My Computer Know-How

Burn audio CDs using iTunes for Windows

2011-08-27T10:29:00.001-07:00

iTunes Version 10 Although audio CDs seem to be obsolete, there are some cases that CDs are still relevant. In this post I will explain how to create an audio CD using iTune. Unfortunately, the procedure is not that intuitive which can be attributed to the fact that CDs are not being used anymore. Create a playlist as follows: From menu choose File>New Playlist. A new entry

Using other search engines with Google Chrome

2011-06-12T21:38:00.001-07:00

Google Chrome Version 12 Chrome address bar (Omnibox) allows users to directly search the internet. Users can set a search engine as their default engine and at any time they can use the address bar to perform their searches. That’s a very helpful feature of Chrome however we sometimes require to use multiple search engines or even search content of certain sites. To accommodate this need,

Software Version Disclaimer

2009-10-01T12:54:00.000-07:00

Please note that the point made in the post might not apply to next or previous versions of the software.

Ensure web application security by correct web.config configuration

2009-06-06T21:42:00.000-07:00

In his article Bryan Sullivan explains about the most common mistakes in web.config file that leads to web site vulnerabilities. It's easy to overlook these mistakes in web.config. Moving the application from one stage to another without modifying web.config is one of the common mistakes. The following is the list of vulnerabilities; It can be used as a checklist for ensuring that the deployed

Disabling "See this location in bird's eye view" message

2009-01-18T14:45:00.000-08:00

To disable the message, add the following to your style sheet: #MSVE obliquenotification { visibility:hidden} Source: http://blogs.msdn.com/virtualearth/archive/2008/09/22/disabling-the-bird-s-eye-view-indicator.aspx

Error connecting to undo manager of source file

2008-10-02T22:40:00.000-07:00

Issue Above error message appears when user tries to debug a web application in Visual Studio 2005. Solution This error message can be fixed by simply deleting the designer file (aspx.designer.cs/aspx.designer.vb) of the page that is causing the error; you can get the page name from the complete error message you are receiving. To recreate the designer file, right click on the page ASPX file

User control properties do not show up on IDE property window

2008-10-02T22:29:00.000-07:00

Issue When you place a user control (.ascx) on a page, public properties of the user control do not appear on the IDE's property window. Solution In order for the properties to show in property window, it must be a public property and also have definition for both get and set accessors. If the above conditions are met and still the property is not accessible by property window, just close and

Internet Explorer Loads Slowly (First Tab)

2008-09-11T22:03:00.000-07:00

To fix the problem follow these steps: Open Internet Explorer. Point to Tools> Internet Options. Select Connections tab. Click on LAN settings. Uncheck Automatically detect settings.

Generics

2008-08-21T22:33:00.000-07:00

In framework 2 Microsoft introduced support for generic types. Generic can take on any type; it might sound familiar to you; objects can do exactly the same. Generics are to replace objects when possible, since they firstly improve the performance by eliminating the need to boxing and unboxing, secondly decrease the number of run-time errors caused by incorrect casting. Here is an example of

Disabling Ajax JavaScript error message

2008-08-16T12:47:00.001-07:00

By default, if an exception is thrown in the asynchronized code, ScriptManager shows the exception in a JavaScript Alert window. Although this behavior is required some times, mostly for security purposes programmer wants to hide the run-time errors from the end users even if it does not make any clear sense to them. This is especially important for public web sites which can be exposed to all

How to create a global error capturing mechanism for your web site

2008-08-16T12:43:00.001-07:00

All web sites should include a general error handling code in case anything unexpected happens. Creating this mechanism is really simple. Add Global Application Class (Global.asax) to your project if it doesn't already include one. Create the following method in the class if there isn't one. void Application_Error(object sender, EventArgs e) { Exception LastException=

Boxing and Unboxing

2008-08-10T00:50:00.001-07:00

Boxing simply means converting a value type to a reference type. Unboxing, on other hand, means converting a reference type to a value type. For more information about reference types and value types, see this post. The following is an example of boxing and unboxing: object MyObject= 2.2; //boxing double MyNumber=(double)MyObject;//unboxing To improve the performance and maintain type

Reference types and value types

2008-08-10T00:45:00.001-07:00

Value types are the variables that store the actual values as opposed to reference types that keep a reference to memory where the data is stored. Note: strings are reference types. Example: int MyValueType=123;//Value type object MyReferenceType=new object();// reference type

Choosing the right .Net Framework data collection

2008-08-03T16:09:00.001-07:00

The .Net Framework includes several useful data collection classes; choosing the right one for the task at hand is greatly crucial. In the following, I will explain about some of the most useful collections available in Framework. So, you can easily decide which one to use in different situations. These classes which are part of System.Collections namespace and System.Collections.Specialized are

How to page validate when cross-page posting

2008-07-22T20:31:00.000-07:00

It is necessary to page validate before processing the information received from the client-side. It's done with checking Page.IsValid on each page but how about when cross-page posting? You can examine PreviousPage.IsValid on the page where you post back to in order to verify validation of the first page.

Serializing and deserializing objects

2008-07-21T21:24:00.000-07:00

To serialize an object, you simply create an instance of BinaryFormatter which is part of System.Runtime.Serialization.Formatters.Binary namespace and use Serialize or Deserialize methods. The following example shows how an object can be serialized and deserialized. I used memory stream for my example; you can also use other kinds of stream such as FileStream. SerializingObject is the object

Importing namespace to the client-side code

2008-07-21T20:43:00.000-07:00

Although client side code is not recommended to contain any code-behind code, some times it's required to write some server-side code on client-side file (aspx files). One example of this situation is when using ASP.Net Repeater control; programmer might need to call a function to shape the fields to the required specification; therefore, the function has to be called on the aspx file. The need

Converting binary to Hexadecimal String in SQL Server

2008-07-20T14:50:00.000-07:00

Here is a stored procedure that can cast binary values to hexadecimal. It becomes very handy when working with binary fields. Unfortunately, SQL Server does not have a build-in cast for converting binary to hexadecimal. create procedure sp_hexadecimal @binvalue varbinary(255) as declare @charvalue varchar(255) declare @i int declare @length int declare @hexstring char(16) select

Reading and Writing to Streams

2008-07-12T03:17:00.001-07:00

In the following example, I used FileStream to explain how reading and writing to steams work. The example is self explanatory. It reads the data from TestRead.dat and writes it to TestWrite.dat. ReadCount is 0 when Read has reached the end of the file; otherwise it is 1<=ReadCount<=100. ReadCount can change every time that Read method is called in the loop. Buffer length can be modified but

Convert regular ASPX pages to content pages

2008-06-12T00:01:00.001-07:00

1) Remove DOCTYPE. 2) Remove html, head, body, and form HTML tags. 3) Add the following to the page directive: MasterPageFile="~/MyMasterPage.master" 4) Add My page contents All the page contents should be surrounded by tag. Therefore, My Page Contents should be replaced by

The operation could not be completed. Invalid FORMATETC structure

2008-06-09T23:52:00.000-07:00

Issue When you drag and drop a control from IDE toolbox to Design view, the above error message pops up. The reason for receiving this error message is that the control is not being referenced correctly. It mostly is generated by composite, third party, or MS Ajax controls. Solution In order to fix the problem: Close all Visual Studio applications that are running. Open up Visual

Error: There are no components in 'MyDll.dll that can be placed on the toolbox.

2008-06-09T18:57:00.000-07:00

Issue You will receive the above error message if there is no accessible class in your DLL and you are trying to add the DLL as a control to your IDE toolbox. Solution Make at least one of the classes public so it can be accessed from out side of the class. It is a very simple problem but if you do not know what exactly is causing it, it can get really annoying.

Fire sequence of events when a web page gets launched

2008-05-04T20:30:00.001-07:00

If we assume that Controls is a placeholder for all the controls available in a web page the following is the sequence of the events in which they are fired. 1) Page_PreInit 2) Controls_Init 3) Page_Init 4) Page_InitComplete 5) Page_PreLoad 6) Page_Load 7) Controls_Load 8) Page_LoadComplete 9) Page_PreRender 10) Controls_PreRender 11) Page_PreRenderComplete 12)

Classes vs Structures

2008-04-29T00:27:00.001-07:00

Ever wondered what are the differences between classes and structures and when you should use which one. According to Donis Marshall in his book called Visual C# 2005: The Language he mentions: "Structures are lightweight classes. Because structures reside on the stack, keep them small. Do not cache large objects on the stack. The implementation of structures in C# enforces the policy of using a

Navigating to other pages using JavaScript

2008-04-21T23:34:00.001-07:00

There are many different ways of transferring user from one page to another page without opening up a new page which don't necessarily work either IE or Firefox. The following way works with both IE and Firefox. Simply assign the new URI to href property of location. document.location.href="http://www.mycomputerknowhow.blogspot.com";

Check the browser to see whether or not cookies are allowed

2008-02-18T22:52:00.000-08:00

To see if you can save your cookies on the client's machine, you can simply use JavaScript. I did some search on the internet and realized that some people recommend using code-behind. While there is no need when you can use JavaScript, doing so will require for the web application to post back twice.Use the following code to specify cookies are allowed. It tries to leave a cookie on the client's

Converting SQL server Bit fields to Yes/No values

2008-02-18T22:27:00.000-08:00

Usually Yes/No values are saved in the database using bit data type. The problem with this kind of design is that when the table is bound a Visual Studio control, will show 0/1, instead of yes/no. For example, imagine the situation where programmer needs to save whether or not a user should be contacted, in the database and a repeater control will display that on a web page later on. The result

Visual Studio 2005 Solution Files

2008-02-06T21:52:00.000-08:00

Visual Studio 2005 has two solution files which have .sln and .suo extensions.Project files are located in My Document\Visual Studio 2005\Project folder by default. SLN file is basically a text file that can be modified manually and contains important information including project dependencies.On the other hand, SUO is a binary file that holds information about Visual Studio IDE.

Visual Studio 2005 web site types

2008-02-06T21:31:00.000-08:00

A Visual Studio 2005 web site can take one of the following types:File-basedWeb pages are placed on an arbitrary folder. To run these projects, Visual Studio temporarily creates ASP.NET development server that is capable of running the application without the need to local IIS. This is particularly suitable for the machines that do not include IIS. Windows XP Home edition is one of the examples

Evaluating a reference type variable in terms of type before casting.

2008-02-05T23:45:00.000-08:00

To evaluate a reference type variable, simply use "is" keyword. It will tell you whether or not a variable is capable of being cast to another type. If you are not sure about the type of the variable before casting it, you should use "is". For example if you are iterating through the web controls, you can utilize the following code:for each (control Ctrl in Page.Form.Controls){ if (Ctrl is

Accessing session state and application state variables from classes which are not code-behind classes in your project.

2008-02-05T23:10:00.000-08:00

In some cases developers decide to use application or session state variables in classes that are not code-behind classes. One of the examples of this situation is when programmer chooses to have a common class for all the web pages to do one specific job. The following property of HttpContext class allows you to do just that:System.Web.HttpContext.Current The above property returns

An error occurred during the parsing of a resource required to service this request. Please review the following specific parse error details and ...

2008-01-26T00:50:00.000-08:00

Error MessageParser Error Description: An error occurred during the parsing of a resource required to service this request. Please review the following specific parse error details and modify your source file appropriately. Parser Error Message: 'ProjectName.PageName' is not allowed here because it does not extend class 'System.Web.UI.Page'.When running a Visual Studio 2005 web project, the above

Passing parameters to SqlDataSource at run-time in order to excute stored procedures

2007-12-24T18:13:00.000-08:00

.Net framework allows creating SqlDataSources to execute stored procedures. The following is how to pass values to it if the stored procedure is parametrized:When creating SQL data source, choose None on Parameter Source drop-down list located on configuration data source wizard and add the following code to your code-behind.MySqlDataSource.SelectParameters["SPParameterName"].DefaultValue = "

Send Values From Code-behind to Client Side

2007-12-24T17:15:00.000-08:00

IssuePassing values to the client script is sometimes necessary. One example can be when you want to pass an error message generated by code-behind to JavaScript to be shown in an alert message box.SolutionEmbedded code blocks can be used as follows:Note: MyVariable is a variable that is accessible from out side the class.public

There is already an open DataReader associated with this Connection which must be closed first

2007-12-23T20:15:00.000-08:00

Some time ago I decide to query the database multiple times using only one connection and some Datareaders. My logic was that I can reduce the server load by doing so. Having multiple DataReaders on one Database connection is not, in fact, practical. Each Datareader can be used only with one connection and a new conncetion is needed for the next Datareader.

Reading Only Date Section of Datetime Fields values.

2007-12-23T19:56:00.000-08:00

IssueMicrosoft SQL Server stores date values in fields using datetime data type. Most programmers only need the date section while time is always attatched to the date when it's saved. When the value is read, time shows up right beside the date section.SolutionUse the following formatting for the column where the date values will be shown:DataFormatString="{0:MM/dd/YYYY}";Also remember to disable

Multiple onload event functions

2007-12-23T19:20:00.000-08:00

Sometimes it is necessary to use third party JavaScript libraries in your projects. These libraries might use some of the the JavaScript events. As a result, when you pass a new function to event to have it run when, for example page is opened, the event of library gets overwritten. Therefore, the library won't function correctly. This is the case for some of the online mapping software that use

The backup of the file or filegroup "sysft_ftcat_documentindex" is not permitted ...

2007-12-11T20:23:00.000-08:00

IntroductionAfter upgrading MSCRM database from Microsoft SQL server 2000 to 2005, the following error message may appear when creating backups of the database.IssueSQL Error Message:The backup of the file or filegroup "sysft_ftcat_documentindex" is not permitted because it is not online. BACKUP can be performed by using the FILEGROUP or FILE clauses to restrict the selection to include only

Using iframe in web pages causes the browser back button not to function correctly

2007-12-11T19:53:00.000-08:00

IntroductionBeing able to embed a web page in another web page can be really handy. Also source page of iframe can be modified which means that programmers can update the embedded page content. IssueThe problem with iframe tag is that when users click on the browsers back button, the embedded page goes one page back instead of the main page if the source URL of the iframe has been dynamically

HTML area tage and JavaScript onload event problem

2007-11-07T20:10:00.000-08:00

IssueUsing JavaScript onload event of HTML area tag, can be problematic.WorkaroundInstead of having onload event, utilize href attribute tag to address this problem. Simply change the code to:

JavaScript Onload event on Visual Studio 2005 Content pages.

2007-11-07T19:21:00.000-08:00

IssueIf you create Master/Content page setup in Visual Studio 2005, you quickly realize that Content pages do not include essential HTML tags such as Head and body. Therefore, Onload event of JavaScript cannot be used on the body tag.WorkaroundUse the following in you Content page: