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

Get-SPSite | where {$_.url -like "http://a *"}

Get-SPFarm | Format-List Id, BuildVersion, Servers, Solutions

Add-PSSnapin Microsoft.SharePoint.Powershell

===========

ExecuteHelloWorldScript from batchfile

powershell -Command "& {.\Hello.ps1}" -NoExit
pause

powershell -Command "& {Set-ExecutionPolicy bypass}" -NoExit

===========

CreateContosoSite

if($args) {
  $SiteName = $args[0]
  $SiteUrl = "http://a:3811/sites/ " + $SiteName
  Write-Host "Begin creating Contoso site at" $SiteUrl
  Write-Host
  $NewSite = New-SPSite -URL $SiteUrl -OwnerAlias Administrator -Template STS#1 -Name $SiteName
  $RootWeb = $NewSite.RootWeb
  $RootWeb.Title = "Contoso Site: " + $SiteName
  $RootWeb.Update()
  Write-Host "New Contoso site successfully created"
  Write-Host "-------------------------------------"
  Write-Host "Title:" $RootWeb.Title -foregroundcolor Yellow
  Write-Host "URL:" $RootWeb.Url -foregroundcolor Yellow
  Write-Host "ID:" $RootWeb.Id.ToString() -foregroundcolor Yellow
}
Else {
  Write-Host "ERROR: You must supply Name as parameter when calling CreateContosoSite.ps1"
}

===========

GetSharePointDlls

$path = "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14"

Get-ChildItem $path -recurse |
  Where-Object {$_.name -like "*SharePoint*.dll"} |
  Sort-Object -Property Name -unique |
  Format-Table Name

===========

GetSharePointPublishingFeatures

Get-SPFeature -Limit ALL |
  Where-Object {$_.DisplayName -like "*Publishing*"} |
  Sort-Object -Property Scope
  Format-Table DisplayName, Id, Scope

===========

.\GetSharePointPublishingFeatures.ps1
Get-SPFarm | Format-List
Get-SPSite | where {$_.url -like "http://a *"}
.\CreateContosoSite.ps1 lab01test

===========

Query to find all the Tables and Index with number of days statistics being old. Then run Update Statistics command to update statictics for optimized query plan.

SELECT
OBJECT_NAME(A.object_id) AS Object_Name,
A.name AS index_name,
STATS_DATE(A.OBJECT_ID, index_id) AS StatsUpdated ,
DATEDIFF(d,STATS_DATE(A.OBJECT_ID, index_id),
getdate()) DaysOld
FROM sys.indexes A
INNER JOIN sys.tables B ON A.object_id = B.object_id
WHERE A.name IS NOT NULL
ORDER BY DATEDIFF(d,STATS_DATE(A.OBJECT_ID, index_id),getdate()) DESC

To view the detailed error information for generic error against 500 Internal Server Error

By default, Windows hosting servers display a generic error when any .NET application generates an exception. They display a generic error because the detailed error messages allow a malicious user to obtain sensitive information.

To troubleshoot the error, you can modify your web.config file and specify that a custom error message displays. A custom error message helps you to locate the specific code that is causing the issue.

CAUTION: The code samples we provide below do not constitute a complete web.config file. Do not replace your existing web.config file with the code we provide. Before changing your web.config file, we recommend creating a backup.

Displaying Custom Error Messages / Enabling Detailed Errors on IIS 6

<configuration>
    <system.webServer>
        <httpErrors errorMode="Detailed" />
        <asp scriptErrorSentToBrowser="true"/>
    </system.webServer>
    <system.web>
        <customErrors mode="Off"/>
        <compilation debug="true"/>
    </system.web>
</configuration>

=========================

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

SPWeb has two sharepoint cross-site group collection, SPWeb.Groups and SPWeb.SiteGroups.

SPWeb.Groups returns collection of cross-site groups which has some permission on the site. So if you add group from a site without any permission on the site, then this group wont appear in SPWeb.Groups collection, but it will appear in SPWeb.SiteGroups collection.

You can not use SPWeb.Groups.Add method to add new cross-site group, you need to use SPWeb.SiteGroup.Add method for this purpose.

In addition to this SPWeb has a property AssociatedOwnerGroup, which will return the required SPGroup. You can iterate the SPGroup users to get the list of all owners of the site.

 foreach (SPUser user in web.AssociatedOwnerGroup.Users)
 {
      // .. list all the users                        
 }

Finding and adding group

SPGroup  group = GetSiteGroup(web, "groupName");
if (null == group)
{
 web.SiteGroups.Add("groupName", web.AssociatedOwnerGroup, null, "Test Group description");
}

private static SPGroup GetSiteGroup(SPWeb web, string name)
{
    foreach (SPGroup group in web.SiteGroups)
    {
 if (group.Name.ToLower() == name.ToLower())
 {
     return group;
 }
    }
 return null;
}

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;
}