How to remove objects from generic List by property value

Having two generic lists of type List<MyClass>, how do I remove from List1 all the instances of List2, matching a property?

This is the setup. I have a class:

public class MyClass
{
    public int MyValue { get; set; }
    public int MyOtherValue { get; set; }
}

And two lists:

List<MyClass> list1 = new List<MyClass>();
list1.Add(new MyClass() { MyValue = 1, MyOtherValue = 10 });
list1.Add(new MyClass() { MyValue = 2, MyOtherValue = 20 });
list1.Add(new MyClass() { MyValue = 3, MyOtherValue = 30 });
list1.Add(new MyClass() { MyValue = 4, MyOtherValue = 40 });

List<MyClass> list2 = new List<MyClass>();
list2.Add(new MyClass() { MyValue = 2, MyOtherValue = 50 });
list2.Add(new MyClass() { MyValue = 3, MyOtherValue = 60 });

I want to remove all list2 instances from list1 matching on MyValue property.

WCF selfhosting helper

A simple wrapper for hosting wcf services that works with both service references and web references.

WcfServiceHelper.Instance.StartService<MyService, IMyService>(new ServerConf());

More can be done in terms of configuration and a StopService method is missing. That is left for the reader (or untill I need it in my app).

Selfhosting WCF on win2008

If you host a WCF service as a non-administrator user on Windows 2008 (and Vista) you may get this error even if you are member of the admin groups:

HTTP could not register URL http://+:8000/. Your process does not have access rights to this namespace (see http://go.microsoft.com/fwlink/?LinkId=70353 for details)

Solution: Log in as administrator and fire:

netsh http add urlacl url=http://+:8000/ user=DOMAIN\UserName

Rotate Zune HD screen to landscape

When developing applications for the Zune HD, you might need to be able to rotate your display to landscape mode. To achieve this easily just make a Pre and Post Draw action ( BeginDraw and EndDraw ), where you manipulate the Viewport. This way you can develop the entire program in horizotal and then rotate it afterwards.

public class LandscapeZuneGame : Game
{
   private RenderTarget2D renderTarget;
   private SpriteBatch spriteBatch;

   public LandscapeZuneGame()
   {
      new GraphicsDeviceManager(this)
      {
         PreferredBackBufferWidth = 480,
         PreferredBackBufferHeight = 272
      };

      IsMouseVisible = true;
   }
   
   protected override void LoadContent()
   {
      renderTarget = new RenderTarget2D(GraphicsDevice, 480, 272, 1, SurfaceFormat.Color);
      spriteBatch = new SpriteBatch(GraphicsDevice);
      base.LoadContent();
   }

   // override BeginDraw so we can set the render target and Viewport before
   // any game drawing occurs.
   protected override bool BeginDraw()
   {
      if (base.BeginDraw())
      {
         GraphicsDevice.SetRenderTarget(0, renderTarget);
         GraphicsDevice.Viewport = new Viewport
         {
            X = 0,
            Y = 0,
            Width = 480,
            Height = 272,
            MinDepth = GraphicsDevice.Viewport.MinDepth,
            MaxDepth = GraphicsDevice.Viewport.MaxDepth
         };
         return true;
      }
      return false;
   }

   // override EndDraw to handle unsetting the render target, resetting the Viewport,
   // and drawing the render target's contents to the screen
   protected override void EndDraw()
   {
      GraphicsDevice.SetRenderTarget(0, null);
      GraphicsDevice.Viewport = new Viewport
      {
         X = 0,
         Y = 0,
         Width = 272,
         Height = 480,
         MinDepth = GraphicsDevice.Viewport.MinDepth,
         MaxDepth = GraphicsDevice.Viewport.MaxDepth
      };

      GraphicsDevice.Clear(Color.Black);
      spriteBatch.Begin();
      spriteBatch.Draw(
         renderTarget.GetTexture(),
         new Vector2(136f, 240f),
         null,
         Color.White,
         MathHelper.PiOver2,
         new Vector2(240f, 136f),
         1f,
         SpriteEffects.None,
         0);

      spriteBatch.End();
      base.EndDraw();
   }
}

Thanks to Nick Gravelyn for the great and easy solution

WPF Databinding Enum with nice descriptions

I have an Enum that I want to databind to a wpf drop down box. But I want to represent the enum with some nice descriptions instead of Enum.ToString().

1) The enum with the nice descriptions: MyEnum.cs

    public enum MyEnum
    {
        [Description("Default value")] // Default value if enum is nullable and used in databinding
        DefaultValue,
        [Description("Value1 description")]
        Value1,
        [Description("Value2 description")]
        Value2
    }

Method with a variable number of parameters

When you need to create a method that handles an undefined number of parameters, one way to define it is by using an Array or list. Like this:

private void Method( string[] arguments )
{
    //...
}

This, however, have a semantic inconvenience when called:

Method( new string[] {  “a”, “b”, “c” };

To overcome this, use params before the string[] identifier, like this

private void Method( params string[] arguments )
{
    //...
}

Now you can call the Method a bit cleaner, making your code more readable:

Method(“a”, ”b”, ”c”);

Find index in list of objects

If you have an object in a list of these objects, you can find the index of the list by:

int index = listOfObjects.IndexOf(testObject);

But that only goes if the testObject reference is in the listOfObjects. If the object is not in the list, but you want to find the index based on a property, do this:

List<myObject> listOfObjects = new List<myObject>();
listOfObjects.Add(new myObject() { Name = "obj 1" });
listOfObjects.Add(new myObject() { Name = "obj 2" });

myObject testObject = new myObject() { Name= "obj 1"};

int index = listOfObjects.Select((s, i) => new { S = s, Index = i }).Where(i => i.S.Name == testObject.Name).First().Index;

Of cause you have to be shure that the testObject is in the list or you will get a exception.

Converting Nullable<int> to Nullable<Enum>

Here is an example on how you identify a Nullable enum and convert an Nullable<int> (int? ) to Nullable<Enum> ( Enum? ).

// type = typeof(MyEnum);

if (type.GetGenericTypeDefinition() == typeof(Nullable<>))
{
    if (type.GetGenericArguments().Length > 0 && type.GetGenericArguments()[0].IsEnum)
    {
        int? intValue = 1;
        if (intValue.HasValue)
        {
            TypeConverter convert = TypeDescriptor.GetConverter(type);
            return convert.ConvertFrom(intValue.Value + "");
        }
        return null;
    }
}

Technorati Tags: C#,nullable,enum,int?,enum?,Nullable<enum>,Nullable<int>

“Casting” list to observablecollection

Easy as pie without for loops:

List<string> myList = new List<string>();
ObservableCollection<string> myObs = new ObservableCollection<string>();

myList.ForEach(i => myObs.Add(i));

LINQ MADNESS !!

Get a list over CountryName doubles in a list of Countries.

List<CountryInfo> test = (from cX in countryInfoList
                        from cY in countryInfoList
                        where cX != cY && cX.CountryName.ToLower() == cY.CountryName.ToLower()
                        select cX ).ToList();

This is almost too simple

Technorati Tags: C#,LINQ,double check