Put very simply:

User controls are a way of making a custom, reusable component. A user control can contain other controls but must be hosted by a form.

Windows forms are the container for controls, including user controls. While it contains many similar attributes as a user control, it&#39;s primary purpose is to host controls.

They have a *lot* in common, they are both derived from ContainerControl.  UserControl however is designed to be a child window, it needs to be placed in a container.  Form was designed to be a top-level window without a parent.

You can actually turn a Form into a child window by setting its TopLevel property to false:

    public partial class Form1 : Form {
        public Form1() {
            InitializeComponent();
            var child = new Form2();
            child.TopLevel = false;
            child.Location = new Point(10, 5);
            child.Size = new Size(100, 100);
            child.BackColor = Color.Yellow;
            child.FormBorderStyle = FormBorderStyle.None;
            child.Visible = true;
            this.Controls.Add(child);
        }
    }


A windows form is a container for user controls.

The biggest difference is form.show gives a different window while usercontrol doesnt have feature like popping up without a parent. Rest things are same in both the controls like beind derived from Scrollablecontrol.

I&#39;ve seen the concept of &#39;opaque types&#39; thrown around a bit but I really haven&#39;t found a succinct answer as to what defines an opaque type in C and more importantly what problems they allow us to solve with their existence.  Thanks





What defines an opaque type in C, and when are they necessary and/or useful?

I&#39;ve [asked a simlar question on Meta Stack Overflow][1], but that deals specifically with whether or not [Lucene.NET][2] is used on Stack&amp;nbsp;Overflow.

The purpose of the question here is more of a hypotetical, as to what approaches one would make if they were to use Lucene.NET as a basis for in-site search and other factors in a site *like* Stack&amp;nbsp;Overflow [SO]. 

As per the entry on the Stack&amp;nbsp;Overflow blog titled &quot;[SQL 2008 Full-Text Search Problems][3]&quot; there was a **strong** indication that Lucene.NET was being considered at some point, but it appears that is definitely not the case, as per the comment by [Geoff Dalgas][4] on February 19th 2010:

&gt; Lucene.NET is not being used for Stack
&gt; Overflow - we are using SQL Server
&gt; Full Text indexing. Search is an area
&gt; where we continue to make minor
&gt; tweaks.

So my question is, how would one utilize Lucene.NET into a site which has the same semantics of Stack&amp;nbsp;Overflow?

Here is some background and what I&#39;ve done/thought about so far (yes, I&#39;ve been implementing most of this and search is the last aspect I have to complete):

**Technologies:**

- [ASP.NET MVC][5]
- [SQL Server 2008][6]
- [.NET 3.5][7]
- [C# 3.0][8]

And of course, the star of the show, Lucene.NET.

The intention is also to move to .NET/C# 4.0 ASAP. While I don&#39;t think it&#39;s a game-changer, it should be noted.

Before getting into aspects of Lucene.NET, it&#39;s important to point out the SQL Server 2008 aspects of it, as well as the models involved.

**Models**

This system has more than one primary model type in comparison to Stack&amp;nbsp;Overflow. Some examples of these models are:

- Questions: These are questions that people can ask. People can reply to questions, just like on Stack&amp;nbsp;Overflow.
- Notes: These are one-way projections, so as opposed to a question, you are making a statement about content.  People can&#39;t post replies to this.
- Events: This is data about a real-time event.  It has location information, date/time information.

The important thing to note about these models:

- They all have a Name/Title (text) property and a Body (HTML) property (the formats are irrelevant, as the content will be parsed appropriately for analysis).
- Every instance of a model has a unique URL on the site

Then there are the things that Stack&amp;nbsp;Overflow provides which IMO, are decorators to the models. These decorators can have different cardinalities, either being one-to-one or one-to-many:

- Votes: Keyed on the user
- Replies: Optional, as an example, see the Notes case above
- Favorited: Is the model listed as a favorite of a user?
- Comments: (optional)
- Tag Associations: Tags are in a separate table, so as not to replicate the tag for each model.  There is a link between the model and the tag associations table, and then from the tag associations table to the tags table.

And there are supporting tallies which in themselves are one-to-one decorators to the models that are keyed to them in the same way (usually by a model id type and the model id):

- Vote tallies: Total postive, negative votes, [Wilson Score interval][9] (this is important, it&#39;s going to determine the confidence level based on votes for an entry, for the most part, assume the lower bound of the Wilson interval).

Replies (answers) are models that have most of the decorators that most models have, they just don&#39;t have a title or url, and whether or not a model has a reply is optional.  If replies are allowed, it is of course a one-to-many relationship.

**SQL Server 2008**

The tables pretty much follow the layout of the models above, with separate tables for the decorators, as well as some supporting tables and views, stored procedures, etc.

It should be noted that the decision to not use full-text search is based primarily on the fact that it doesn&#39;t normalize scores like Lucene.NET. I&#39;m open to suggestions on how to utilize text-based search, but I will have to perform searches across multiple model types, so keep in mind I&#39;m going to need to normalize the score *somehow*.

**Lucene.NET**

This is where the big question mark is. Here are my thoughts so far on Stack&amp;nbsp;Overflow functionality as well as how and what I&#39;ve already done.

**Indexing**

**Questions/Models** 

I believe each model should have an index of its own containing a unique id to quickly look it up based on a Term instance of that id (indexed, not analyzed).

In this area, I&#39;ve considered having Lucene.NET analyze each question/model and each reply individually.  So if there was one question and five answers, the question and each of the answers would be indexed as one unit separately.  

The idea here is that the relevance score that Lucene.NET returns would be easier to compare between models that project in different ways (say, something without replies).

As an example, a question sets the subject, and then the answer elaborates on the subject.

For a note, which doesn&#39;t have replies, it handles the matter of presenting the subject and then elaborating on it.

I believe that this will help with making the relevance scores more relevant to each other.

**Tags**

Initially, I thought that these should be kept in a separate index with multiple fields which have the ids to the documents in the appropriate model index. Or, if that&#39;s too large, there is an index with just the tags and another index which maintains the relationship between the tags index and the questions they are applied to. This way, when you click on a tag (or use the URL structure), it&#39;s easy to see in a progressive manner that you only have to &quot;buy into&quot; if you succeed:

- If the tag exists
- Which questions the tags are associated with
- The questions themselves

However, in practice, doing a query of all items based on tags (like clicking on a tag in Stack&amp;nbsp;Overflow) is *extremely easy* with SQL Server 2008. Based on the model above, it simply requires a query such as:

    select
         m.Name, m.Body
    from
        Models as m
            left outer join TagAssociations as ta on
                ta.ModelTypeId = &lt;fixed model type id&gt; and
                ta.ModelId = m.Id
            left outer join Tags as t on t.Id = ta.TagId
    where
        t.Name = &lt;tag&gt;

And since certain properties are shared across all models, it&#39;s easy enough to do a `UNION` between different model types/tables and produce a consistent set of results.

This would be analagous to a [`TermQuery`][10] in Lucene.NET (I&#39;m referencing the [Java documentation][11] since it&#39;s comprehensive, and Lucene.NET is meant to be a line-by-line translation of [Lucene][12], so all the documentation is the same).

The issue that comes up with using Lucene.NET here is that of sort order. The relevance score for a TermQuery when it comes to tags is irrelevant. It&#39;s either 1 or 0 (it either has it or it doesn&#39;t).

At this point, the confidence score (Wilson score interval) comes into play for ordering the results.

This score could be stored in Lucene.NET, but in order to sort the results on this field, it would rely on the values being stored in the field cache, which is something I really, really want to avoid. For a large number of documents, the field cache can grow very large (the Wilson score is a double, and you would need one double for every document, that can be one large array).

Given that I can change the SQL statement to order based on the Wilson score interval like this:

    select
         m.Name, m.Body
    from
        Models as m
            left outer join TagAssociations as ta on
                ta.ModelTypeId = &lt;fixed model type id&gt; and
                ta.ModelId = m.Id
            left outer join Tags as t on t.Id = ta.TagId
            left outer join VoteTallyStatistics as s on
                s.ModelTypeId = ta.ModelTypeId and
                s.ModelId = ta.ModelId
    where
        t.Name = &lt;tag&gt;
    order by
        --- Use Id to break ties.
        s.WilsonIntervalLowerBound desc, m.Id

It seems like an easy choice to use this to handle the piece of Stack&amp;nbsp;Overflow functionality &quot;get all items tagged with &amp;lt;tag&amp;gt;&quot;.

**Replies**

Originally, I thought this is in a separate index of its own, with a key back into the Questions index.

I think that there should be a combination of each model and each reply (if there is one) so that relevance scores across different models are more &quot;equal&quot; when compared to each other.

This would of course bloat the index.  I&#39;m somewhat comfortable with that right now.

Or, is there a way to store say, the models and replies as individual documents in Lucene.NET and then take both and be able to get the relevance score for a query treating *both documents as one*?  If so, then this would be **ideal**.

There is of course the question of what fields would be stored, indexed, analyzed (all operations can be separate operations, or mix-and-matched)? *Just how much would one index?*

What about using special stemmers/porters for spelling mistakes (using Metaphone) as well as synonyms (there is terminology in the community I will service which has it&#39;s own slang/terminology for certain things which has multiple representations)?

**Boost**

This is related to indexing of course, but I think it merits it&#39;s own section.

Are you **boosting** fields and/or documents? If so, how do you boost them? Is the boost constant for certain fields? Or is it recalculated for fields where vote/view/favorite/external data is applicable.

For example, in the document, does the title get a boost over the body? If so, what boost factors do you think work well? What about tags?

The thinking here is the same as it is along the lines of Stack&amp;nbsp;Overflow. Terms in the document have relevance, but if a document is tagged with the term, or it is in the title, then it should be boosted.

[Shashikant Kore][13] suggests a document structure like this:

- Title
- Question
- Accepted Answer (Or highly voted answer if there is no accepted answer)
- All answers combined

And then using boost but not based on the raw vote value. I believe I have that covered with the Wilson Score interval.

The question is, should the boost be applied to the entire document? I&#39;m leaning towards no on this one, because it would mean I&#39;d have to reindex the document each time a user voted on the model.

**Search for Items Tagged &lt;tag&gt;**

I originally thought that when querying for a tag (by specifically clicking on one or using the URL structure for looking up tagged content), that&#39;s a simple TermQuery against the tag index for the tag, then in the associations index (if necessary) then back to questions, Lucene.NET handles this really quickly.

However, given the notes above regarding how easy it is to do this in SQL Server, I&#39;ve opted for that route when it comes to searching tagged items.

**General Search**

So now, the most outstanding question is when doing a general phrase or term search against content, what and how do you integrate other information (such as votes) in order to determine the results in the proper order? For example, when performing this search on [ASP.NET MVC on Stack Overflow][14], these are the tallies for the top five results (when using the relevance tab):

        q votes answers accepted answer votes asp.net highlights mvc highlights
        ------- ------- --------------------- ------------------ --------------
             21      26                    51                  2              2
             58      23                    70                  2              5
             29      24                    40                  3              4
             37      15                    25                  1              2
             59      23                    47                  2              2

Note that the highlights are only in the title and abstract on the results page and are only minor indicators as to what the true term frequency is in the document, title, tag, reply (however they are applied, which is another good question).

How is all of this brought together?  

At this point, I know that Lucene.NET will return a normalized relevance score, and the vote data will give me a Wilson score interval which I can use to determine the confidence score.

**How should I look at combining tese two scores to indicate the sort order of the result set based on relevance and confidence?**

It is obvious to me that there should be *some* relationship between the two, but what that relationship should be evades me at this point.  I know I have to refine it as time goes on, but I&#39;m really lost on this part.

My initial thoughts are if the relevance score is beween 0 and 1 and the confidence score is between 0 and 1, then I could do something like this:

    1 / ((e ^ cs) * (e ^ rs))

This way, one gets a normalized value that approaches 0 the more relevant and confident the result is, and it can be sorted on that.

The main issue with that is that if boosting is performed on the tag and or title field, then the relevance score is outside the bounds of 0 to 1 (the upper end becomes unbounded then, and I don&#39;t know how to deal with that).

Also, I believe I will have to adjust the confidence score to account for vote tallies that are completely negative.  Since vote tallies that are completely negative result in a Wilson score interval with a lower bound of 0, something with -500 votes has the same confidence score as something with -1 vote, or 0 votes.

Fortunately, the upper bound decreases from 1 to 0 as negative vote tallies go up. I could change the confidence score to be a range from -1 to 1, like so:

    confidence score = votetally &lt; 0 ? 
        -(1 - wilson score interval upper bound) :
        wilson score interval lower bound

The problem with this is that plugging in 0 into the equation will rank all of the items with zero votes below those with negative vote tallies.

To that end, I&#39;m thinking if the confidence score is going to be used in a reciprocal equation like above (I&#39;m concerned about overflow obviously), then it needs to be reworked to always be positive.  One way of achieving this is:

    confidence score = 0.5 + 
        (votetally &lt; 0 ? 
            -(1 - wilson score interval upper bound) :
            wilson score interval lower bound) / 2

My other concerns are how to actually perform the calculation given Lucene.NET and SQL Server.  I&#39;m hesitant to put the confidence score in the Lucene index because it requires use of the field cache, which can have a huge impact on memory consumption (as mentioned before).

An idea I had was to get the relevance score from Lucene.NET and then using a [table-valued parameter][15] to stream the score to SQL Server (along with the ids of the items to select), at which point I&#39;d perform the calculation with the confidence score and then return the data properly ordred.

As stated before, there are a lot of other questions I have about this, and the answers have started to frame things, and will continue to expand upon things as the question and answers evovled.

  [1]: https://meta.stackexchange.com/questions/39950/how-is-lucene-net-utilized-on-stackoverflow-if-at-all
  [2]: http://incubator.apache.org/lucene.net/
  [3]: https://blog.stackoverflow.com/2008/11/sql-2008-full-text-search-problems/
  [4]: https://meta.stackoverflow.com/users/2/geoff-dalgas
  [5]: http://www.asp.net/mvc/
  [6]: http://msdn.microsoft.com/sqlserver
  [7]: http://msdn.microsoft.com/netframework
  [8]: http://msdn.microsoft.com/netframework
  [9]: http://en.wikipedia.org/wiki/Binomial_proportion_confidence_interval#Wilson_score_interval
  [10]: http://lucene.apache.org/java/2_4_0/api/org/apache/lucene/search/TermQuery.html
  [11]: http://lucene.apache.org/java/3_0_1/
  [12]: http://lucene.apache.org/java/docs/
  [13]: https://stackoverflow.com/users/77308/shashikant-kore
  [14]: https://stackoverflow.com/search?q=asp.net+mvc
  [15]: http://msdn.microsoft.com/en-us/library/bb510489.aspx


How would one use Lucene.NET to help implement search on a site like Stack Overflow?

What is the difference between a user control and a windows form in Visual Studio - C#?

User Control vs. Windows Form

<p>What is the difference between a user control and a windows form in Visual Studio - C#?</p>


Ok, what I have: 

Visual Studio 2010 RC, W7 x64, started a new project type of Silverlight application. Hosting the Silverlight application in a ASP.NET Web Application Project. Silverlight Version 3.0.
Added a LinqToSQL Class, a WCF Service, a Winform Tester Application (Project in the Solution) and a few Classes (also as Projects in the Solution).

Yesterday, suddenly I got the &#39;The breakpoint will not currently be hit. No symbols have been loaded for this document.&#39; message to appear in the IDE, but it only affects the Web Appliaction, I can debug the Silverlight and the Winform App.
 
What I tried / did to get rid of the message:
 
- Reset Visual Studio Settings
- removed all files in every \Temporary ASP.NET Files Folder (there is one for each 32bit/64bit and for Framework 2.0 and 4.0)
- tried to debug using Visual Studio Integrated Web server - normally I use IIS, in the project output of the solution I deleted every obj and bin folders in every project folder
- created a new solution and added all the projects to this new solution
- deleted the solution suo file
- created a new ASP.NET Web Application to test if it is a VS-installation issue =&gt; I can debug this new project/solution
- rebooted the machine several times
- repaired the vs.net installation
- did an IISReset
- removed the Web App from IIS
- used the Create Virtual Directory Button under Project Properties of the Web App to create a new Web App in IIS
- changed the Framework Version of every project from 3.5 to 4.0
- Opened the Solution on my second machine =&gt; same behavior
- crawled Microsoft Connect for bugs / similar issues
- SPENT 7 HOURS. 

So, this happens the 2nd time in my life. last time I solved it by deleting Temporary ASP.NET Files Folder, but this time I need your help.

The breakpoint will not currently be hit. No symbols have been loaded for this document in a Silverlight application

I&#39;m adding a new method to a class that implements an interface, and I like to use the &quot;Extract Interface&quot; refactoring and just add the method to the interface. But it doesn&#39;t seem like ReSharper supports adding a method signature to an already existing interface.

It feels like I&#39;m missing something, I&#39;m sure it can be done somehow. Maybe I should add the method signature to the interface first, but this is the way I&#39;m working sometimes. Am I missing some shortcut, feature or using ReSharper wrong? 

Extract method to already existing interface with ReSharper

What is the difference between `ArrayList` and `List&lt;&gt;` in C#? 

Is it only that `List&lt;&gt;` has a type while `ArrayList` doesn&#39;t?

ArrayList vs List&lt;&gt; in C#

I am reading CLR via C# by Jeffery Richter and it says a struct is a value type and cannot be inherited.

Are there any technical or philosophical reasons?


ADD 1 - 5:53 PM 11/11/2020
---
*Every decision, no matter how reasonable or accidental it may look, has its impact, subtle or profound. We try to decouple things, sometimes by creating new coupling...*

Why C# structs cannot be inherited?

`Request[&quot;key&quot;]` vs `Request.Params[&quot;key&quot;]` vs `Request.QueryString[&quot;key&quot;]`

Which method do you seasoned programmers use? and why?

Request[&quot;key&quot;] vs Request.Params[&quot;key&quot;] vs Request.QueryString[&quot;key&quot;]

I have multiple projects in a single Visual Studio (2008) solution.  
I just discovered that each of these projects uses a same GUID, so in the solution file it looks like this:

    Project(&quot;{FAE04EC0-F103-D311-BF4B-00C04FCBFE97}&quot;) = &quot;Pro1&quot;, &quot;Pro1\Pro1.csproj&quot;, &quot;{...}&quot;
    Project(&quot;{FAE04EC0-F103-D311-BF4B-00C04FCBFE97}&quot;) = &quot;Pro2&quot;, &quot;Pro2\Pro2.csproj&quot;, &quot;{...}&quot;

Do I have to change these GUIDs so they&#39;re unique and what are they used for?


What are the project GUIDs in a Visual Studio solution file used for?

if I define my constant varibles in my header like this...

    extern const double PI = 3.1415926535;
    extern const double PI_under_180 = 180.0f / PI;
    extern const double PI_over_180 = PI/180.0f;

I get the following error

    1&gt;MyDirectX.obj : error LNK2005: &quot;double const PI&quot; (?PI@@3NB) already defined in main.obj
    1&gt;MyDirectX.obj : error LNK2005: &quot;double const PI_under_180&quot; (?PI_under_180@@3NB) already defined in main.obj
    1&gt;MyDirectX.obj : error LNK2005: &quot;double const PI_over_180&quot; (?PI_over_180@@3NB) already defined in main.obj
    1&gt;MyGame.obj : error LNK2005: &quot;double const PI&quot; (?PI@@3NB) already defined in main.obj
    1&gt;MyGame.obj : error LNK2005: &quot;double const PI_under_180&quot; (?PI_under_180@@3NB) already defined in main.obj
    1&gt;MyGame.obj : error LNK2005: &quot;double const PI_over_180&quot; (?PI_over_180@@3NB) already defined in main.obj

but If I remove those constants from the header and put them in the document that is including the header like this...

    const double PI = 3.1415926535;
    const double PI_under_180 = 180.0f / PI;
    const double PI_over_180 = PI/180.0f;

It works

Does anyone have Idea what I might be doing wrong ??

Thanks

constant variables not working in header

Being new to VS, how may I think of these two concepts, what is the difference?

Visual Studio Project vs. Solution

Currently I have solution A that contains a domain layer base and solution B that references the binaries from solution A. Is there a way to debug straight through from one to the other with two instances of Visual Studio open (one for each solution)?

I&#39;ve read that you can just add the existing projects from solution A to solution B. Is there another solution that works? I&#39;ve tried directly attaching solution A to what the running executable in solution B, but it won&#39;t let me attach multiple debuggers to the same application.

I should note that when I step into a piece of it, it automatically brings up the code from solution A within solution B&#39;s instance of Visual Studio to debug in. I suppose this is acceptable, but you can&#39;t just set arbitrary breakpoints and wait for the code to hit them this way.


Debugging through different solutions in Visual Studio

This DLL is added by default in Visual Studio 2010 projects. What is this new assembly used for? It does not seem to contain much after looking at it using Reflector and Google does not seem to have much to say about it either.

What is Microsoft.csharp.dll in .NET 4.0

In my application I want to show a login form first and then the main form if the login has been successful. Currently I&#39;m doing it something like this:

    var A = new LoginForm();
    if ( A.ShowDialog() == DialogResult.OK )
        Application.Run(new MainForm());

But then I started wondering - what&#39;s the point of the `Application.Run()`? Why not just do `(new MainForm()).ShowDialog()` as well? What&#39;s the difference? And what would be the correct way to achieve what I want?

What&#39;s the difference between Application.Run() and Form.ShowDialog()?

I need to get the list of all printers that connect to computer?

How I can do it in C#, WinForms?

How to get the list of all printers in computer

I have become painfully aware of just how often one needs to write the following code pattern in event-driven GUI code, where

    private void DoGUISwitch() {
        // cruisin for a bruisin&#39; through exception city
        object1.Visible = true;
        object2.Visible = false;
    }

becomes:

    private void DoGUISwitch() {
        if (object1.InvokeRequired) {
            object1.Invoke(new MethodInvoker(() =&gt; { DoGUISwitch(); }));
        } else {
            object1.Visible = true;
            object2.Visible = false;
        }
    }

This is an awkward pattern in C#, both to remember, and to type. Has anyone come up with some sort of shortcut or construct that automates this to a degree? It&#39;d be cool if there was a way to attach a function to objects that does this check without having to go through all this extra work, like a `object1.InvokeIfNecessary.visible = true` type shortcut.

Previous [answers][1] have discussed the impracticality of just calling Invoke() every time, and even then the Invoke() syntax is both inefficient and *still* awkward to deal with.

So, has anyone figured out any shortcuts?


  [1]: https://stackoverflow.com/questions/747210/whats-wrong-with-calling-invoke-regardless-of-invokerequired

Automating the InvokeRequired code pattern

So that it just allows selecting items already inside, but not allow typing/editing the text inside it?



Is it possible to change a Winforms combobox to disable typing into it?

How do you simulate Mouse clicks in C# winforms applications?

Content Type	Original Author	Original Content on Stackoverflow
Question	Arlen Beiler	View Question on Stackoverflow
Solution 1 - C#	Bill Martin	View Answer on Stackoverflow
Solution 2 - C#	Hans Passant	View Answer on Stackoverflow
Solution 3 - C#	Ikke	View Answer on Stackoverflow
Solution 4 - C#	sunnytyra	View Answer on Stackoverflow

User Control vs. Windows Form

C# Problem Overview

C# Solutions

Solution 1 - C#

Solution 2 - C#

Solution 3 - C#

Solution 4 - C#

How would one use Lucene.NET to help implement search on a site like Stack Overflow?

What defines an opaque type in C, and when are they necessary and/or useful?

Attributions