Problem with Linq Contains or comparing two instances of the dbml generated class of my sql table - C# Discussion Boards

I'm not claiming any knowledge of this as I've never used it but I've just read the docs on the RegisterChannel and Unregister channel.

It appears that you may only need to use these methods to add/remove additional http or tcp channels to the registered channels list. By default, there are ones named "http" and "tcp" which is probably what's being used by your app. The registered channels list requires unique names which is why these methods are there in case you need to have more than one of either type.

I may be way off here - as i said I've never used it - but the docs seem to imply this.
Alt Register Channel Page[^]
RegisterChannel[^]
UnregisterChannel[^]

Dave
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)
Visual Basic is not used by normal people so we're not covering it here. (Uncyclopedia)

Yes, I read those docs, and maybe I missed something.
Channels require a number, Port number that is, and not a name.
The client connect through the port number .
And it can do that even if I dont register the channel at the server.

Why do I need to register the channel then?
And most important how do I release the channel?

10x.

I have a manager class which works as a proxy for connecting to mysql database. I have 2 methods in it, ConnectToDatabase and ExecuteQuery.

How should I write the class? Should I make it singleton?

Else, if I initiate the class each time, won't it take delay to connect to database??

Thanks in advance
Anvesh

anveshvm wrote:
Else, if I initiate the class each time, won't it take delay to connect to database??

Initialization of your proxy class will not affect the delay to connect to database. And I don't think you need a singleton implementation here.

Navaneeth

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What about the connection object??

Should I keep the object static for the entire program execution scope.

Or should I connect to the database, each time, I have to execute a query?

anveshvm wrote:
Or should I connect to the database, each time, I have to execute a query?

Yeah. That's the right approach.

anveshvm wrote:
Should I keep the object static for the entire program execution scope.

You can keep it if the object is very expensive to build each time. But if it is a simple proxy class, keeping instance will not give performance difference.

Navaneeth

How to use google | Ask smart questions

thank you...

Hi.
I am currently learning Linq and have some trouble with the Linq Contains function.

Here is what I first tried:

DataClasses1DataContext con = new DataClasses1DataContext(@"myconstring");
bool contains = con.Images.Contains(con.Images.First(n => n.imageID == 2));

I was pretty shure this would work but contains became false.

I then tried this:

Image myImg = con.Images.First(n => n.imageID == 2);
Image myImg3 = con.Images.First(n => n.imageID == 2);

if (myImg.Equals(myImg3))
                Console.WriteLine("hurra");

But this did not work either. The two instances did not equal eachother.
I continued to try with this:

Image myImg2 = new Image
                               {
                                   created = DateTime.Parse("23.05.2008 00:00:00"),
                                   description = "Jalla",
                                   imageID = 2,
                                   name = "test",
                                   searchWords = "halla",
                                   systemID = 1
                               };
            Image myImg4 = new Image
            {
                created = DateTime.Parse("23.05.2008 00:00:00"),
                description = "Jalla",
                imageID = 2,
                name = "test",
                searchWords = "halla",
                systemID = 1
            };

if (myImg2.Equals(myImg4))
                Console.WriteLine("hurra");

But still they did not equal eachother. Only way I got this to work was by adding my img instances to a Array of Images[] and then do contains on this.

Image[] imgs = {myImg, myImg2, myImg3, myImg4};
bool contains = imgs.Contains(myImg2);

This gives contains a true value. So then I tought that this should work:

bool contains = con.Images.ToList().Contains(con.Images.First(n => n.imageID == 2));

But still contains is set to false.

So I am stumped. Anyone got anny sugestions or hints to why this does not work?

I found one workaround, but I still wonder if there is a bether way of doing this. Here is a solution that works:

bool contains = con.Images.ToList().Contains(con.Images.First(n => n.imageID == 2),new checker());

and the checker class:

public class checker : IEqualityComparer<image>
   {



       #region IEqualityComparer<image> Members

       public bool Equals(Image x, Image y)
       {
           if (x.imageID == y.imageID)
               return true;
           else
           {
               return false;
           }
       }

       public int GetHashCode(Image obj)
       {
           return obj.GetHashCode();
       }

       #endregion
   }</image></image>

And I am still verry curious to why this dont work:

Image myImg2 = new Image
                               {
                                   created = DateTime.Parse("23.05.2008 00:00:00"),
                                   description = "Jalla",
                                   imageID = 2,
                                   name = "test",
                                   searchWords = "halla",
                                   systemID = 1
                               };
            Image myImg4 = new Image
            {
                created = DateTime.Parse("23.05.2008 00:00:00"),
                description = "Jalla",
                imageID = 2,
                name = "test",
                searchWords = "halla",
                systemID = 1
            };

if (myImg2.Equals(myImg4))
                Console.WriteLine("hurra");

I see no reason why these two instances should not equal eachother.

Here is the autogenerated Image class if anyone wants to know how that looks:

[Table(Name="dbo.Images")]
	public partial class Image
	{
		
		private int _imageID;
		
		private int _systemID;
		
		private string _name;
		
		private string _description;
		
		private string _searchWords;
		
		private System.DateTime _created;
		
		private System.Nullable<system.datetime> _uppdated;
		
		public Image()
		{
		}
		
		[Column(Storage="_imageID", AutoSync=AutoSync.Always, DbType="Int NOT NULL IDENTITY", IsDbGenerated=true)]
		public int imageID
		{
			get
			{
				return this._imageID;
			}
			set
			{
				if ((this._imageID != value))
				{
					this._imageID = value;
				}
			}
		}
		
		[Column(Storage="_systemID", DbType="Int NOT NULL")]
		public int systemID
		{
			get
			{
				return this._systemID;
			}
			set
			{
				if ((this._systemID != value))
				{
					this._systemID = value;
				}
			}
		}
		
		[Column(Storage="_name", DbType="NVarChar(50) NOT NULL", CanBeNull=false)]
		public string name
		{
			get
			{
				return this._name;
			}
			set
			{
				if ((this._name != value))
				{
					this._name = value;
				}
			}
		}
		
		[Column(Storage="_description", DbType="NVarChar(2000)")]
		public string description
		{
			get
			{
				return this._description;
			}
			set
			{
				if ((this._description != value))
				{
					this._description = value;
				}
			}
		}
		
		[Column(Storage="_searchWords", DbType="NVarChar(2000)")]
		public string searchWords
		{
			get
			{
				return this._searchWords;
			}
			set
			{
				if ((this._searchWords != value))
				{
					this._searchWords = value;
				}
			}
		}
		
		[Column(Storage="_created", DbType="DateTime NOT NULL")]
		public System.DateTime created
		{
			get
			{
				return this._created;
			}
			set
			{
				if ((this._created != value))
				{
					this._created = value;
				}
			}
		}
		
		[Column(Storage="_uppdated", DbType="DateTime")]
		public System.Nullable<system.datetime> uppdated
		{
			get
			{
				return this._uppdated;
			}
			set
			{
				if ((this._uppdated != value))
				{
					this._uppdated = value;
				}
			}
		}
	}</system.datetime></system.datetime>

Continued from "Another" one automation error...[^]

Ok, now, we going some steps forward...

System architecture is as follows: there are number of out-of-process COM servers. Each one uses an in-process server to access .NET interop. So:

[out-of-process COM server No.1] --\
[out-of-process COM server No.2] -- \
........................................................... --> [in-process COM component] --> [.NET interop component]
[out-of-process COM server No.n] ---/

This architecture required because it get possible to set each application with its own configuration provided to .NET component.

From previous attempts we know, that .NET component with satellite assemblies should be placed in working directory of COM application. In my case I need to duplicate them in each COM application. Or to install them to GAC.

So, I have placed all assemblies (including resources) to GAC and... right, I got automation error...
Fuslogvw does not point to some error. All assemblies were found and loaded from GAC successfully (except en-culture resource file that really does not present and embedded - it should not be a case, does not it?)

So the questions are:
- Is there some way to optimize present architecture scheme?
- Why GAC installation does not work?
- Does COM application need some additional permissions to access GAC?

Thanks to all.

modified on Wednesday, January 7, 2009 4:13 AM

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