message> _messages;
public virtual ICollection<Notification> Notifications
{
get
{
if (_notifications == null)
{
var newCollection = new FixupCollection<Notification>();
newCollection.CollectionChanged += FixupNotifications;
_notifications = newCollection;
}
return _notifications;
}
set
{
if (!ReferenceEquals(_notifications, value))
{
var previousValue = _notifications as FixupCollection<Notification>;
if (previousValue != null)
{
previousValue.CollectionChanged -= FixupNotifications;
}
_notifications = value;
var newValue = value as FixupCollection<Notification>;
if (newValue != null)
{
newValue.CollectionChanged += FixupNotifications;
}
}
}
}
private ICollection<Notification> _notifications;
public virtual Status Status
{
get { return _status; }
set
{
if (!ReferenceEquals(_status, value))
{
var previousValue = _status;
_status = value;
FixupStatus(previousValue);
}
}
}
private Status _status;
public virtual ICollection<UpDirEmail> FromEmails
{
get
{
if (_fromEmails == null)
{
var newCollection = new FixupCollection<UpDirEmail>();
newCollection.CollectionChanged += FixupFromEmails;
_fromEmails = newCollection;
}
return _fromEmails;
}
set
{
if (!ReferenceEquals(_fromEmails, value))
{
var previousValue = _fromEmails as FixupCollection<UpDirEmail>;
if (previousValue != null)
{
previousValue.CollectionChanged -= FixupFromEmails;
}
_fromEmails = value;
var newValue = value as FixupCollection<UpDirEmail>;
if (newValue != null)
{
newValue.CollectionChanged += FixupFromEmails;
}
}
}
}
private ICollection<UpDirEmail> _fromEmails;
public virtual ICollection<UpDirEmail> ToEmails
{
get
{
if (_toEmails == null)
{
var newCollection = new FixupCollection<UpDirEmail>();
newCollection.CollectionChanged += FixupToEmails;
_toEmails = newCollection;
}
return _toEmails;
}
set
{
if (!ReferenceEquals(_toEmails, value))
{
var previousValue = _toEmails as FixupCollection<UpDirEmail>;
if (previousValue != null)
{
previousValue.CollectionChanged -= FixupToEmails;
}
_toEmails = value;
var newValue = value as FixupCollection<UpDirEmail>;
if (newValue != null)
{
newValue.CollectionChanged += FixupToEmails;
}
}
}
}
private ICollection<UpDirEmail> _toEmails;
public virtual ICollection<UpDirEvent> UpDirEvents
{
get
{
if (_upDirEvents == null)
{
var newCollection = new FixupCollection<UpDirEvent>();
newCollection.CollectionChanged += FixupUpDirEvents;
_upDirEvents = newCollection;
}
return _upDirEvents;
}
set
{
if (!ReferenceEquals(_upDirEvents, value))
{
var previousValue = _upDirEvents as FixupCollection<UpDirEvent>;
if (previousValue != null)
{
previousValue.CollectionChanged -= FixupUpDirEvents;
}
_upDirEvents = value;
var newValue = value as FixupCollection<UpDirEvent>;
if (newValue != null)
{
newValue.CollectionChanged += FixupUpDirEvents;
}
}
}
}
private ICollection<UpDirEvent> _upDirEvents;
#endregion
#region Association Fixup
private void FixupStatus(Status previousValue)
{
if (previousValue != null && previousValue.People.Contains(this))
{
previousValue.People.Remove(this);
}
if (Status != null)
{
if (!Status.People.Contains(this))
{
Status.People.Add(this);
}
if (StatusId != Status.StatusId)
{
StatusId = Status.StatusId;
}
}
}
private void FixupMembers(object sender, NotifyCollectionChangedEventArgs e)
{
if (e.NewItems != null)
{
foreach (Member item in e.NewItems)
{
item.Person = this;
}
}
if (e.OldItems != null)
{
foreach (Member item in e.OldItems)
{
if (ReferenceEquals(item.Person, this))
{
item.Person = null;
}
}
}
}
private void FixupMessages(object sender, NotifyCollectionChangedEventArgs e)
{
if (e.NewItems != null)
{
foreach (Message item in e.NewItems)
{
item.Person = this;
}
}
if (e.OldItems != null)
{
foreach (Message item in e.OldItems)
{
if (ReferenceEquals(item.Person, this))
{
item.Person = null;
}
}
}
}
private void FixupNotifications(object sender, NotifyCollectionChangedEventArgs e)
{
if (e.NewItems != null)
{
foreach (Notification item in e.NewItems)
{
item.Person = this;
}
}
if (e.OldItems != null)
{
foreach (Notification item in e.OldItems)
{
if (ReferenceEquals(item.Person, this))
{
item.Person = null;
}
}
}
}
private void FixupFromEmails(object sender, NotifyCollectionChangedEventArgs e)
{
if (e.NewItems != null)
{
foreach (UpDirEmail item in e.NewItems)
{
item.FromPerson = this;
}
}
if (e.OldItems != null)
{
foreach (UpDirEmail item in e.OldItems)
{
if (ReferenceEquals(item.FromPerson, this))
{
item.FromPerson = null;
}
}
}
}
private void FixupToEmails(object sender, NotifyCollectionChangedEventArgs e)
{
if (e.NewItems != null)
{
foreach (UpDirEmail item in e.NewItems)
{
item.ToPerson = this;
}
}
if (e.OldItems != null)
{
foreach (UpDirEmail item in e.OldItems)
{
if (ReferenceEquals(item.ToPerson, this))
{
item.ToPerson = null;
}
}
}
}
private void FixupUpDirEvents(object sender, NotifyCollectionChangedEventArgs e)
{
if (e.NewItems != null)
{
foreach (UpDirEvent item in e.NewItems)
{
item.Person = this;
}
}
if (e.OldItems != null)
{
foreach (UpDirEvent item in e.OldItems)
{
if (ReferenceEquals(item.Person, this))
{
item.Person = null;
}
}
}
}
#endregion
}
}
You don't need to think too much about that, EF will do it for you if you have defined your entity classes correct way like this,
Public class Person{
public int PersonId {get;set;}
public string Firsname{get;set;}
....
public virtual IList<Resturent> Resturents {get;set;}
}
Public class Restaurant{
public int ResaurantId {get;set;}
public string Name{get;set;}
....
public virtual IList<Resturent> People{get;set;}
}
Then you can simply access person.Restaurants to get all restaurants.
I finally figured it out. This is how I am doing it:
IEnumerable<Restaurants> MyFavoriteRestaurants = person.FavoriteRestaurants.Select(m => m.Restaurants);
how can i do the code
static string BuildMenu(List<Menu> menu, int? parentId)
{
foreach (var item in menu.Where(i => i.ParentMenu == parentId || i.ParentMenu.MenuId == parentId).ToList())
{
}
}
return BuildMenu(menuList,null);
so if parentId==null then return only records i => i.ParentMenu == null but when parentId is >0 then return records with i.ParentMenu.MenuId == parentId
You could do that in a single statement, probably something like this
var query = from menu in menus
where (parentId == null ? menu.ParentMenu == null : menu.ParentMenu != null && menu.ParentMenu.MenuId == parentId)
select menu;
But I think it would be more readable by breaking it up like the following
var query = menus.AsEnumerable();
if (parentId.HasValue)
query = query.Where(m => m.ParentMenu != null && m.ParentMenu.MenuId == parentId);
else
query = query.Where(m => m.ParentMenu == null);
Full example:
public class Menu
{
public Menu ParentMenu { get; set; }
public int MenuId { get; set; }
}
...
static void Main(string[] args)
{
List<Menu> menus = new List<Menu>();
for (int i = 0; i < 4; i++)
{
menus.Add(new Menu() { MenuId = i });
}
menus[2].ParentMenu = menus[0];
menus[3].ParentMenu = menus[1];
Console.WriteLine(BuildMenu(menus, 1));
Console.Read();
}
static string BuildMenu(List<Menu> menus, int? parentId)
{
var query = menus.AsEnumerable();
if (parentId.HasValue)
query = query.Where(m => m.ParentMenu != null && m.ParentMenu.MenuId == parentId);
else
query = query.Where(m => m.ParentMenu == null);
StringBuilder builder = new StringBuilder();
foreach (Menu menu in query)
{
// build your string
builder.Append(menu.MenuId + ";");
}
return builder.ToString();
}