Just in case if Arabic characters appearing as ????? in your column and if you are using MySql DB along with .NET Provider, 

Check below properties of schema, table and column and connectionstring that use to connect to DB

1. DEFAULT_CHARACTER_SET_NAME = utf8
2. DEFAULT_COLLATION_NAME = utf8_general_ci
3. TABLE_COLLATION = utf8_general_ci
4. COLLATION_NAME = utf8_general_ci
5. CHARACTER_SET_NAME = utf8
6. .NET Connection string set to have = 'charset=utf8'

Connection string example

'datasource=<server>;port=3306;username=<userid>;password=<password>;sslmode=none;database=<dbname>;charset=utf8'

Queries that may help to find above information are 

SELECT * FROM information_schema.SCHEMATA S

WHERE schema_name = "<database-name>";

SELECT * FROM information_schema.`TABLES` T,

information_schema.`COLLATION_CHARACTER_SET_APPLICABILITY` CCSA

WHERE CCSA.collation_name = T.table_collation

AND T.table_schema = "<database-name>"

AND T.table_name = "<table-name>";

SELECT * FROM information_schema.`COLUMNS` C

WHERE table_schema = "<database-name>"

AND table_name = "<table-name>"

AND column_name = "<column-name>";

I have came through below wiki article on Microsoft technet, which have a nice collection of eBooks and articles on Microsoft Technologies.

Download content for SharePoint, Lync, MS Office, SQL Server, System Center, Visual Studio, Web Development (asp.net), Windows Server, Window Azure, Windows Phone and other Microsoft technologies in e-book formats (references, guide, and step-by-step).

E-Book Gallery for Microsoft Technologies

Source: social.technet.microsoft.com/wiki/contents/articles/11608.e-book-gallery-for-microsoft-technologies.aspx (Monica Rush)
Source: mstechtalk.com/collection-of-e-book-and-articles-on-microsoft-technologies/ (Adnan Amin)

If you want to have signin as different user functionality like sharepoint in your asp.net application, following workaround you might be looking for.
After setting your web.config file's 

<authentication mode="Windows" />

and in IIS after remove anonymous authentication and enable windows authentication, have following code snippet where you want to have this functionality

In your aspx page

    <div>You are logged in as <br /> <%=User.Identity.Name%> <br /><br /> 
    <asp:LinkButton ID="lnkSignOut" runat="server" Text="Sign in as different user" onclick="lnkSignOut_Click"></asp:LinkButton>


In your code behind file

 protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        Session["logOutRequested"] = false; //Initialize value. This will be set to true when user will click on sign in as differnet user
    }
}


protected void lnkSignOut_Click(object sender, EventArgs e)
{
    if (null != Session["logOutRequested"] && !Convert.ToBoolean(Session["logOutRequested"])) // Check if user is clicking link first time
    {
        Session["logOutRequested"] = true; //Set value that user want to sign in as differnet user
        Response.StatusCode = 401;
        Response.StatusDescription = "Unauthorized";
        Response.End();
    }
    else
    {
        Session["logOutRequested"] = false; //Initialize value again after user is authenticated with differnet or same user again.
    }
}


Hope this workaround will help.

In case if above workaround is not working, you may try following one
www.roelvanlisdonk.nl/?p=825

This post posted by Vladimir Kuzin on 15th Oct 2009. For Quick reference posted here.

Few weeks ago I was working on project which required data to be encrypted using C# and then decrypted using JavaScript. In my case JavaScript was an internal scripting language, which wasn’t exposed to public so I didn’t have to worry about people accessing encryption keys. Project objective was to encode parameter in URL preventing users from substituting it with sequential numbers.

Research:

At first I’ve decided to use symmetric algorithm and looked online for available JavaScript libraries. In my search I’ve found few AES libraries to choose form. After further analysis it was determined that most people had good luck with slowAES, and I’ve attempted to implement it. After spending some time I was unable to decrypt any data encoded with RijndaelManaged class in C#. Since I had to find solution fast I’ve moved on.

Next I’ve decided to try asymmetric encryption algorithm, and after quick research I went with RSA. After downloading most popular RSA library for JavaScript I’ve run into several issues with its implementation. I was able to use C# to decode everything what was encoded in JavaScript, but it didn’t work when data was flowing in opposite direction. After looking into the issue it appeared that JavaScript library was missing padding, however using patched versionof the library didn’t help.

Solution:

Due to lack of time I’ve decided to use simpler encryption algorithm and went with RC4. After downloading RC4 JavaScriptlibrary I’ve got it to work within minutes. Since there is no such thing as RC4 cryptographic provider in the Security.Cryptography namespace I had to use open source RC4 library.

After encrypting data I’ve also converted it to hex (base 16) in the same way as it was done on the JavaScript RC4 demo page.

Encrypting URL parameter with RC4 didn’t completely meet the objective, since it still was possible for users to use sequential numbers. Take a look at example of encrypted data below:

Notice that only last digit of the encrypted data has changed, therefore substituting it with sequential numbers will cause an issue. To solve this I’ve added random prefix and suffix blocks to data before encrypting. Prefix and suffix blocks consisted from random letters and were anywhere between 10 and 25 characters in length. Now data looked like this:

Every time encrypted value is changing, since it’s generated from new random data. After transferring and decrypting this data on the JavaScript side I’ve spited string by semicolon to get the actual parameter value.

I am sure there are different and possibly better solutions somewhere out there, but this one worked for my client and was implemented within a small project budget.

This is post is from original Post @ vkuzin.com/post/Passing-encrypted-data-between-C-and-JavaScript.aspx

Accessing JD Edwards Data on iSeries or AS/400 from a ASP.NET

Facing problem, while retrieving field data from JD Edwards to SQL (SSRS Reporting), giving Error or Special unicode characters,
because, the returning data was a stream that needs to be converted into ASCII (ebcdic37String) using Cp037 Encoding.

public static String convertEBCDIC37ToUnicode(String ebcdic37String)
{
 String encoding = "Cp037";
 byte[] ebcdic;
 String converted = null;
 try
 {
  ebcdic = ebcdic37String.getBytes();
  converted = new String( ebcdic, encoding );
 }
 catch (Exception e)
 {
  //Handle it
 }
 return converted;
}

Few days before, I was having problem that after clicking on Export to pdf button / image, other controls of web part/user control stops working on the application page on WSS 3.0 environemnt that has RadGrid on it.

While the same thing was working on other asp.net application outside the sharepoint environment.

1st workaround (can be a solution)

The cause for this behavior is that there is a flag (named _spFormOnSubmitCalled) in SharePoint which prevents double form submition. This flag is set when the form is submitted and clear when the response is received.
However when exporting the response is redirected and the page is not updated, thus the flag is not cleared and page's postbacks are blocked.

In order to workaround this behavior you should manually clear the flag when exporting. This can be achieve, for example in export button's client click function similar to the following:

MyExportButton.OnClientClick = "_spFormOnSubmitCalled = false;"  

Above workaround will allow you to export multiple times, but all the other controls on the page were still not functional after the export.

2nd workaround (Not / Never recommended)

In your sharepoint master page, remove onsubmit attribute from your form tag

<form runat="server" onsubmit="return _spFormOnSubmitWrapper();"> 

and remove the onsubmit attribute.  This is what it looks like now:

<form runat="server"> 

3rd workaround (so far so good and implementable)

Add the following script to your webpart / custom control that need to have export and other controls functionals, rather then implementing the above workarounds
So here you go with the working solution.

<script type="text/javascript" language="javascript">

    //sharepoint postback to work after clicking on telerik export to pdf
    if (typeof (_spBodyOnLoadFunctionNames) != 'undefined' && _spBodyOnLoadFunctionNames != null) {
        _spBodyOnLoadFunctionNames.push("supressSubmitWraper");
    }

    function supressSubmitWraper() {
        _spSuppressFormOnSubmitWrapper = true;
    }
   
</script>

Hope this will helps.

Today I was getting following error while writing to Event Log on Windows 2008 Server (also applicable to windows 2003 server) using .NET

The resolution worked for me was appending (A;;0x3;;;AU) in CustomSD without quotes under HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Eventlog\EventLogName in windows registry where AU is referring to "Authenticated Users". Because in W2K3, the security of Application Event Log is controlled by CustomSD.
After appending the value would be similier to

O:BAG:SYD:(D;;0xf0007;;;AN)(D;;0xf0007;;;BG)(A;;0x f0007;;;SY)(A;;0x7;;;BA)(A;;0x7;;;SO)(A;;0x3;;;IU)(A;;0x3;;;SU)(A;;0x3;;;S-1-5-3)(A;;0x3;;;AU)


If CustomSD doesnt exists, then create a string named CustomSD and set its value to O:BAG:SYD:(A;;0x3;;;AU)

 P.S. Be careful by taking proper backup of registry before doing any change to it.