David Yardy PE, MCSD.NET

Microsoft AJAX Features & Implementation Samples

David — Mon, 18 May 2009 00:46:46 GMT

There are many options within the Microsoft stack of products for AJAX type functionality. The following article covers the primary mechanisms that utilize the Microsoft out of the box Ajax functionality. Ajax must be one of the technologies used in all current web applications. The primary benefit is the improved user experience by providing quick, responsive feedback.

Core features include Ajax Client Libraries and Ajax Server Controls. These libraries and controls enable the developer to quickly implement solutions within any ASP.NET application.

I have also included in this article the examples for utilizing the Microsoft AJAX libraries using:

update panel server control
access to web service from JavaScript
access to page methods (without web service)
HttpRequest/Post from javascript.

AJAX Client Libraries

Client-Script libraries that provide features for object-oriented development which enable high level of consistency and modularity in client scripting.
- Browser compatibility
- Extensions to JavaScript such as classes, namespaces, event handling, inheritance, data types and object serialization
- Networking layer that handles communication with web based services
Sys Namespace
Javasript Shortcuts i.e. $get(‘elementId’), $addHandler, $removeHandler

Asp.Net AJAX Server Controls

ScriptManager
- Manages Javascript
- Enables partial page rendering w/UpdatePanel
- Creates client side proxies for Web Services
- Provides registration methods for scripts

<asp:ScriptManager ID="mng1" runat="server"
                    EnablePartialRendering="true|false"
                    EnablePageMethods="true|false"
                    ScriptMode="Auto|Inherit|Debug|Release"
                    ScriptPath="...">                        
                    <Scripts>
                        <asp:ScriptReference Name="script.js" Assembly="..." />
                    </Scripts>
                    <Services>
                        <asp:ServiceReference Path="~/MyWebService.asmx" />                        
                    </Services>    
       </asp:ScriptManager>

ScriptManagerProxy
- Used with Master Pages
- If you include the ScriptManager control on the master page, it can act as the ScriptManager control for all content pages. If you want to register scripts or services declaratively in a content page, you can add a ScriptManagerProxy control to the content page.
UpdatePanel
- Improves user experience of application by updating a portion of the web page thereby improving interactivity
- By default controls within the update panel can trigger the update. ChildrenAsTriggers property is by default set to true. In our example the link button is within the update panel and so can trigger the partial page update. By default any postback control inside an update panel causes an async postback
- Controls outside of the update panel can also trigger the panel contents to update. For example look at btnGo, it resides outside the panel however it is defined within the panel as a trigger/control that can force the async update to the panel contents. Reference the <asp:AsyncPostBackTrigger> element within the <Trigger> element of the updatePanel
- set EnableParitalPageRendering=”true”
- Shown here is how a timer defined outside of the panel can trigger the update panel to refresh at a defined interval

     <asp:UpdatePanel id=”panel1” runat=”server”
                             UpdateMode=”Always/Conditional”
                             ChildrenAsTriggers=”true/false”>
                      <Triggers>
                            <asp:AsyncPostBackTrigger ControlID=”timer1”/>
                       </Triggers>
                       <ContentTemplate>
                            <!—page content here -->
                      </ContentTemplate>
       </asp:UpdatePanel>
      <asp:Timer id=”timer1” runat=”server” Interval=”3000” OnTick=”OnTimerTick”/>

UpdateProgress
- provides status information about partial-page updates in the UpdatePanel controls. The content can be customized. To prevent flashing when a partial-page update is very fast, you can specify a delay before the UpdatePanel control is displayed

Update Panel Example

Code behind which responds to the button click to update a label control with the current time.

public partial class Panel : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        lblName.Text = DateTime.Now.ToString();
    }
 
    protected void lnkButton_Click(object sender, EventArgs e) {
        lblName.Text = DateTime.Now.ToString();
    }
}

Page HTML code with embedded update panel which responds to a control within the panel and a button defined as a trigger outside of the panel control.

<body>
    <form id="form1" runat="server">
    
        <asp:ScriptManager ID="ScriptManager1" runat="server" EnablePartialRendering="true"></asp:ScriptManager>
        
        <asp:UpdatePanel ID="UpdatePanel1" runat="server">
            <ContentTemplate>
                 <asp:Label ID="lblName" runat="server" CssClass="lbl" Text=""></asp:Label>
                 
                 <asp:LinkButton ID="lnkButton" runat="server" CssClass="lnk" onclick="lnkButton_Click" Text="Update"></asp:LinkButton>
            
            </ContentTemplate>        
            <Triggers> 
              <asp:AsyncPostBackTrigger ControlID="btnGo" />
            </Triggers>
        </asp:UpdatePanel>
        
        <asp:UpdateProgress ID="UpdateProgress1" runat="server" AssociatedUpdatePanelID="UpdatePanel1">
            <ProgressTemplate>
                Updating.
            </ProgressTemplate>
        </asp:UpdateProgress>
        
        <br />
        <br />
        <asp:Button ID="btnGo" runat="server" CssClass="btn" Text="Go" />
     
    </form>
</body>

Ajax and Web Service Example

Script Callable Web Service
Proxies are automatically generated
[ScriptService] Attribute

If the web service returns a complex type, the succeeded callback function receives a return value in the form of Javascript object that corresponds to the server type.

Web Service code (simple function that returns ‘Hello World’)

Web Service has [ScriptService] attribute

    [WebService(Namespace = "http://tempuri.org/")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [System.Web.Script.Services.ScriptService]
    public class MyWebService : System.Web.Services.WebService {
        public MyWebService () {
        }
     
        [WebMethod]
        public string HelloWorld() {
            return "Hello World";
        }    
    }
    

Page Code (page with button which calls js function, which in turn calls the web service defined within ScriptManager-ScriptReference tag)

<form id="form1" runat="server">
    <asp:ScriptManager ID="ScriptManager1" runat="server">
        <Services>
            <asp:ServiceReference Path="~/MyWebService.asmx" />
        </Services>        
    </asp:ScriptManager>
    <asp:Button ID="btnGet" runat="server" CssClass="btn" Text="Get" OnClientClick="update();return false" />
    
    <script type="text/javascript">
 
        function update() {
            MyWebService.HelloWorld(onCompleted, onFailed);
        }
 
        function onCompleted(result, context, methodName) {
            alert(result);
        }
 
        function onFailed(err, context, methodName) {
            alert(err.get_message());
        }
    
    </script>
 
</form>
dy>
ml>

Page Method Example

Allows javascript Ajax call back to page without web service
use EnablePageMethods=true in the ScriptManager control

The following is a sample showing a code behind static method marked with WebMethod attribute.

public partial class PageMethod : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        Response.Write(DateTime.Now.ToString());
    }
 
    [System.Web.Services.WebMethod]
    public static string update(string input){
        return input.ToUpper();
    }
}

Aspx code with a button that calls javascript, which in turn calls the page method ‘update’ to return uppercase string.

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    
    <asp:ScriptManager ID="ScriptManager1" runat="server" EnablePartialRendering="true" EnablePageMethods="true" />
    <asp:Button ID="btnGet" runat="server" CssClass="btn" Text="Get" OnClientClick="update();return false" />
 
        <script type="text/javascript">   1:  
   2:             function update() {
   3:                 PageMethods.update("test", onCompleted);
   4:                 return false;
   5:             }
   6:             function onCompleted(result) {
   7:                 alert(result.toString());
   8:             }
   9:         
</script>
    
    </form>
</body>
</html>

HTTP Requests (from Javascript) Sample

The async communication layer enables javascript to make a request over the network to any http end point by using Sys.Net.WebRequest class

The sample performs a post and get http request from javascript

Page code that initiates the javascript call GetWebRequest().

<form id="form1" runat="server">
 
<asp:ScriptManager ID="ScriptManager1" runat="server">
    <Scripts>
        <asp:ScriptReference Path="~/connect.js" />
    </Scripts>
</asp:ScriptManager>
 
    
<asp:Button ID="btnGo" runat="server" CssClass="btn" Text="GetWebRequest"  OnClientClick="GetWebRequest();return false;" />
<asp:Button ID="btnPost" runat="server" CssClass="btn" Text="PostWebRequest" OnClientClick="PostWebRequest();return false;" />
 
<div id="result">initial content</div>
 
 
</form>

Javascript (connect.js) file which performs the webrequest

// connect.js
 
var resultElement;
 
function pageLoad() {
    resultElement = $get("result");    
}
 
function GetWebRequest() {
    alert("performing web request");
    
    // Instantiate a WebRequest.
    var wRequest = new Sys.Net.WebRequest();
    
    // Set the request URL.      
    wRequest.set_url("getTarget.htm");
    alert("Target Url: getTarget.htm");
 
    // Set the request verb.
    wRequest.set_httpVerb("GET");
           
    // Set the request callback function.
    wRequest.add_completed(OnWebRequestCompleted);
 
    // Clear the results area.
    resultElement.innerHTML = "";
 
    // Execute the request.
    wRequest.invoke();      
}
 
// This function performs a POST Web request.
function PostWebRequest() {
    alert("Performing Post Web request.");
 
    // Instantiate a WebRequest.
    var wRequest = new Sys.Net.WebRequest();
 
    // Set the request URL.      
    wRequest.set_url("postTarget.aspx");
    alert("Target Url: postTarget.aspx");
 
    // Set the request verb.
    wRequest.set_httpVerb("POST");
 
    // Set the request handler.
    wRequest.add_completed(OnWebRequestCompleted);
 
    // Set the body for he POST.
    var requestBody =
        "Message=Hello! Do you hear me?";
    wRequest.set_body(requestBody);
    wRequest.get_headers()["Content-Length"] =
        requestBody.length;
 
    // Clear the results area.
    resultElement.innerHTML = "";
 
    // Execute the request.
    wRequest.invoke();
}
 
 
// This callback function processes the 
// request return values. It is called asynchronously 
// by the current executor.
function OnWebRequestCompleted(executor, eventArgs) {
    if (executor.get_responseAvailable()) {
        // Clear the previous results. 
        resultElement.innerHTML = "";
 
        // Display Web request status. 
        resultElement.innerHTML +=
          "Status: [" + executor.get_statusCode() + " " +
                    executor.get_statusText() + "]" + "<br/>";
 
        // Display Web request headers.
        resultElement.innerHTML += "Headers: ";
        resultElement.innerHTML += executor.getAllResponseHeaders() + "<br/>";
 
        // Display Web request body.
        resultElement.innerHTML +="Body:";
 
        if (document.all)
            resultElement.innerText += executor.get_responseData();
        else
            resultElement.textContent += executor.get_responseData();
    }
 
}
if (typeof (Sys) !== "undefined") Sys.Application.notifyScriptLoaded();

Target Html file used in the Get

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
    <title>Hello Page</title>
</head>
<body>
    <p> 
        Hello there. 
        I got your GET Web request!
    </p>
</body>
</html>

Post Aspx Page

<%@ Page Language="C#" AutoEventWireup="true"  %>
 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
 
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
    <title>Post Target</title>
    
    <script language="C#" runat="server">
        
        protected void Page_Load(object sender, EventArgs e)
        {
            if (HttpContext.Current.Request.Form["Message"] != null)
                LabelID.Text = 
                    HttpContext.Current.Request.Form["Message"].ToString();
        }
        
    </script>
 
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <h1>WebRequestPost Target</h1>
      
        <p>
            <asp:Textbox id="LabelID"  
                Text="test" runat="server"/>
        </p>
        
        Yes, I got your POST Web request!
        
    </div>
    </form>
</body>
</html>

ASP.NET 2.0 Compilation - Again

David — Fri, 27 Feb 2009 22:37:01 GMT

There are a few ways of deploying a .NET 2.0 ASP.NET application

using Web Site Deployment Project
using VS.NET Publish Command
using VS.NET Build Command

1.) Using VS.NET Build

ASP.NET not Visual Studio performs the build. ASP.NET builds everything, including .cs and .vb code files and places all resulting assemblies in folder structure under Temporary ASP.NET files directory. As ASP.NET does all of the compilation, the debug setting in the compilation section of the web.config controls debug or release mode. Compile with debug=true and you'll find the .pdb debugging symbol files alongside each assembly. In this scenario the Configuration Manager is obsolete (not used) and as such the only option is 'Debug'.

2.) Using VS.NET Publish

This option is available when you are ready to publish to production. The Publish command will precompile a web application and place the results into a director of your choosing (IIS/FTP/Directory). Options are available on the Publish dialog box that map to aspnet_compiler switches. The aspnet_compiler tool has option to create pdb files however this is not available on the dialog box (within vs.net). Publish always builds in release mode without pdb files. The Publish command does not change the debug setting in the web.config SO if you precompile and updateable (option 'allow this precompiled site to be updateable') web site and then update the web site in place (which will result in a dynamic compilation) those dynamic compilations will produce debug code and pdb files.

3.) Using Web Site Deployment Project (WSD)

This project allows VS.NET to use MSBUILD files provided by WSD to ask for debug and release builds. This tool uses the aspnet_compiler similar to above with the Publish option however the WSD option will change the debug setting in the web.config to false for release builds (different than the Publish option) By default the built files will be in respective debug or release directories.

Conclusion

VS.NET Build - builds web site to Temporary ASP.NET files directory with options specified in web.config

VS.NET Publish - builds to release mode (always) however does not change the compilation mode in web.config file (which can lead to less than optimum performance if site is dynamically recompiled)

Web Deployment Project - Builds based on Configuration Manager mode (debug/release) AND updates the web.config with additional options for creating debug symbols and swapping out web.config sections based on release mode

Starting jQuery – Get the downloads and patches(for Visual Studio.NET 2008)

David — Tue, 03 Feb 2009 14:51:14 GMT

1.) Download install VS.NET 2008 SP1 patch

Visual Studio 2008 SP1 has the following patch to allow IntelliSense with jQuery found here. Note: this is a patch that is applied after .NET 3.5 SP1 and Visual Studio 2008 SP1. Information about this patch can be found here.

I did find that the vsdoc.js version must match the version of jquery in order for the intellisense to function correctly. If the versions mismatch intellisense will not work.

2.) Download jQuery documentation library

3.) Download jQuery

4.) Copy both 2 and 3 to your solution Scripts folder

5.) In your aspx reference the jquery file

<script src="Scripts/jquery-1.2.6.min.js" type="text/javascript"></script>

or

<asp:ScriptManager runat="server" ID="scriptmanager1">
    <Scripts>
        <asp:ScriptReference Path="~/Scripts/jquery-1.2.6.min" />
    </Scripts>
</asp:ScriptManager>

Some Quick Tips

If you are using a master page the script reference only needs to exist in the master page
javascript intellisense will not work in user controls by default as the user control doesn’t have a reference to the js file. A work around (use the following at the top of the user control). At runtime ASP.NET will not render this tag however Visual Studio will evaluate the script and provide intellisense
<% if (false) { %>
<script src=”../Scripts/jquery-1.2.6.min.js” type=”text/javascript”></script>
<% } %>
a recommended method of including js files is to create one js file which entail will include references to any number of specific js files, then on your web page include a reference to this one single js file
<reference path=”~/Scripts/jquery-1.2.6.min.js” />
a good approach is to remove the version number from the jquery files to allow easier updates to these files in the future

Path(s) for Script References

File-Relative Paths i.e. ../../file.js This type of path is relative to the currently loaded file. Support - ASP.NET Web forms / MVC
App-Relative Paths i.e. ~/folder/file.js Is calculated from the base of your application. ASP.NET Web forms supports this type of path however the path must be within a scriptreference tag or select asp.net controls which have runat=”server”
Site-Relative Paths i.e. /folder/file.js Is calculated from the base of your site. Supported by ASP.NET Web forms / MVC however is not supported by Visual Studio
Absolute Paths i.e. http://site/folder/file.js Supported by ASP.NET Web forms / MVC and Visual Studio

If using Visual Studio(ASP.NET Web forms) recommended to use App-Relative paths ~/folder/file.js. If using MVC use file-relative paths.

SQL Server - Comparing Tables (Merge, Except, Intersect)

David — Tue, 03 Feb 2009 01:56:54 GMT

I had a need to compare two SQL Server table for differences between them. I started using .NET dataset features (merge, acceptchanges, getchanges) as follows:

        Dim data1 DataSet = GetData1() 
        Dim data2 DataSet = GetData2() 
 
        Dim ds As New DataSet
        ds.Merge(data1)
        ds.AcceptChanges()
        ds.Merge(data2)
        ds.GetChanges(DataRowState.Modified)

There are a few gotcha's with the above code. The primary problem was that both tables must have primary keys defined. I figured ok, I could create primary keys through code for the related DataTables however I soon realized that there were duplicate rows within the tables.

SQL Server 2005 has Except and Intersect functions (http://msdn.microsoft.com/en-us/library/ms188055(SQL.90).aspx) that return distinct values by comparing the results of two queries. The entire row is compared against another row from another table.

Except returns any distinct values from the left query that are not found on the right query.
Intersect returns any distinct values that are returned by both the query on the left and right sides.

In order to use the number and order of the columns must be the same in the queries and also the data types must be comparable.

To return all rows in table1 that do not match exactly the rows in table2, you can use Except ...
select * from table1 except select * from table2

(likewise to find the opposite just reverse the table names above)

To return all rows in table1 that match exactly what is in table2, using Intersect...
select * from table1 intersect select * from table2

Combining the above two... (the following will return the differences)
select 'table1' as tblName, * from
(select * from Table1 except select * from Table2) x
union all
select 'table2' as tblName, * from
(select * from Table2 except select * from Table1 ) x

If you are fortunate to have primary keys you can of course still use IN/NOT IN type queries however it seems that performance is much improved with the Except/Intersect approach.

ASP.NET AJAX Client Library - Global Shortcut List

David — Sun, 01 Feb 2009 18:58:34 GMT

Recently, Microsoft released their ASP.NET AJAX Framework which allows developers to build AJAX applications more easily. ASP.NET AJAX consists of two pieces.

1.) Microsoft AJAX Library - contains a set of script files that provide common functions and an OO programming framework

2.) ASP.NET 2.0 AJAX Extensions - includes a set of server controls that allows developers to add AJAX functionality by dragging and dropping controls onto a page

The following are brief descriptions of the javascript extensions made available by the AJAX Client Library by Namespace.

Global Namespace - contains members and types that extend base JavaScript objects.

Array Extensions (add, addRange, clear, clone, contains, dequeue, enqueue, forEach, indexOf, insert, pars, remove, removeAt)

Boolean Extension (parse - converts a string into a Boolean)

Date Extension (format, localeFormat, parseInvariant, parseLocale)
        var today = new Date();
        alert (today.format('D'));

        d - Short date pattern (05/10/07)
        D - Long date pattern (Thursday, 10 May 2007)
        t - Short time pattern (18:05)
        T - Long time pattern (18:05:12)
        F- Full date pattern (Thursday, 10 May 2007 18:05:12)
        M - Month and date pattern (May 10)
        s - Sortable date and time pattern (2007-05-10T18:05:12)
        Y - Year and month pattern (2007 May)

Error Extensions (argument, argumentNull, argumentOutOfRange, argumentType, argumentUndefined, create, invalidOperation, notImplemented, parameterCount, popStackFrame)

Number Extension (format, localeFormat, parseInvariant, parseLocale)

        p - number is converted to a string that represents a percent
        d - converted to a string of decimal digits
        c - converted to a string that represents a currency
        n - converted to a string of the form "-d,ddd,dd"

        var num = Number.parseInvariant("130.33");
        alert (num.localeFormat("c")); // $130.33

Object Extensions (getType, getTypeName)
        getType - returns the type of specified object
        getTypeName - returns the type name of an object

String Extension (endsWith, format, localeFormat, startsWith, trim, trimEnd, trimStart)

Sys Namespace

         Sys - root namespace containing some base classes such as Sys.CultureInfo
                  Application - objects/methods that expose client events and manage client components
                  ApplicationLoadEventArgs - container object for arguments of the Application Load event
                  CancelEventArgs - base class for events that can be canceled
                  Component - base class for all asp.net ajax objects including Control class and Behavior class
                  CultureInfo - object that can be used to provide locale specific functionality
                  Debug code - debugging and tracing functionality
                  EventArgs - used for storing event arguments
                  EventHandlerList - collection of client events for a component containing event names and handlers
                  PropertyChangedEventArgs - contains event arguments associated with changed properties
                  StringBuilder - facilitates more efficient string concatenation

         Sys.Net - provides networking and communication support
         Sys.UI - contains set of classes for UI support
         Sys.Services - support for asp.net application services such as login/authentication
         Sys.Serialization - provides support for data serialization/Json
         Sys.WebForms - contains classes for async page loading

Shortcut	Description
$addHandler	Shortcut to Sys.UI.DomEvent.addHandler method
$addHandlers	Shortcut to Sys.UI.DomEvent.addHandlers method
$clearHandlers	Shortcut to Sys.UI.DomEvent.clearHandlers method
$create	Shortcut to Sys.Component.create method
$find	Shortcut to Sys.Application.findComponent method
$get	Shortcut to Sys.UI.DomElement.getElementId method
$removeHandler	Shortcut to System.UI.DomEvent.removeHandler method

.NET 3.5 SP1 : How to tell if it is installed?

David — Sun, 25 Jan 2009 17:18:29 GMT

Ever want to know if you have 3.5 SP1 installed? Shown below are two ways to determine.

1.) Take a look at HKLM\SOFTWARE\MICROSOFT\NET Framework Setup\NDP\v3.5

Shown below are two servers. The top one does not have SP1 installed while the lower one does.

2.) An easy way to see if you have 3.5 SP1 installed is to navigate to http://www.hanselman.com/smallestdotnet/ Near the top of this page you will be given an indication if you have the latest installed.

If you do not have it installed you can use the following link to navigate you to Microsoft Downloads for Microsoft .NET Framework 3.5 Service Pack 1. This link will installed a small installer that will need to be executed. A wizard will step you through the installation and additional downloads.

If you prefer a complete download of this SP1 you can use this link.

SQL Server – Find all Columns in a Database where…

David — Fri, 23 Jan 2009 01:35:54 GMT

Where the column name matches exactly…
SELECT name FROM sysobjects WHERE id IN ( SELECT id FROM syscolumns WHERE name = '{text}' )

Where the column name is like…
SELECT name FROM sysobjects WHERE id IN ( SELECT id FROM syscolumns WHERE name like '%{text}%' )

The following will show all occurrences of the column in any object
SELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE COLUMN_NAME LIKE '%doctorid%'

SQL Server : Find SQL Object Names within a Database

David — Thu, 22 Jan 2009 23:37:38 GMT

I was returning to an old database and I wanted to find all instances of a particular column name. The following SQL is a very fast way to output the object name (with additional data) for locating the item of interest. Of course you can make more elaborate by filtering query.

SELECT sc.[name] AS column_name, so.[name] , *
FROM syscolumns sc INNER JOIN sysobjects so ON sc.id=so.id WHERE sc.[name] LIKE '%TestColumnName%'

Escape Sequences and Verbatim Strings in C#

David — Mon, 29 Dec 2008 17:30:56 GMT

C# uses special escape sequences within a string to signify that what follows is to be treated differently. The special character is the backslash \. This character says to treat whatever follows it as though it were part of the string itself.

string msg = "Spot the dog said: \" get that dog bone\""; // knowing this the following is good syntax:

Spot the dog said: "get that dog bone" //output

List of C# Escape Sequences

\" Display a double quotation mark
\' Display a single quotation mark.
\\ Display a backslash.
\0 Null (non-printing).
\a Alarm (beep terminal alarm).
\b Backspace (back up one character position).
\f Form feed (advance to next page).
\n Newline (advance to next line).
\r Carriage return (move to left margin).
\t Tab (advance one tab space, often eight characters).
\v Vertical tab.

C# provides a way to avoid 'escaping' characters in strings. You can use the verbatim string literal character @ to tell VS.NET to build the string exactly as it appears.
string msg = @"go to c:\temp"; // this would work

The verbatim string can be used to allow a single string to span more than one line i.e.

string msg = @"this is great
to be under
the sun";

Enterprise Library Components 4.1 (Contents of the download)

David — Fri, 26 Dec 2008 23:44:12 GMT

The default installation folder C:\Program Files\Microsoft Enterprise Library 4.1 - October 2008

Bin - contains the binaries you can use in the application. Also the configuration editor EntLibConfig.exe which can be used to create and edit configuration files for EntLib
Docs - documentation
Src - contains the installer file for the Enterprise Library source file
Visual Studio Integration - contains binaries that make the configuration Editor available in Visual Studio

The installer also puts the original source code in C:\EntLib41Src

bin - contains the same as the bin above
Blocks - contains a solution that houses all 42 Enterprise Library projects. There is also a second solution that additionally contains unit test projects and the actual unit tests to verify correct working of Enterprise Library as you change it. This is a great value that allows you to feel comfortable editing this pile of code while being able to prove you have not broken anything
Lib - contains object builder and unity binaries that you can use in your application independent of EntLib
Quick Starts - contains sample code in both C# and VB.NET that you can use to see available functionality of EntLib and how to use it in your own applications.
Scripts - contains batch files to amongst others compile EntLib from the source, register assemblies and to install Northwind database for the quick starts

Enteprise Library 4.1 can be found http://msdn.microsoft.com/en-us/library/dd203099.aspx

Auto-Implemented Properties c# .NET 3.0+

David — Fri, 26 Dec 2008 18:00:14 GMT

Instead of the following typical property setter/getter

private string courseName;
pubic string CourseName{
get { return courseName;}
set { courseName = value;}
}

//Auto-Implemented property implicitly creates an instance variable for property CourseName
public string CourseName {get; set;}

unable to use the private variable for this property (hidden from developer)
developer can only reference within the class via CourseName

This is a reasonable approach for quick prototyping of properties only.

Anonymous Objects or Types (.NET 3.0+ )

David — Fri, 26 Dec 2008 17:53:09 GMT

Details...

an anonymous type declaration begins with the new keyword followed by a member-initialzer list in braces {}

the compiler generates a new class definition that contains the properties specified in the new member-initializer list

all properties of an anonymous type are public and immutable

anonymous type properties are read-only (you cannot modify a properties value once the object is created)

each properties type is inferred from the values assigned to it

the compiler defines a ToString method that returns comma-separated list of property-name = value pairs

Equals method compares the properties of two or more anonymous types

Examples...

//Create a 'person' object using an anonymous type
var bob = new { Name = "Bob", Age = 37 };

bob in this case is the anonymous type and the types of the properties are inferred by the value assigned.

//display information (note here however that the ToString is not required as a ToString method is automatically defined and is the anonymous type)
Console.WriteLine("Bob:" + bob.ToString());

//the ToString() method would output the following
Bob: { Name = Bob, Age = 37 }

var steve = new { Name = "Steve", Age = 36 };

//the compiler is able to recognize the anonymous type for bob and steve are identical and of the same class by the fact that the properties and types were identical for both bob and steve

//the anonymous type also creates an equals method that is capable of comparing all objects of this anonymous type (so name and age properties will be compared)
Console.WriteLine(bob.Equals(steve) ? "equal" : "not equal"));

The output from the is "not equal".

CSS Lost, Missing, Absent, Gone after Postback in Asp.NET

David — Sat, 20 Dec 2008 14:40:33 GMT

I have a generic function in one of my helper libraries that allows me to open a new browser window when a button is selected. The button posts back to the server runs some code and opens a new window. I often use this sort of thing on a reporting page allowing me to post some search criteria and open a new window (a pdf report).

I found this type of helper function useful however I found that I was losing my CSS after the postback.

To avoid losing the css keep the following in mind:

ensure that your css files are include declaratively in your aspx page (not through code behind)
use Page.ClientScript.RegisterStartupScript(this.GetType(),”name”,script); (Not Response.Write)

The end helper function looks something like the following:

    /// <summary>
    /// redirect to a new page from codebehind
    /// </summary>    
    static public void RedirectToNewWindow(string url, System.Web.UI.Page page) {        
        string script = "<script>window.open('" + url + "');</script>";
        page.ClientScript.RegisterStartupScript(page.GetType(), "redirectscript",script);        
    }

Testing Web Service(ASMX) Remotely (yes, you can!)

David — Tue, 09 Dec 2008 17:45:49 GMT

Often we test web services by either locally on our workstations or remoting to the server and accessing the asmx page. If you try to access the asmx remotely however you are not given the option to test the server (by using the server url address). By adding the following code the <system.web> section of asmx web site web.config you can now test your services remotely.

<webServices>
       <protocols>
           <add name="HttpSoap12"/>
           <add name="HttpSoap"/>
           <add name="HttpGet"/>
            <add name="HttpPost"/>
       </protocols>
</webServices>

The above code addresses the issue related to "The test form is only available for requests from the local machine." error message.

String Literals and C#

David — Sun, 07 Dec 2008 18:19:44 GMT

I was looking for some utility that would take a very long string and convert it to vb.net or c# with line continuation(s) characters. String literals to the rescue. C# supports two forms of string literals: regular string literals and verbatim string literals.

A regular string literal consists of zero or more characters enclosed in double quotes, as in "hello", and may include both simple escape sequences (such as \t for the tab character) and hexadecimal and Unicode escape sequences. In c# regular strings can only span multiple lines with syntax similar to the following:

string sql = “SELECT customer “ +
“FROM customers “ +
“WHERE custId=10”;

A verbatim string literal consists of an @ character followed by a double-quote character, zero or more characters, and a closing double-quote character. A simple example is @"hello". In a verbatim string literal, the characters between the delimiters are interpreted verbatim, the only exception being a quote-escape-sequence. In particular, simple escape sequences and hexadecimal and Unicode escape sequences are not processed in verbatim string literals.

The above sample can be replaced with the ‘literal’ designated by the @ symbol as follows:

string sql = @“SELECT
FROM customers
WHERE custId=10”;