zc0000

Active Directory Configuration Issues ...

2011-05-09T06:50:00Z

1. Configure a "Active Directory Domain Controller" on server A

2. Set Server B's domain to the domain configured in server A , say, "sample.com"

In step 2 we may get some exceptions as :

The following error occurred when DNS was queried for the service location (SRV) resource record used to locate an Active Directory Domain Controller (AD DC) for domain "xxx.com":

The error was: "DNS name does not exist."

(error code 0x0000232B RCODE_NAME_ERROR)

The query was for the SRV record for _ldap._tcp.dc._msdcs.xxxx.com

Common causes of this error include the following:

- The DNS SRV records required to locate a AD DC for the domain are not registered in DNS. These records are registered with a DNS server automatically when a AD DC is added to a domain. They are updated by the AD DC at set intervals. This computer is configured to use DNS servers with the following IP addresses:

xx.xx.xx.xx

- One or more of the following zones do not include delegation to its child zone:

xxx.com

com

. (the root zone)
The following error occurred attempting to join the domain "bamv2":

An attempt to resolve the DNS name of a domain controller in the domain being joined has failed. Please verify this client is configured to reach a DNS server that can resolve DNS names in the target domain. For information about network troubleshooting, see Windows Help.

This is possibly caused by wrongly setting the DNS server IP on the client which is intented to join the target domain.

Open Network and Sharing Center -> Local Area Connection Properties Dialogbox -> IPV4 Properties dialog -> Use the folowing DNS IP Address -> Set "Preferred DNS Server" to the target AD server ip address

A client problem, not server's : A network-related or instance-specific error occurred while establishing a connection to SQL Server...

2011-04-30T17:59:00Z

I don't know, when and why, I cannot connect remote SQL server from my win7 & winserver2008 (64bit) machines. When trying to connect a server by typing IP ( xx.xx.xx.xx ) in the server name in "Management studio->Connect Server" dialog box, I always get:

A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) (Microsoft SQL Server, Error: 53)

or ( If typing "xx.xx.xx.xx,yyyy" - assigning port )

A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: TCP Provider, error: 0 - TCP Provider: ) (Microsoft SQL Server, Error: -1)

Well , after cautious checking I am sure it is not caused by wrong server configuration, since I even tested onnection from another XP3 32bit computer and it's OK, implying problem lies in my win7 client.

It's really very,very weird ------ no detailed information for the error even seeking event viewer. Eventually & luckily I approach to get around it : just connect local server by type IP format server name: "127.0.0.1" ------ it is like some internal mechanism that "IP" server is triggered ; once IP is triggered locally, it could be applied on remote connection. After connecting "127.0.0.1" I could get my remote server connected.

Does anyone know why thing goes as this ?

How to circumvent "Cannot obtain value of local or argument as it is not available at this instruction pointer, possibly because it has been optimized away

2011-02-26T09:28:00Z

Sometimes when debugging code we can't "watch" variable's value and only get this alerting message:

Cannot obtain value of local or argument as it is not available at this instruction pointer, possibly because it has been optimized away

As this has been discussed in How to disable optimizations when debugging Reference Source. According to his second suggesion, I just leave a checkbox blank:

Then rebuild the project. Then in your main project which references the "originally optimized" project , you could see the variables are accessible now.

Base class' constructor takes effect even not explicitly called.

2010-04-07T06:28:00Z

I almost have no impression at all on a heavily important c# grammar issue......

Originally I thought base class' constructor doesn't participate in any of derived class' constructional logic unless explicitly called for serving , just like :

 
public Manager(int initialdata) : base()
{
    //Add further instructions here. 
}

In this manner the default constructor is to be called undoubtedly. However in my bad conception I think code like this:

 
public Manager(int initialdata)
{
    //Add further instructions here. 
}

doesn't call the base class' default constructor because there is no explicit code ":base()" coming after main class name "Manager" so the base default constructor has no impact here.

However I am wrong. The two pieces above are semantically identical. Official tutorial tells me:

In a derived class, if a base-class constructor is not called explicitly using the base keyword, then the default constructor, if there is one, is called implicitly.

Here is official link stating this case:

Using Constructors (C# Programming Guide)

asp.net Auto-generated SQLEXPRESS database: Failed to generate a user instance of SQL Server ( troubleshooting 1 )

2010-04-04T20:03:00Z

If you adopt .net Login controls to handle user authentication tasks and simply rely on default connection settings which generates SQLEXPRESS-based database in APP_Data folder , especially under the windows 7 or windows server 2008 system, you are likely to suffer several exceptions caused by similar reasons. One is like:

Server Error in '/SamplesApp' Application.

Failed to generate a user instance of SQL Server due to failure in retrieving the user's local application data path. Please make sure the user has a local user profile on the computer. The connection will be closed.

To thoroughly I log some repro steps.

I create a new application pool "SamplesAppPool" to host "SamplesApp".

The "SamplesAppPool" 's identity is assigned using the win7/winserver 2008 r2-recommended feature: "ApplicationPoolIdentity" , leaving "Load User Profile" as false currenctly.

Such setting is meant to create a special account with the same name as target pool to run W3WP.exe. For better security issue we no longer resort to Network Service. This is an improved model induced into new generation of windows OS.

However if we use default asp.net connection string settings to initialize a build-in asp.net security database ( assuming SQLEXPRESS instance installed ) , which means the conn string is like :

data source=.\SQLEXPRESS;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|aspnetdb.mdf;User Instance=true

'"User Instance=true" means that SQLEXPRESS service needs a User Profile envrionment to perform some initialization works. Since the aspnet worker process is run in "SamplesAppPool" account, there should be a special user profile folder caring this account. However , since we previously set "Not load user profile", system doesn't at all create such a profile , thus no corresponding user profile folder created:

From Control Panel\System and Security\System\Advanced system settings panel we can get user profiles information

As you can see , the required "SamplesAppPool" profile is not maintained here.

Accordingly , "SamplesAppPool" profile folder does not exist in Users folder:

To get around the exception , "Load User Profile" needs setting as "true"

Once above settings changed , such profile is created in system immediately:

So far , the SQLEXPRESS-related information has not been established in the profile folder yet. We need trigger something to make account-specified sqlexpress folder constructed automatically. That is : do what I mentioned at the top. If you simply click "create user" button in a CreateUserWizard control without any custom connection settings in web.config , you may find App_Data/aspnetdb.mdf is successfully created. In addition , exploring "SamplesAppPool" profile folder will supply such a view:

To change application pool identity to build-in account such as "Network Service" without taking care of "Local User Profile"settings can solve the issue as well , because these build-in account auto-position to current logon user profile folder as is ensured by default and erect SQLExpress folder ( eg. if I logon as "zc0000" the folder is located at : C:\Users\zc0000\AppData\Local\Microsoft\Microsoft SQL Server Data\SQLEXPRESS ). Nevertheless, this is no longer suggestive in new generation of windows OS ( window 7 , windows server 2008 r2 or latter ) . I think since Network Service has undertaken more and more tasks in the whole system, Microsoft designs such a new mechanism to help the powerful giant out of heavy load thus to have asp.net applications be more concentrative and secure.

Official knowledge base link concerning this issue:

Problems with SQL Server Express user instancing and ASP.net Web Application Projects

SQL SERVER 2008 Database Diagram: "Saving changes is not permitted"

2010-04-04T18:59:00Z

When making some datatable changes in db diagram environment, a popup window might show up with this message:

Saving changes is not permitted. The changes that you have made require the following tables to be dropped and re-created. You have either made changes to a table that can't be re-created or enabled the option Prevent saving changes that require the table to be re-created./p>

meanwhile saving progress stops.

It is because that SSMS by default prevents some operations that requires target tables to be recreated. To go over this block, the highlighted item in Options window needs unchecking.

For more details refer the official knowledge base link:

Error message when you try to save a table in SQL Server 2008: "Saving changes is not permitted"

Database operations through SQL: Database Restore ...

2010-03-29T13:50:00Z

If using sql to perform a database restoring , care the sql-codes very well. Any trivial mistake may prevent a successful execution. Cases are listed here based on simple experiments.

with operation: MOVE 'logical_file_name_in_backup' TO 'operating_system_file_name'

If logical file name not correctly set , following error is obtained:

Logical file 'FILE_NAME' is not part of database 'DATABASE_NAME'. Use RESTORE FILELISTONLY to list the logical file names.

RESTORE DATABASE is terminating abnormally.

To be continue...

MyLittleAdmin: Could not load file or assembly 'mlt_ver' or one of its dependencies. An attempt was made to load a program with an incorrect format.

2010-02-27T17:49:00Z

When first running mylittleadmin web application I get exception as titled. It is because of the application is running on 64-bit asp.net process currently but is designed to work on top of 32-bit asp.net mechanism only.

Based on different IIS suites ( IIS6 & IIS7 ) there are 2 workarounds to solve the problem separately:

If IIS6 are just running 64-bit asp.net now, you need manually type some commands to enable 32-bit asp.net version:

Enable 32bit asp.net on 64bit platform by running adsutil.vbs set w3svc/AppPools/Enable32bitAppOnWin64 1 in \\%homedrive%:\Inetpub\Adminscripts
Reset IIS to have the switch-on take effect by typing "iisreset".
Above 2 steps just allow possibility of running 32bit asp.net on IIS; essentially, the 32bit asp.net framework is acquired to be registered to IIS by executing 'aspnet_regiis.exe -i' in the context of 32bit .net framework, thus to have itself be "truely" up.( 32bit .net framework folder is C:\WINDOWS\Microsoft.NET\Framework\vxx.xx while 64bit framework folder is C:\WINDOWS\Microsoft.NET\Framework64\vxx.xx)
"Allow" 'ASP.NET v2.0.50727 (32-bit)' in Web Service Extensions.

If otherwise IIS7 serves application, things are drastically simplified: select the target applicatin pool, set "enable 32bit application" to "true" in "Advanced Settings" panel. Then application runs as expected.

Refer to here.

Solution to the alert "The object identifier does not present a valid object" when trying to debug IIS-supplied applications through VS

2009-08-31T10:12:00Z

Met the error and felt wield ...

Then I found a great article to explain the reason and point to the key of truth.

http://blogs.iis.net/brian-murphy-booth/archive/2008/06/03/visual-studio-2008-unable-to-debug-asp-net-app-on-iis-7-0.aspx

---------------------------------------------------------------------------------------------------------------

When attempting to "run" an ASP.NET project on IIS 7.0 using Visual Studio 2008 the following error is displayed:

RESOLUTION:

Make sure that "Windows Authentication" is enabled in IIS on the applicable web application (web site or folder).

NOTES:

That was a little frustrating for me at first. No hits anywhere in our knowledge base or on Live. I figured I would ignore this and come back to it later but after about a week I finally decided this isn't something I wanted to deal with constantly. I started to troubleshoot it versus waiting to find somebody else's solution. One of the first things Visual Studio does when trying to debug an ASP.NET application is make a DEBUG request (versus a GET or POST) to IIS. If all goes well for the DEBUG request, VS automatically attaches as a debugger to the ASP.NET worker process (w3wp.exe in this case) and to IEXPLORE.exe. So into the IIS logs I went to see the result of that DEBUG request. Here was the entry for my failed debug attempt:

#Software: Microsoft Internet Information Services 7.0
#Version: 1.0
#Date: 2008-06-03 12:11:16
#Fields: date time s-ip cs-method cs-uri-stem cs-uri-query s-port cs-username c-ip cs(User-Agent) cs(Cookie) sc-status sc-substatus sc-win32-status time-taken
2008-06-03 12:11:16 ::1 DEBUG /WebApp/Default.aspx - 80 - ::1 - - 401 0 0 157

You may notice that this is a 401.0. Normally when a "browser" (VS2008 in this case) first makes a request it is always anonymous. Then after seeing a 401, it will follow up the first request with a second request that includes credentials. In the IIS logs we'd expect to see a 401.2 (unauthorized due to sever configuration - i.e. I'm not accepting anonynous), then if using NTLM we'd see a 401.1 (NTLM challenge - i.e. you have only sent me half the credentials for that NTLM handshake) then finally a success status such as 200 (OK), 302 (Moved/Redirect), or 304 (Not Modified). Or if using Basic authentication or Kerberos there would be the 401.2 then the success status for the next log entry since those methods don't have a handshake. In my case here there was only a single 401 with no follow up attempt. Hmm... Why no follow up request with credentials? Next stop - IIS manager.

After highlighting my "WebApp" folder and double-clicking "Authentication" (shown above) in the IIS manager I saw that only Anonymous was enabled. Oh right... IIS 7.0 is secure by default. VS was making it's anonymous request and since IIS returned no "WWW-Authentication" headers specifying which auth method it is accepting, VS quit there. IIS 7.0 has only anonymous enabled by default and administrators have to consciously open up their server by enabling additional authentication types. After enabling "Windows Authentication" as well leaving "Anonymous" enabled, debugging worked fine. Thanks for the great error!!

Alert Cannot set a credential for principal 'sa' .... when trying to modify 'sa' properties through sql management studio 2008..

2009-08-08T13:35:00Z

http://support.microsoft.com/kb/956177

You receive an exception in SQL Server 2008 when you try to modify the properties of the SQL Server Administrator account by using SQL Server Management Studio

SYMPTOMS
Consider the following scenario. You use the Microsoft SQL Server 2008 tools to...

Consider the following scenario. You use the Microsoft SQL Server 2008 tools to connect to a server that is running Microsoft SQL Server 2005. You open the properties dialog box for the SQL Server Administrator account, and then you perform an "sa" login by using the SQL Server Management Studio tools. You modify the properties for the "sa" login, and then you click OK. In this scenario, you receive the following error message:

TITLE: Microsoft SQL Server Management Studio
------------------------------
Alter failed for Login 'sa'. (Microsoft.SqlServer.Smo)
------------------------------
ADDITIONAL INFORMATION: An exception occurred while executing a Transact-SQL statement or batch. (Microsoft.SqlServer.ConnectionInfo)
------------------------------
Cannot set a credential for principal 'sa'. (Microsoft SQL Server, Error: 15535)
------------------------------

Back to the top

CAUSE
This problem occurs if the Map To Credential check box is not selected on the Ge...

This problem occurs if the Map To Credential check box is not selected on the General tab of the Login Properties - sa dialog box. If this check box is not selected, SQL Server 2008 will try to drop any credential that is mapped to your login credentials. Because your credentials cannot be set to the "sa" login, you receive the exception error message that is mentioned in the "Symptoms" section when you click OK to close the dialog box.

Back to the top

RESOLUTION
To resolve this issue, make sure that you select the Map To Credential check box...

To resolve this issue, make sure that you select the Map To Credential check box on the General tab of the Login Properties - sa dialog box before you change the "sa" login properties and then click OK to close the dialog box.

IIS7 FTP settings Instruction .....

2009-08-08T09:16:00Z

IIS7 FTP settings

http://learn.iis.net/page.aspx/320/using-ftp-virtual-host-names/

FTP 绑定之时，如果需要使用域名访问，则不但要绑定 FTP 域名 ftp.domain.com （一个绑定记录），还必须要一个 unassigned 绑定，直接绑定IP ！

两条绑定记录都是必须的！

Solve an alert occuring when trying to save in ManagementStudio Table-design interface:Saving changes is not permitted

2009-07-19T12:31:00Z

Saving changes is not permitted. The changes that you have made require the following tables to be dropped and re-created.

ERROR:

“Saving changes is not permitted. The changes that you have made require the following tables to be dropped and re-created. You have either made changes to a table that can't be re-created or enabled the option Prevent saving changes that require the table to be re-created.”

This error happens because “Saving Changes is not permitted” when using SQL Server 2008 Management Studio to modify the structure of a table especially when SQL Server needs to drop and recreate a table to save the structural changes. It is always advised to make a structural change for a table using TSQL. However, it is a convenient option for database developers to use SQL Server Management Studio make such changes as the Prevent Saving Changes That Require Table Re-creation option is enabled by default in SQL Server 2008 Management Studio.

Disable “Prevent saving changes that require the table re-creation”

1. Open SQL Server 2008 Management Studio (SSMS). Click Tools menu and then click on Options... as shown in the snippet below.

2. In the navigation pane of the Options window, expand Designers node and select Table and Database Designers option as shown in the below snippet. Under Table Options you need to uncheck “Prevent saving changes that require the table re-creation” option and click OK to save changes.

This option when enabled prevents users from making structural changes to table using SQL Server Management Studio especially when SQL Server needs to recreate the table to save changes. By default, this option is checked and you need to uncheck this option to allow users to make any structural change through SSMS that require table recreation.

A table needs to be recreated whenever any of the below changes are made to the table structure.

· Insert a new column in the middle of the table.

· Add a new column in the table.

· Change the Allow Nulls setting of a column.

· Modify the identity property of a column.

· Reorder the columns within a table.

· Modify the datatype of a column.

Once you have disabled “Prevent saving changes that require the table re-creation” option you can go ahead and save the changes to the Employee Table. This will create a Validation Warning dialog box as shown in the below snippet. The warning message will be “One or more existing columns have ANSI_PADDING 'off' and will be re-created with ANSI_PADDING 'on'”. Click “Yes” to save the changes.

Risks of Turing Off "Prevent Saving Changes that Require Table Re-creation" in SSMS

If you turn off this feature then you can avoid table recreation. However, if you have the Change Tracking feature of SQL Server 2008 enabled to track the table changes then the change tracking information will be lost completely whenever table is recreated. So, it is always advised to use this feature very carefully especially in a production environment.

Refer to http://www.sql-server-performance.com/faq/saving_changes_not_permitted_p1.aspx

A CALLBACK function is always triggered at LAST in a code route !!

2009-07-08T20:35:00Z

A segment of javascript code :

 function getValue() {
          var rel = null;
          CustomService.GetValueFromServer(
          function(result) {
              rel = result;
          }
          );

          return rel;
      }

    var myValue = getValue();

CustomService is a "ScriptService" attributed c# webService class with a functional method "GetValueFromServer" supplying certain string value :

[WebService(Namespace = "http://tempuri.org/"),
WebServiceBinding(ConformsTo=WsiProfiles.BasicProfile1_1),
ScriptService]
public class CustomService : WebService
{
    [WebMethod]
    public string GetValueFromServer()
    {
        return "Yes I have got it.";
    }
}

Then , guess what will happen to "myValue" ? Will it be "Yes I have got it" ?? No , its value will be null after assignation.

The reason is revealed in article subject. CALLBACK is always occuring at the very end.

If you are not quit familar with client invocation of webservice please reference the official link :

Calling Web Services from Client Script in ASP.NET AJAX

Now let me explain the short route.

"var myValue = getValue()" invokes getValue() method , where following steps execute subsequently :

"rel" is initialized with null
CustomService.GetValueFromServer() is called. But no js code excutes at this time at client! Note the function() is just a CALLBACK on a successful condition! As subject reveals , it will not be ruded in at this time , meaning "result" is not passed to rel.
"rel" , a variable not passed with any value and staying null , is returned.
Consequently , "myValue" only get a null value.
Eventually , the "onSucceed" callback function is fired ! Whatever happens in it , it loses the chance to provide client an expected value.

Exception: The mapping of interface member IMetaEntity.Url is not supported

2009-06-25T18:06:00Z

Though "Url" is an "LinqToSql" generated property and strictly map to a database field the exeption still yields when where clause is written as

from item in db.GetTable<T>

where item.Url = "http://xxxxxx"

select item;

Solution: such writting should be modified as : item.Url.Equals( "http://xxxxxx" )

Then the exception is avoided.

Why ? I do not know. Someone points out that it is Linq Team's mistake ...

GallaryServerPro:Could not load file or assembly 'ComponentArt.Web.UI' or one of its dependencies

2009-05-29T16:16:00Z

It is because the block action conducted by Mcafee !

Access Protection -> Common Maximum Protecttion -> Prevent creation of new excutable files in the Windows Folder

Unblock it ! Then everything is OK.

For just a web application I need make some risk ...