asithangae

MVC.Unity Framework - Are you missing a type mapping?

2013-01-20T20:22:00.001+05:30

When we implement the Unity Framework for the first time, we may get this error.

The current type, System.Web.Mvc.IControllerFactory, is an interface and cannot be constructed. Are you missing a type mapping?

When we implement the IDependencyResolver of Unity Framework, GetService method will resolve the requested service type and return the actual object. The moment we write our custom resolver by implementing the Unity Framework, MVC framework things that we are going to take care of resolving all the types.

Type resolving happens in the following order .

- IControllerFactory
- IControllerActivator
- HomeController

We resolve for the objects which we create in our application and not for the default objects of MVC. so we need to return null for the objects for which we did not register. That way we can avoid the error because the MVC by default have resolvers. When we return null in our custom resolver, it considers the default resolver and proceed with implementation.

public object GetService(Type serviceType)
{
return this._container.IsRegistered(serviceType) ? _container.Resolve(serviceType) : null;
}

Please refer this link to get more insight on this.

Unable to create a SQL Job in my local machine

2012-08-29T19:20:00.000+05:30

Error while creating a SQL Job in local SQL Server DB Instance.

I got below error when I try to create a SQL job in SQL Server 2005 Instance.

Unable to cast object of type 'Microsoft.SqlServer.Management.Smo.SimpleObjectKey' to type 'Microsoft.SqlServer.Management.Smo.Agent.JobObjectKey'.

When i check for a fix, i see lot of users asking to uninstall and install the SSIS, but that does not resolve this issue.

This happens on 2 reasons.

1. If we don't have latest service pack installed (SP3) in your machine.
2. If we try to run the job with SQL Agent service account and that does have privilege to execute a SSIS package.

you can check the below code project link, which helps to create a proxy account for you domain account, using that you can run the job.

Hope this helps.

CodeProject

VS or BITS Toolbox items missing

2012-08-25T00:22:00.000+05:30

When i open my Business Intelligence Studio to update my SSIS package, i noticed that all my toolbox items were missing. When i try to add that using choose components, I am able to add all the items which are missing. But the grouping of items as sources, destination and so on are not happening with that manual addition of items.

I Google and many answers mentioned to import tool box settings, but that does not work. Also some people asked to re-install or repair, that does not works.

One of the solution was to delete the files in the cache folder, that is the only solution which really helped.

Delete the files which starts with toolbox or with extension tdb from the location:

For Windows 7 - C:\Users\bmanohar\AppData\Local\Microsoft\VisualStudio\8.0

Others OS - C:\Documents and Settings \bmanohar\Local settings Application Data\Microsoft\VisualStudio\8.0

I am trying to fix the issue for VS2005, so cleaning the files from location 8.0. for 2008 check 9.0 and 2010 check 10.0

deleting the files does not harm your studio any way, because it as cache file. It will create a fresh copy when you open the studio next time in the same location.

Ignore CA1405: COM visible type base types should be COM visible

2012-07-19T19:16:00.001+05:30

CA1405: COM visible type base types should be COM visible : A COM-visible type derives from a type that is not COM-visible.
ComVisible(true) is on by default through the compiler. Ignore this warning.
If we really need ComVisible(true), then we need to set that in assembly properties. We can remove this from the Microsoft Minimum Ruleset and customize it.

Copy Paste Problem between local and Remote machines

2012-03-07T12:14:00.001+05:30

In the Remote machine. open the task manager and in processes tab, select rdpclip.exe and end process. try disconnect and connect, it will start working again. This solution works for Win 2008 R2 OS.

Assigning values to SQL variable using Select Query

2012-01-28T09:48:00.001+05:30

Assigning a value to SQL variable:

Declare @date Datetime

set @date = getdate()

We can achieve the same using simple select statement:

select @date = getdate()

If we try to do the same from a result of query, then it will be

select @date = DateCreated from SomeTable where PrimaryKey = SomeValue

We are sure that this query will return only one record, so this statement is valid and always returns expected result. In a scenario, where the result is more than one then which value will be assigned to that variable. Will it be first record or last record or anything in between?

declare @empid char(8)

select top 10 @empid = empid from Empmaster where DeptID = 'A' order by empid

select top 10 * from Empmaster where DeptID = 'A' order by empid

select @empid

It will always get assigned to the last result data. So to be on the safe side we need to put the order by clause and use the appropriate order as ascending or desending considering the fact it always pull the last record. Otherwise we need to use the “Top 1” so it always use the value of first record in the result with proper sorting.

Handling Ajax Asynchronous Post Back Error

2012-01-23T22:51:00.000+05:30

I read this solution in one of the article, just want to share the same.

1. We can handle ajax errors from client side by adding a custom handler to end_request event of PageRequestManager object.
2. We can handle this by binding a error handler method to property OnAsyncPostBackError of Script manager object.

Client side handling:
<script type="text/javascript" language="javascript">
Sys.WebForms.PageRequestManager.getInstance().add_endRequest(EndRequestHandler);

function EndRequestHandler(sender, args) {
  if (args.get_error() != undefined) {
    var errorMessage;
    if (args.get_response().get_statusCode() == '200') {
      errorMessage = args.get_error().message;
    }
    else {                
      // Error occurred somewhere other than the server page.
      errorMessage = 'An unspecified error occurred. ';                                }
    args.set_errorHandled(true);                
  }
}
</script>

Server side handling:

<asp:ScriptManager ID="ScriptManager1" runat="server" OnAsyncPostBackError="ScriptManager1_AsyncPostBackError"></asp:ScriptManager>

protected void ScriptManager1_AsyncPostBackError(object sender, AsyncPostBackErrorEventArgs e){
  if (e.Exception.Data["ExtraInfo"] != null){
    ScriptManager1.AsyncPostBackErrorMessage = e.Exception.Message + e.Exception.Data["ExtraInfo"].ToString();
  }
  else{
    ScriptManager1.AsyncPostBackErrorMessage = "An unspecified error occurred."
  }
}

Invoking mouse events through JavaScript

2011-11-29T21:45:00.001+05:30

Handling Mouse Events through Java script

In some scenarios, we may need to invoke a button click through script. We can write element.click(), but that will not work in all the browsers. We may need to do this in another way, please check the below code snippet.

function invokeSaveClick(saveElementId) {
var e = document.createEvent('MouseEvents');
e.initEvent('click', true, true);
document.getElementById(saveElementId).dispatchEvent(e);
}

Request.ApplicationPath is not working in some cases

2011-11-29T00:44:00.001+05:30

Request.ApplicationPath will work only IE. When we want to support different browsers like Chrome, Safari and Firefox, we should use the below property to get the correct relative URL.

this.Request.Url.GetLeftPart(UriPartial.Authority)

Example:

If we use Request.ApplicationPath

window.open('" + Request.ApplicationPath + "/abc/testpage.aspx?x=1"','test page', 'toolbar=no,directories=no,status=no,menubar=no,scrollbars=yes,resizable=yes ,modal=yes'); }", true);

It will be rendered as http://abc/testpage.aspx?x=1

If we use Request.Url.GetLeftPart(UriPartial.Authority), then it will be rendered as
http://ServerName/abc/testpage.aspx?x=1

View State Issues in ASP.Net

2011-10-03T14:42:00.001+05:30

We are getting some of the view state related errors in our application.

Invalid view state.
Unable to read beyond the end of the stream.
The serialized data is invalid.
The client disconnected.

The reason for this errors are one of the one mentioned below:

1. The application may be deployed across farms and the encryption/Decryption keys may vary in the servers, so it may throw errors intermittently.
2. The View state may be very large or bloated, so it may reduce the application performance and may cause issue while serialization or deserialization of View state.

Possible solution for this issue are,

1. We can set the encryption validation key at the application level in the web.config file. It looks like the one mentioned below.

<machinekey decryption="AES" decryptionkey="4C05D6B56FA0A057F519884A1C3B5B42B14491ED56CB44F942EE3A0CA2848D29" validation="SHA1" validationkey="ABFD56FE84823AE69E9A613CE998803F4246FE0D96DC48E7BB9E715B0A57352CEFB35264EFB8C0F710E154F42B7460B7CDE9A99F225DA796DEE5E5F94F8F7188"></machinekey>

We can generate keys online from this location. http://aspnetresources.com/tools/machineKey

<pages enableviewstatemac="true">

We can also set the enableViewStateMac to true, but we have some issues when we implement the both these fixes. It may throw user a run time error or compiler warning. It will not allow you to debug sometimes.

3. Other simple solution to overcome this issue is to break the view state in to multiple chunks so that we can avoid the serialization error. This can be achieved by setting a simple property in the pages element of config file.

<pages maxpagestatefieldlength="20">

4. We can also compress and decompress the view state using a simple logic and have that code in the Base Page of the application. We can use compression at the page level by setting a property. Please check the code project link for a detailed explanation on this.

http://www.codeproject.com/KB/viewstate/ViewStateCompression.aspx

These are some of the things I found during my search, i put all the points in one stop for your reference. It worked for me. Hope the same for you all.

Blind SQL Injection

2011-09-26T19:04:00.000+05:30

SQL Injection can be avoided using HTML encoding. Please find the list of characters which needs to be handled which getting user inputs especially in multi-line text boxes.

[1] | (pipe sign)

[2] & (ampersand sign)

[3] ; (semicolon sign)

[4] $ (dollar sign)

[5] % (percent sign)

[6] @ (at sign)

[7] ' (single apostrophe)

[8] " (quotation mark)

[9] \' (backslash-escaped apostrophe)

[10] \" (backslash-escaped quotation mark)

[11] <> (triangular parenthesis)

[12] () (parenthesis)

[13] + (plus sign)

[14] CR (Carriage return, ASCII 0x0d)

[15] LF (Line feed, ASCII 0x0a)

[16] , (comma sign)

[17] \ (backslash)

Their is always a chance of manupulating the SQL script as part of form inputs and also end user can prepare a request dynamically and hit the target url's. If we use the HTML encode and decode this can be avoided.

Example:

While getting the input values from the form and before processing that.

string data = HTTPUtility.HTMLEncode(Textbox1.Text)

While rendering the data to UI

Textbox1.Text = HTTPUtility.HTMLDecode(data)

This is simple and one of the best practice to avoid SQL injection.

Cross Site Scripting : Validating Query string parameters string

2011-04-12T15:39:00.000+05:30

1. We need to validate the request by setting the ValidateRequest="true" on the @ Pages element.

2. We need to take care while using query string parameter. We need to cast the query string value to the respective data type to avoid this. Please check the below code snippet to avoid this. This will help us to check whether user end is manipulating something in the URL, if so then we cannot create a new GUID the catch block will be executed and generic error message will display. the same logic can be applied for any data type.

try
{
string Key = Request.QueryString["e"];
Guid ErrorGUID = new Guid(Key);
lblError.Text = string.Format("Please provide the following error code {0}.", ErrorGUID.ToString();
}
catch ()
{
//handle exceptions accordingy
}

SSIS Error code DTS_E_OLEDBError 0X8004005 ...

2011-03-11T15:16:00.000+05:30

SSIS Error Code DTS_E_OLEDBERROR. An OLE DB error has occurred.
sometimes we get as "Login failed for user" or "User might not have permission to do the activity".

I was getting this error for quite sometime when I execute the package using "Execute Package utility" I tried looking this msdn site for , but that does not help. Even though i changed the settings and try to execute it is prompting the same error.

Reason: At last i got the solution from this msdn blog (which also contains solution for different kinds of SSIS errors). While setting the DB connection, I check the save password check box to avoid entering multiple times. That is reason for it. Normally if we have to set the password permanently for the connection then we are suppose to set the password for package also. And also the package encryption level must be set to "EncryptSensitiveWithPassword" or "EncryptAllWithPassword". This both go in pair. If you set the encryption level and not setting the package password it will throw an error.

Solution:
1. While setting the connection details, we should not check the Save Password option and package encryption can be default. As a best practice, we can set the package configurations through config file.

Reference for package configurations in msdn site

Prerequisite:
1. Make sure you have the latest version of BIDS.
2. Update the SQL server with all available service packs.
3. While setting the connection string using config file, please make sure you are setting the connection provider also.

Migration from VS 2005 to VS 2008

2011-03-10T16:59:00.001+05:30

I recently got a opportunity to migrate a VS2005 project to VS2008. I was reading all the pros and cons of migration from the different sites. The simple thing to migrate the solution is open the 2005 solution from the VS 2008 IDE, it opens a wizard and take you through each step and convert the whole project. After migration it creates a Migration report which tell the status of migration. 99% of the project gets migrated in one click. Some of the solution will have a problem. If you get a chance to compare the sln file before and after migration the only change you can find is mentioned below:

VS2005 sln file: Microsoft Visual Studio Solution File, Format Version 9.00
VS2008 sln file: Microsoft Visual Studio Solution File, Format Version 10.00

The project files (*.vbproj or *.csproj) will not be affected or modified during the migration.

One more way to do this is create a Blank solution in VS2008 and start adding vs2005 projects to it. If we have multiple projects, then it will be little tedious to add each and every project.

We have a constraint here. If you solution has SSRS or SSIS projects associated to that then it will not get migrated on its own. We need to migrate it separately. While doing this we should make sure the SQL versions is also upgrated to SQL Server 2008. It is simple in development machine, but while deploying if the environment does not support then we will be in trouble. But for Window and Web projects, we will not find any problem until we change the framework. VS2008 supports multi-targeting, I mean it supports to compile and run your project in different framework starting from Net Framework 2.0.

One more funniest thing is we can have two sln files for same project to work in two different VS versions. This will not affect the project until you do not change the target framework. This is not a best practice, but helps in critical situations.

I referred the below link to know more information before migrating the project. This is really worth reading even for knowledge sake.

Business Intelligence Development Studio 2005 (BIDS)

2011-03-10T16:22:00.000+05:30

I recently want to update visual studio 2005 with service pack. The moment i installed in my machine, my studio started behaving very funny. IDE is having repeated menu items with repeated sub menu. I tried repair the studio with reinstalling the service pack and the problem is still more worse. Menus got doubled than before. I tried setting the IDE using Import and Export setting and that does not help. All I need is BIDS and not full version of VS2005 as my projects are migrated to higher versions. So I uninstall the VS2005 from my machine. I uninstall Visual Studio Premier Partner Edition also (by mistake), Please do not uninstall that as it is required for BIDS.

I have SQL Server 2005 database services installed already in my machine, and I downloaded the latest version of service pack for Microsoft SQL Server 2005 (Service Pack 4 RTM) and installed in my machine. During the installation wizard there is a option to select the tool which you want to upgrade, select all and proceed.

Installation went well with one fix failed, and it opened the provisioning tool to set the access for my SQL server database engine. Once the installation is done, IDE started configuring on its own and it ready. I got this information in one of the site mentioned below. But still I want to post the full history to understand the history behind this.

Info I found in that site:

You should make sure that Visual Studio is still installed. If you didn’t previously have VS installed, the BI Dev Studio installation will install a VS shell called Visual Studio Premier Partner Edition. Look in Add or Remove Programs for an entry like this. If you don’t find any entry for Visual Studio go to the location for SQL Server setup and run .\Tools\Setup\vs_setup.exe. This will install the VS Shell. After this is installed repair the BI Studio installation by running the following from the command line from the .\Tools directory: start /wait setup.exe /qb REINSTALL=SQL_WarehouseDevWorkbench REINSTALLMODE=OMUS

SSRS sub report not visible while rendering

2011-02-17T16:12:00.001+05:30

We need to verify the Hidden property in the visibility section and make sure it is said to false (hidden=false). Remove the expression and try hardcoded values like true or false. Make sure all the parameters defined in the sub report are properly associated in the main report. One of the reasons is if the sub report is having dataset associated to it and the dataset is not returning a single record will be a problem. Otherwise the record may contains all null values.

SQL SERVER 2005 Uninstalation issue ( Error code : 2147024893)

2010-06-05T22:33:00.000+05:30

Error : The setup failed to read IIsMimeMap table. The error code is -2147024893.

Description : we get this error when we try to uninstall the reporting services individually or SQL server 2005 as a whole package. the reason for this selecting the mixed mode for authentication while installation. even the microsoft does not have the solution for this.

Workaround for this is ...
1. Uninstall the IIS
2. Uninstall the SQL server 2005 or reporting services.

Happy Coding :)

ADGroup Verification in ASP.NET Web Applications

2009-06-19T12:07:00.000+05:30

Normally in Enterprise level , users will be provided access at the ADGroup level for the application that are hosted at the intranet and internet. The web application will contains the access related code. There are two to check this access at ADGroup.
1. LDAP QUERY
2. Net inbuilt method

The first one LDAP approach is more time consumable. Also to add more value, we will be using a service account to pull the Active Directory information. This is risk, we are pulling firm sensitive data from the Active Directory. Moreover to check a single ADGroup, we are pulling all the existing and verifying it via loop. This is a bad practice. And causes Performance issues.

The Dotnet inbuilt function IsInRole is simplest way to achieve this. we need to know the domain name where the ADGroup is in place. The syntax for this goes like this.

bool IsHavingAccess = HttpContext.Current.User.Identity.IsInRole(domain\Adgroup);

This will help us to just verify the access security and provide the result. So by using this method, we are nowhere pulling sensitive information and logic will be very fast. Hope this helps.

CodeProject

Dynamically assign a function to event in javascript

2009-06-07T17:44:00.000+05:30

In javascript, using code we can assign function to the events of the elements.

In general, we can assign the function name to the event name directly, Please see the below example.

var element = document.getElementById("testElement");
element.onclick = DynamicFunction;

function DynamicFunction()
{
 alert("sample function");
}

Consider a scenario where you have to assign a function with parameters. we cannot do in the below mentioned way. this will throw a script error.

var element = document.getElementById("testElement");
element.onclick = DynamicFunctionWithParameters(x,y);

function DynamicFunctionWithParameters(param1, param2)
{
 alert("sample function");
}

we have to go with a round about way to achieve the same, see the below example.

var element = document.getElementById("testElement");
element.onclick = function(x,y){DynamicFunctionWithParameters(x,y);};

function DynamicFunctionWithParameters(param1, param2)
{
 alert("sample function");
}

I think you know, we can even directly write the function instead writing it separately and assigning it to the event later. the below example explains this. while mentioning this way we cannot have the function name, and also the same function cannot not be reused.

var element = document.getElementById("testElement");
element.onclick = function(param1, param2)
{
 alert("sample function");
};

HttpContext is Null

2009-04-13T18:03:00.001+05:30

In ASP.Net application, HttpContext type will be instantiated for current thread and it loads all the context values related to the Request sent to the server. While we use the Asynchronous concept in the ASP.Net application, the HTTPContext will not have a reference or values in the asynchronous thread. Apart from the normal Page execution thread, new threads will be created for every Async task we are using, So while referring those Context objects Care should be taken. Otherwise the application will throw error.
HttpContext.Current object will be null, when we are using Asynchronous task [PageAsyncTask].
To avoid this or overcome this, capture the needed values from the base thread and share it with a static class to the other threads. This capturing of values should happen before the invoking of Async Calls.

Mime Content Types for office 2007 documents

2008-05-08T17:30:00.000+05:30

The Content Type of the office 2007 files are different from the normal office documents. the files are strored and maintained internally as xml formats. While uploading these documents they are uploaded in octet stream[binary stream].
For more details check this link. openxmldeveloper.org

The Content Types of the office 2007 files is listed below.

File Extension	Content Type
docm	application/vnd.ms-word.document.macroEnabled.12
docx	application/vnd.openxmlformats-officedocument.wordprocessingml.document
dotm	application/vnd.ms-word.template.macroEnabled.12
dotx	application/vnd.openxmlformats-officedocument.wordprocessingml.template
ppsm	application/vnd.ms-powerpoint.slideshow.macroEnabled.12
ppsx	application/vnd.openxmlformats-officedocument.presentationml.slideshow
pptm	application/vnd.ms-powerpoint.presentation.macroEnabled.12
pptx	application/vnd.openxmlformats-officedocument.presentationml.presentation
xlsb	application/vnd.ms-excel.sheet.binary.macroEnabled.12
xlsm	application/vnd.ms-excel.sheet.macroEnabled.12
xlsx	application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
xps	application/vnd.ms-xpsdocument

Manual verification of Validation Controls before getting submitted using Javascript

2008-05-07T13:37:00.001+05:30

The Validation controls plays a major role in validation client data before it is getting posted in to the server. This is done by placing the appropriate validation controls required. This takes care of data validation before posting on its own. Suppose this same task has to handle even when validation controls are present. Let us see this.
A JavaScript function displayed below will takes care of a similar task.

function VerifyValidators()
{
    //To verify the validators are passed in data validation.
    //This Page_ClientValidate() function will return true if all the validation are passed else it returns false.
    if (Page_ClientValidate() == true)
    { 
        form1.submit();
    }
}

The Page_ClientValidate() function will not be included in the page by default. To implement this function we need a minimum a single validation control. Then, this function is rendered as a part of any validation control by default. By using this function, we can check the Data Validation even before it gets posted to the server. Some times when using this functionality the page may not be posted to the server, then page has to be submitted to the server manually as given in the function or in any other way.

ViewState Vs ControlState

2008-04-23T16:51:00.000+05:30

we all know, in asp.net 1.x the web controls use the Viewstate to maintain state between postbacks. this involves more data to be transfered from and to the server. the best practice is to disbale ViewState when it is not required, but still this is problem in many other cases, suppose we use the DataGrid controls, which consumes most of the ViewState normally, the ViewState cannot be disabled because it has to support other events related to that control. the DataGrid page number, event command are stored in the Viewstate, so this is more inconvinient.
In Asp.Net 2.0, the Viewstate concept is changed and they have introduced the controlstate, which is a part of Viewstate, only for the purpose to maintain control state, not the content of it. Control state is another type of hidden state reserved exclusively for controls to maintain their core behavioral functionality, whereas view state only contains state to maintain the control's contents (UI). Technically, control state is stored in the same hidden field as view state (being just another leaf node at the end of the view state hierarchy), but if you disable view state on a particular control, or on an entire page, the control state is still propagated. this enables us to use more Web Controls, as the viewstate is maintained internally. this will not support DataGrid, because it is part of Asp.Net 1.x, the new controls of Asp.Net 2.0 will support this feature. even the viewstate is disabled the event triggered, other control properties are maintained in the controls state.

The supported controls are listed below.
Control -> Properties Stored in Control State
CheckBoxList -> PreviousItemCount, PreviousOffset
ContentPager -> CurrentPage, PageCount
DetailsView -> PageIndex, Mode, DefaultMode
FormView -> PageIndex, Mode, DefaultMode
GridView -> EditIndex, SelectedIndex, PageIndex, SortDirection, SortExpression
ListControl -> SelectedIndices
(base class for BulletedList, CheckBoxList, DropDownList, ListBox, and RadioButtonList)
LoginView -> TemplateIndex
MultiView -> ActiveViewIndex
Table -> CurrentRow, ViewMode

Partial Classes

2008-03-22T12:36:00.000+05:30

Partial Classes allow user to split the class file accross multiple source files. The benifit behind this approach is to hide the funtionality of the class. the same class can be created in may places and appropriate methods can be placed in the code file so that it derived classes can focus on significant part alone.

Interfaces

2008-03-22T12:34:00.001+05:30

Interface are a type similar to class, where it cannot have the Method Content, rather it has the definition of Method. It will not have properties and members variables. The class which inherits the interface should implement all the methods of the interface. The interface forces the derived class to implement; otherwise it will not get compiled.

The below lists some of common interfaces of .Net
1. IComparable - Implemented by types whose value can be ordered, it is used for sorting.
2. Idisposable - Defines this method to dispose of an object manually, this is important most commonly used Interface when dealing with more big objects, and also to release the object which holds the resource like database.
3. IConvertible - Enables the class to base type such as string, int or bool.
4. IClonable - Supports object copying
5. IEquatable - Allows comparing to object instances.
6. IFormatable - Provides way to convert the value of object into a formatted string. This is similar to ToString() method, but provides greater flexibility than it.