.Net

Shrink SQL Server Log File

2006-08-19T10:07:00Z

I have hosted my site on a shared hosting server and have to live with the reality of limited database/web space, recently my database space was shooting up and I was really worried about it.

My posting (blogs) are not too long to reach a whopping 114 MB and so I was stunned to see the database size. After carefull investigation of each table I thought of checking at database level using the below given sp...

sp_helpdb 'DATABASE_NAME'

To my surprise I found the data file size as 10 MB and 104 MB was my log file. After googling for right way to shrink the log file, I found a really simple and perfect one...

USE DATABASE_NAME;

-- Truncate the log by changing the database recovery model to SIMPLE.

ALTER DATABASE DATABASE_NAME

SET RECOVERY SIMPLE;

-- Shrink the truncated log file to 1 MB.

DBCC SHRINKFILE (LOF_FILE_NAME, 1);

-- Reset the database recovery model.

ALTER DATABASE DATABASE_NAME

SET RECOVERY FULL;

The above solution was taken from http://msdn2.microsoft.com/en-us/library/ms189493.aspx

ASP.Net 2.0 DataList Control - Basics

2006-08-08T10:46:00Z

DataList control is a template driven data control which allows us to display a list of data in a customizable format. Simply speaking we will define how the data is to be displayed and assign a data source, the control in turn uses the data source and simply displays the data using the definition. The power of this control is realized when we need to perform some operation on the displayed data.

At the end of this post we will be able to perform some common operations using DataList control, we will walkthrough a development scenario, imagine we are developing a blog site and one of the page will allow us to manage the blog categories. We will leverage the DataList control to achieve the below given objectives

Objective

Display blog categories

Edit/Update blog categories

Delete blog categories

Add new blog category

How to...?

Hmm.. that's a very basic and common operation, we will configure our DataList control to use the ObjectDataSource control, so that it brings the blog categories from the database and hands it over to the DataList control. One important thing to note is once you configure the data source of the DataList control set the DataKeyField to a primary/unique field. This is how the control looks in default template after binding it with ObjectDatasourceControl

DataList control default template

Ok so now let's sprinkle some color on this little beauty and make it look more adorable, use the Autoformat option and select a scheme of your choice.

Here comes the fun part, we will now define how our data will be displayed, right click on the DataList control and go to "Edit Template" -> "Item Templates",

DataList control edit item template mode

In the above image you will notice that there are four sections,

Item Template

Alternating Item Template

Selected Item Template

Edit Item Template

The template names are self explanatory so I won't brag about them, edit item template is going to be our point of focus, let's just remove the "Id" field from the templates as we don't want to display that field, we are only going to display the blog category and we will be able to edit the category description.

Now let's drop a textbox control inside the edit item template and configure it's datasource, with this we are asking the DataList control "hey whenever the control is in edit mode display this textbox with the category description".

Now drop two LinkButton control's in Item Template, one for Edit and the other one for Delete and set the CommandName to "EDIT" and "DELETE" respectively.

Similarly drop two LinkButton control's in Edit ItemTemplate, one for Update and one for Cancel operation set their CommandName to "UPDATE" and "CANCEL" respectively. Below given is the snapshot

We have the UI ready for Edit,Update and Delete operations, only thing missing from the list is a way to add new blog category. For this we will use the footer template and add one Textbox control to allow the user to input the description and a Linkbutton to perform an add operation. Below given is the snapshot of the DataList control after the template modifications.

Now let's look at the event arsenal of DataList control, there are 5 events which sounds interesting, allow me to list down these events

EditCommand

UpdateCommand

CancelCommand

DeleteCommand

ItemCommand

The first four events are perfect for our needs, but what about adding new blog category this is where ItemCommand is useful. So far so good and we still have our hands neat and clean, but we will get our hands dirty with some code. Let's subscribe to all the five events and write some code.

//EditCommand
protected void DataList1_EditCommand(object source, DataListCommandEventArgs e)
{
if (e.CommandName == "EDIT")
{
DataList1.EditItemIndex = e.Item.ItemIndex;
DataList1.DataBind();
}
}

//UpdateCommand
protected void DataList1_UpdateCommand(object source, DataListCommandEventArgs e)
{if (e.CommandName == "UPDATE")
{
string sId = DataList1.DataKeys[e.Item.ItemIndex].ToString();
string sDesc = ((TextBox)e.Item.FindControl("DescText")).Text;
BlogCategory objBlogCategory = new BlogCategory(Convert.ToInt32(sId));
objBlogCategory.Description = sDesc;
BlogManager.UpdateBlogCategory(objBlogCategory);
DataList1.EditItemIndex = -1;
DataList1.DataBind();
}
}

//CancelCommand
protected void DataList1_CancelCommand(object source, DataListCommandEventArgs e)
{
DataList1.EditItemIndex = -1;
DataList1.DataBind();
}

//DeleteCommand
protected void DataList1_DeleteCommand(object source, DataListCommandEventArgs e)
{if (e.CommandName == "DELETE")
{
string sId = DataList1.DataKeys[e.Item.ItemIndex].ToString();
BlogManager.DeleteBlogCategory(Convert.ToInt32(sId));
DataList1.DataBind();
}
}

//ItemCommand
protected void DataList1_ItemCommand(object source, DataListCommandEventArgs e)
{
if (e.CommandName == "ADDNEW")
{
string sDesc = ((TextBox)e.Item.FindControl("txtCategoryDesc")).Text;
BlogCategory objBlogCategory = new BlogCategory();
objBlogCategory.Description = sDesc;
BlogManager.AddBlogCategory(objBlogCategory);
DataList1.DataBind();
}
}

How it works?

The event model is pretty straight forward, we set the EditItemIndex to the row index that needs to be edited, this is provided to us by the DataList control so there is no complexity.

During update the update command event is fired and we get the blog category description from the TextBox that holds the data by using the FindControl method.

Delete is very simple one just use the DataKeys collection of DataList and get the category id to delete.

Adding of new category seems to follow the same pattern and since this operation doesn't have a specific event associated to it we use the ItemCommand event to meet our objective.

Final output

Below given snapshot is the final output to manage our blog category, pretty neat and clean is it :)

Once you catch hold of the DataList control and play around you will find the control very usefull and a powerfull tool.

System.Net.Mail - How to add Alternate views and Embed Images

2006-07-23T20:05:00Z

System.Net.Mail provides us with a very intuitive object model to construct and send an email message.

These days almost all the web and windows email clients gives us more control over the email content we wish to view (a.k.a HTML view, plain text view). This is to make us aware that the email content we are viewing may contain explicit images or externally linked images. Now imagine the recipient have disabled HTML content in his/her settings then the email content will be displayed as is(with HTML tags).

We definitely don't want garbled text to be viewed by the recipient, now here is where the Alternate view comes to our rescue. As the name suggests it allows us to add alternate content that can be viewed by the receipient in case HTML content is disabled in his/her settings.

Similarly many web/windows email clients disable external images in the mail message to avoid linking of external images we can use the LinkedResource to embed images in our email message.

Although the core topic is about adding alternate views and embedding resources(images, etc) to an email, I will also touch upon configuration settings in web.config and Network Credentials.

MailMessage:

The MailMessage class plays a key role by wrapping all the email details like

From address
To address (collection)
CC address (collection)
BCC address (collection)
Email Subject
Email Body
Priority
Delivery notification options
Alternate views (Plain text, HTML)
Linked Resources (images, etc)

Below given is a typical code used to send an email, the code is pretty straight forward apart from the AlternateViews, LinkedResources and some SMTPClient config section.

//========================================================  
MailMessage objMailMessage = new MailMessage();

//File Attachment
if (fileUploadEmailAttachment.HasFile)
{
  objMailMessage.Attachments.Add(
  		new Attachment(
		fileUploadEmailAttachment.FileContent, 
		fileUploadEmailAttachment.FileName));

}
		
//From
objMailMessage.From = new MailAddress(txtEmailFrom.Text, 
				txtDisplayName.Text);
		
//To
objMailMessage.To.Add(new MailAddress(txtEmailTo.Text));
	
//CC
if (txtEmailCC.Text.Length > 0)
{
 objMailMessage.CC.Add(new MailAddress(txtEmailCC.Text));
}
	
//BCC	
if (txtEmailBCC.Text.Length > 0)
{
 objMailMessage.Bcc.Add(new MailAddress(txtEmailBCC.Text));
}
	
//Subject
objMailMessage.Subject = txtSubject.Text;
	
//Plain Text Alternative Email Content 
AlternateView objPlainAltView = AlternateView.CreateAlternateViewFromString(
					txtAlternateView.Text);
objMailMessage.AlternateViews.Add(objPlainAltView);
	
//HTML Alternative Email Content
LinkedResource objLinkedRes = new LinkedResource(
			Server.MapPath(".") 
			+ "\\fuzzydev-logo.jpg", "image/jpeg");
objLinkedRes.ContentId = "fuzzydev-logo"; 
	
AlternateView objHTLMAltView = AlternateView.CreateAlternateViewFromString(
				txtHTMLBody.Text, 
				new System.Net.Mime.ContentType("text/html"));
	
objHTLMAltView.LinkedResources.Add(objLinkedRes);
objMailMessage.AlternateViews.Add(objHTLMAltView);
	
//High Priority
objMailMessage.Priority = MailPriority.High;
	
//Notify On Sucessfull Delivery
objMailMessage.DeliveryNotificationOptions = DeliveryNotificationOptions.OnSuccess;
SmtpClient objSMTPClient = new SmtpClient(txtHostName.Text);
objSMTPClient.DeliveryMethod = SmtpDeliveryMethod.Network;
	
if(chkBoxEnableSSL.Checked)
  objSMTPClient.EnableSsl = true;
		
//Credentials (username, password)
string sUserName = txtEmailFrom.Text.Split('@')[0];
objSMTPClient.Credentials = new System.Net.NetworkCredential(
			sUserName, txtEmailFromPassword.Text);
	
//Send Email
objSMTPClient.Send(objMailMessage);
	
//========================================================

Now let me concentrate on the Alternateview, adding an alternate view is very easy, just create an object of the AlternateView class using the static method of the AlternateView class called CreateAlternateViewFromString passing the email text and the MIME type.

For example if we want to create a plain text view then we will do something like this

AlternateView objPlainAltView = AlternateView .CreateAlternateViewFromString(
					txtAlternateView.Text);
objMailMessage.AlternateViews.Add(objPlainAltView);

Now if we need HTML view then

AlternateView objHTLMAltView = AlternateView.CreateAlternateViewFromString(
				txtHTMLBody.Text, 
				new System.Net.Mime.ContentType("text/html"));
objMailMessage.AlternateViews.Add(objHTLMAltView);

That looks pretty simple, now the good news is the recipient will view the email message based on the email clients settings. So if HTML content is disabled then plain text message is displayed otherwise the HTML content is displayed.

Let us move forward and get our hands dirty by embedding an image in an HTML content message. In order to embed an image in our email we can use LinkedResource class, we can add this object to the LinkedResource collection of the AlternateView object.

LinkedResource objLinkedRes = new LinkedResource(
				Server.MapPath(".") 
				+ "\\fuzzydev-logo.jpg", 
				"image/jpeg");
objLinkedRes.ContentId = "fuzzydev-logo"; 
	
AlternateView objHTLMAltView = AlternateView.CreateAlternateViewFromString(
				"", 
				new System.Net.Mime.ContentType("text/html"));
objHTLMAltView.LinkedResources.Add(objLinkedRes);
objMailMessage.AlternateViews.Add(objHTLMAltView);

In the above code we are passing an image file path and also specifying the content type as an jpeg image to the LinkedResource object. Next line of code is very interesting, we are assigning a unique ContentId which will be used to set the src of our HTML image tag. In our case the content id is fuzzydev-logo and if you look at the HTML alternate view object in the constructor section we are having an image tag which refers to the same content id.

Now it's the email clients responsibility to understand the embedded resource and the reference in the image tag and display the image.

SMTPClient:

Now coming to the SMTP client configuration, let's just look in to what is the minimum configuration settings that SMTP client object expects from us.

Host name or IP address
Delivery Method (Network, Pick up directory from IIS, custom pickup directory)
EnableSsl (whether Secured Socket Layer is required)
Credentials (user name, password)

SMTPClient configuration in web.config:

	
	
	
	
	
		userName="email user name" 
		password="email passowrd" 
	/>

The above configuration helps us in quickly changing the delivery method, from mail address, host name (or IP address) , user name and password. Although the configuration is not mandatory it is the recommended way of implementing the email functionality.

Below given code doesn't depend on the web.config for it's configuration needs

	SmtpClient objSMTPClient = new SmtpClient(txtHostName.Text);
	objSMTPClient.DeliveryMethod = SmtpDeliveryMethod.Network;
	if(chkBoxEnableSSL.Checked)
		objSMTPClient.EnableSsl = true;
		
	//Credentials (username, password)
	string sUserName = txtEmailFrom.Text.Split('@')[0];
	objSMTPClient.Credentials = new System.Net.NetworkCredential(
				sUserName, txtEmailFromPassword.Text);
	
	//Send Email  
	objSMTPClient.Send(objMailMessage);

We don't need to specify the host name, etc if it's available in the web.config, this is usefull as in different part's of our application we can just use the specified configuration and if required then specify manually.

Now that deserves a round applause for those involved in the development of System.Net.Mail classes.

.Net Profile Object "my customers, my ambassadors" - Part 2

2006-06-30T22:11:00Z

For those who haven't read my previous posting on ASP.Net profile object (.Net Profile Object "my customers, my ambassadors") can read here

This has been long overdue I couldn't post sequel as I was held up with other commitments.

Anyway, let's kick start the Story Of Profiling part 2.

To be short and sweet, a good website should remember my preferrences. So that the next time I visit , I get a personalized welcome.

So how do we achieve this without using the out of the box solution provided by ASP.Net 2.0?

Create couple of tables and stored procedures to store and manipulate user profile details.
Write few classes' which will hold user's preferrence.
Write data access code to store and retrieve user's preferrence.

That's not much work and we can very well go ahead and develop our own personalization framework.

What does ASP.Net 2.0 provide?

It not only provides us with predefined set of tables, stored procedures and classes but like all other new features it's using provider model and so customization is not a painfull task. Provider model is the best thing that has happened to ASP.Net as it allows us to plug and play the implementations, this is acieved with the mixture of configuration settings and judicious use of reflection.

Let's dive in to the code and config settings to implement personalization.

Before we get our hands dirty with any code let's just set the required configuration. Below given is the sample profile properties.

The green colored config section is specific to profile. Although the elements are self describing let me explain the elements and it's attributes. By adding these elements and attributes we are asking the IDE and ASP.Net to recognize these properties as part of the profile object exposed in our Page class.

So in the above scenario our profile object will have properties like DisplayName, ShowOnlineStatus which is of type boolean and also we are asking to group PageTheme and EmailArticles inside UserInterface. So the final profile object will have the below given structure

Page.Profile.DisplayName                           = "Sachin Joshi";
Page.Profile.ShowOnlineStatus                   = true;
Page.Profile.UserInterface.PageTheme     = "Blue";
Page.Profile.UserInterface.EmailArticles    = false;

But hold a second, how did our profile object in our page got to know about the configuration and exposed these strongly-typed properties. It's not magic but the ASP.Net parser have recognized the profile configuration and have generated a class called ProfileCommon inherited from ProfileBase and have exposed the configured properties. Just check your App_Code folder and you will find a class called ProfileCommon inherited from ProfileBase.

So far so good, we have created a very simple configuration for personalization and in our web pages we will give our users the ability to save these details. But the question here is where exactly these details are saved.

Actually we have not yet configured any profile provider which helps us in storage and retrieval of these customized profile. SqlProfileProvider comes to our rescue, this class is part of the ASP.Net 2.0 framework and as the name suggests it stores and retrieves profile data to and from Sql Server.

Below given is the sample configuration of profile provider.

         connectionStringName="SqlServer2005"
         applicationName="/"
         type="System.Web.Profile.SqlProfileProvider" />

In the above config we are asking ASP.Net to use the connection string from the specified section and use the SqlProfileProvider. So when we use the profile object ASP.Net in turn will be responsible to create an instance of the right provider and use the provider to store and retrieve the profile data.

Below is the final configuration we will end up with to acieve the objective.

name="SqlServer2005"
connectionString="server=SOME_SERVER;database=SOME_DB;uid=XXXXXX;pwd=XXXXXX;"
/>

name="MYSql"
connectionString="server=SOME_SERVER;database=SOME_DB;uid=XXXXXX;pwd=XXXXXX;"
/>

         connectionStringName="SqlServer2005"
         applicationName="/"
         type="System.Web.Profile.SqlProfileProvider" />

         connectionStringName="MySql"
         applicationName="/"
         type="fuzzydev.Providers.MySqlProfileProvider" />

Note that in the above configuration there are two connection strings, one pointing to Sql Server and the other to MySql. Similarly there are two providers one for each DBMS, now we can switch to any provider by changing the defaultProvider attribute in the providers section.

Our UI need not worry about which provider or dbms is being used, this is made possible with combination of polymorphism, configuration and reflection.

Before you start playing with it there are couple of things which would be helpfull.

Serialization

By default all the primitive types are serialized as string, this can be

overriden by specifying the serializeAs attribute in the configuration

serializeAs="Binary" />

or

serializeAs="Xml" />

Allow Profiling For Anonymous Users

Profiling can also be done for anonymous users we just need to specify

allowAnonymous="true" in the configuration.

serializeAs="Xml" />

Anonymous users are tracked using cookies, this discussion will require a

whole new blog entry and so further details are deferred.

This is just a brief introduction of ASP.Net profiling, there are lot of things which needs to be looked in to like

Writing our own custom profile class by inheriting from ProfileBase and setting the attributes like allowAnonymous, serializeAs to the properties.
Writing our own profile provider for our custom data store for example Xml, Access, etc.
Migration of saved preferrences of anonymous users when they are promoted to registered users.

ASP.Net profiling is a great way of adding richness to your website with the simplicity and flexibility of plug and play components.

Excellent resource on 3-tiered data architecture with ASP.NET 2.0

2006-06-25T12:10:00Z

Scott Mitchell has put together an awesome tutorial on building and using 3-tiered date architecture with ASP.Net 2.0

It's available here

The flow of the tutorial is excellent, you can also download the tutorials in pdf format.

C# Tutorial in PDF format is available at http://www.asp.net/learn/dataaccess/datatutorials1_10cs.zip and http://www.asp.net/learn/dataaccess/datatutorials11_15cs.zip

VB.Net Tutorial in PDF format is available at http://www.asp.net/learn/dataaccess/datatutorials1_10vb.zip and http://www.asp.net/learn/dataaccess/datatutorials11_15vb.zip

If you want to kick start directly to a specific topic, I have listed down the different topics and the corresponding links for tutorial and source code for both C# and VB.Net.

Introduction

1. Creating a Data Access Layer

View this tutorial at C# VB.Net

Download source code: C# VB.Net

2. Creating a Business Logic LayerView this tutorial at C# VB.Net