.NET Notes

determining row in an item template using the row index:

2012-02-02T12:37:00.000-08:00

http://www.ezzylearning.com/tutorial.aspx?tid=7597714

javascript:

row = $(editButton).parent().parent();
id = $("#id", row).text();
name = $("#name", row).text();
fee = $("#fee", row).text();
row.addClass("highlightRow");

html template:

html notes

2012-02-02T12:36:00.001-08:00

RULES=ROWS indicates that there should be borders between rows but not between columns.

RULES = ROWS

diagrams

2012-02-02T07:29:00.001-08:00

database

http://edn.embarcadero.com/article/31863

association -- a relationship between instances of the two classes. There is an association between two classes if an instance of one class must know about the other in order to perform its work. In a diagram, an association is a link connecting two classes.
aggregation -- an association in which one class belongs to a collection. An aggregation has a diamond end pointing to the part containing the whole. In our diagram, Order has a collection of OrderDetails.
generalization -- an inheritance link indicating one class is a superclass of the other. A generalization has a triangle pointing to the superclass. Payment is a superclass of Cash, Check, and Credit.
An association has two ends. An end may have a role name to clarify the nature of the association. For example, an OrderDetail is a line item of each Order.

A navigability arrow on an association shows which direction the association can be traversed or queried. An OrderDetail can be queried about its Item, but not the other way around. The arrow also lets you know who "owns" the association's implementation; in this case, OrderDetail has an Item. Associations with no navigability arrows are bi-directional.

2012-02-02T06:22:00.000-08:00

finally different mvc mvvm , etc. explained simply:

http://wpftutorial.net/MVVM.html

set culture

2012-01-31T23:41:00.001-08:00

CultureInfo ci = CultureInfo.CreateSpecificCulture(prefix);
Thread.CurrentThread.CurrentCulture = ci;
Thread.CurrentThread.CurrentUICulture = ci;

XDcoument Linq to AXML

2012-01-31T23:10:00.001-08:00

public class FeedDefintion
{
public string State { get; set; }
public string Zip { get; set; }
}
public void ProcessRequest(HttpContext context)
{
//write your handler implementation here.
XDocument xdoc = XDocument.Load(context.Server.MapPath("Listings.xml"));

var feeds = from feed in xdoc.Descendants("Categories")
select new FeedDefintion { State = feed.Element("State").Value, Zip = feed.Element("Zip").Value };
List fl = feeds.ToList();

System.Web.Script.Serialization.JavaScriptSerializer oSerializer =
new System.Web.Script.Serialization.JavaScriptSerializer();

string sJSON = oSerializer.Serialize(fl);

//context.Response.ContentType = "application/json";
context.Response.ContentType = "application/json";

sJSON = context.Request.QueryString["callback"] + "(" + sJSON + ");";
context.Response.Write(sJSON);
}

Creates an instance of the specified type

2012-01-22T23:15:00.000-08:00

Activator class is extremely powerful:

Contains methods to create types of objects locally or remotely, or obtain references to existing remote objects.

Activator.CreateInstance

Hashtable v. Dictionary

2012-01-22T14:32:00.001-08:00

The Dictionary(Of TKey, TValue) and ConcurrentDictionary(Of TKey, TValue)classes have the same functionality as the Hashtable class. A Dictionary(Of TKey, TValue) of a specific type (other than Object) provides better performance than a Hashtable for value types. This is because the elements of Hashtable are of type Object; therefore, boxing and unboxing typically occur when you store or retrieve a value type. The ConcurrentDictionary(Of TKey, TValue)class should be used when multiple threads might be accessing the collection simultaneously.

SQL Notes

2012-01-12T15:23:00.000-08:00

Find all references of a given stored proc or a given string.

syscomments has the body text for all user stored procs in the system.
So you may search all stored procs that contain a given text.
Suppose you want to see all references for a stored proc named up_MyProc.
You may accomplish this as follows:

declare @keyword nvarchar(100)
set @keyword = 'up_MyProc' -- Enter the key word here like 'OptInInd'
SELECT distinct 'sp_helptext ' + o.name
FROM syscomments s, sys.objects o
where s.id = o.object_id
and o.type = 'P'
and charindex(@keyword, s.text) > 0

Rebooting With remote desktop

2011-06-11T02:20:00.000-07:00

You remote Windows computer appears hung and can't even bring up the Start Menu. How do you log off or reboot the machine?

Do a CTL-ALT-END this brings up the Task Manager allowing you to reboot or log off.

Modifying HTML content before on Render

2011-05-03T11:27:00.001-07:00

You could modify the HTML that is about to be rendered to a page using the ASP.NET Render event. For example, below we add an onclick event to every a href tag on the page:

///

/// Add an onclick handler to each link. Allows omniture to trace user clicks and navigation with s_objectID.
/// Exceptions: if onclick exists do not override or add another one to the chain.
///

protected override void Render(System.Web.UI.HtmlTextWriter writer)
{

System.IO.StringWriter stringWriter = new System.IO.StringWriter();
HtmlTextWriter htmlWriter = new HtmlTextWriter(stringWriter);
base.Render(htmlWriter);
string html = stringWriter.ToString();

// get to the first a tag and start processing from there
int startPoint = html.IndexOf("
// is there already an onclick handler on some tag in this page
bool hasOnclick = html.IndexOf("onclick=", StringComparison.InvariantCultureIgnoreCase) > -1;

// get to the href and add an onclick handler unless one already exists
startPoint = html.IndexOf("href=\"", startPoint);
int ihref2 = 0;
string link;

// distniguishes links within different pages
string linkExtension;
string[] pathseg = Request.Url.Segments;
if (pathseg.Length > 0)
{
linkExtension = pathseg[pathseg.Length - 1];
linkExtension = linkExtension.Replace(".", "");
}
else
linkExtension = String.Empty;

while (startPoint > -1)
{
if (hasOnclick)
{
int idx1 = html.IndexOf(" int idx2 = html.IndexOf(">", idx1 + 1);
string atag = html.Substring(idx1, idx2 - idx1);

// is this an if (atag.IndexOf("onclick", StringComparison.InvariantCultureIgnoreCase) > -1)
{
// move to the next tag. Do not override existing onclick
startPoint = startPoint + 7;
startPoint = html.IndexOf("href=\"", startPoint);
continue;
}
}

startPoint = startPoint + 7;
ihref2 = html.IndexOf("\"", startPoint);
if (ihref2 > -1 && ihref2 > startPoint)
{
link = html.Substring(startPoint, ihref2 - startPoint).Replace("http", "").Replace("\\", "").Replace(@"/", "").Replace("\"", "").Replace("'", "").Replace(".", "").Replace("(", "").Replace(")", "").Replace(":", "");
ihref2++;
html = html.Substring(0, ihref2) + " onclick=\"s_objectID='" + link + linkExtension + "'\" " + html.Substring(ihref2);
startPoint = html.IndexOf("href=\"", ihref2); // get the next href - ihref2 is > startPoint
}
else
startPoint = -1;
}

writer.Write(html);
}

return key event processing in javascript

2008-10-10T03:46:00.001-07:00

function retkey(ev) {

if (ev == null)
ev = window.event;
var key = null;
if (ev.keyCode)
key = ev.keyCode;
else if (ev.which)
key = ev.which;

if (key != null && key == 13)
return ClientValidate();

return true;
}

Calculating absolute position

2008-09-25T19:04:00.000-07:00

// here is a Javascript routine that calculates the absolute position of an html
// element by recursively traversing the parent dom elements
// (works in IE, Firefox, Safari , etc.)

Map.Drawing.Point.prototype.addAbsolutePosition = function(obj) {
var X, Y;
var cur;
if (!obj) {
return this;
}
else
{
X=parseInt("0" + this.x);
Y=parseInt("0" + this.y);
var o = obj;
if (o.offsetParent) //then this object has a container that affects its position
{
while (o.offsetParent)
{
X += parseInt(o.offsetLeft);
Y += parseInt(o.offsetTop);
o = o.offsetParent; //traverse the hierarchy upward
}
}
else if (o.x || o.y) //no container but an absolute position
{
if (o.x) X += parseInt(o.x);
if (o.y) Y += parseInt(o.y);
}

this.x = X;
this.y = Y;

return this;
}
};

301 Redirects

2008-09-16T18:49:00.001-07:00

To fully retire a page and redirect to a new page SEO (Search Engine Optimization) recommends 301 redirects (as opposed to the regular 303 redirects).

Below is the essential code fragment in Global.asax of the .NET framework to issue a 301 SEO friendly redirect:

// below we are redirecting to www.mynewurl.com
protected void Application_BeginRequest(Object sender, EventArgs e)
{
string oldserver = HttpContext.Current.Request.Url.AbsoluteUri;

// Check whether it is an old url
if (oldserver.IndexOf("myoldurl.com") > -1)
{
HttpContext incoming = HttpContext.Current;

incoming.Response.StatusCode = 301;
incoming.Response.AddHeader("Location", "http://www.mynewurl.com"));
incoming.Response.End();
return;
}

}

// end of 301 redirect logic

In .NET this could better be done with an httpModule. Coding this as an httpModule (instead of in Global.asax) is beyond the scope of this article.

Search Engine Optimization (SEO)

2008-08-30T09:43:00.000-07:00

1- Use the H tages (H1, H2, H3, H4, etc.) tags for important keyword text
- You may repeat your keywords throughout the page (increases density) and bolding and italizing them is also benefitial.
- Keywords at top, but repeat them at bottom. the GO logic is that if something is said at top and repeated at bottom it must be important.
- Use rel="nofollow" on href tags
- All lower case (or same case) file names.
- Do not use "_" in filenames; instead use "-"

Optimizing ASP.NET and HTML pages

2008-01-30T14:45:00.000-08:00

A comprehensive checklist will serve you well:

- Turn ViewState off on page and control levels when not needed

- Turn SessionState off:
"Session objects consume valuable resources. By turning off sessions, you can improve the performance and scalability of your ASP Web application. You can turn off session state either for the whole Web site or for specific ASP pages."
http://support.microsoft.com/kb/244465

- Alternatives to server controls include simple rendering, HTML elements, inline Response.Write calls, and raw inline angle brackets (<% %>).
(http://msdn2.microsoft.com/en-us/library/ms998549.aspx)

- Especially if not compressing html:
Remove or reduce white space. Removing white spaces can dramatically reduce the size of your pages. Less white space did have about a 5-10K impact on move.com home page when viewed on the browser File-Properties.

-Avoid long control names; especially ones that are repeated in a DataGrid or Repeater control. Control names are used to generate unique HTML ID names. A 10-character control name can easily turn into 30 to 40 characters when it is used inside nested controls that are repeated.

- Use Output caching for user controls , pages, etc. (%@OutputCache directive
)

- Use static properties instead of the Application object to store application state.
(http://msdn2.microsoft.com/en-us/library/ms998549.aspx)

- Use client side validation to avoid unnecessary server hits

-Avoid Creating Deep Hierarchies of Controls (see http://msdn2.microsoft.com/en-us/library/ms998549.aspx#scalenetchapt06_topic11)

Checklist: ASP.NET Performance:
http://msdn2.microsoft.com/en-us/library/ms998596.aspx

flushing DNS in Windows and MAC OS

2008-01-03T10:41:00.000-08:00

Windows:

ipconfig /flushdns

MAC (before Leopard):
sudo lookupd -flushcache

MAC - Leopard:
dscacheutil -flushcache

Efficient .ASPX pages

2007-08-02T23:25:00.000-07:00

A comprehensive checklist would be great. Slowing tickets could be assigned to violators and we could better arrive and agree on guidelines; otherwise, what is known may still be ignored or forgotten.

So its worth mentioning the following (and more):

- Turn ViewState off on page and control levels when not needed
- Turn SessionState off:
"Session objects consume valuable resources. By turning off sessions, you can improve the performance and scalability of your ASP Web application. You can turn off session state either for the whole Web site or for specific ASP pages."

http://support.microsoft.com/kb/244465

- Alternatives to server controls include simple rendering, HTML elements, inline Response.Write calls, and raw inline angle brackets (<% %>).

(http://msdn2.microsoft.com/en-us/library/ms998549.aspx)

- Especially if not compressing html:
Remove or reduce white space. Removing white spaces can dramatically reduce the size of your pages. Less white space did have about a 5-10K impact on move.com home page when viewed on the browser File-Properties.

-Avoid long control names; especially ones that are repeated in a DataGrid or Repeater control. Control names are used to generate unique HTML ID names. A 10-character control name can easily turn into 30 to 40 characters when it is used inside nested controls that are repeated.

- Use Output caching for user controls , pages, etc. (%@OutputCache directive
)

- Use static properties instead of the Application object to store application state.
(http://msdn2.microsoft.com/en-us/library/ms998549.aspx)

- Consider html size and preformance differences such as:
a label with onclick vs an href onclick
a Literal vs a label's final html

-Use Page.IsPostBack to Minimize Redundant Processing
- Use client side validation to avoid unecessary server hits

-Avoid Creating Deep Hierarchies of Controls (see http://msdn2.microsoft.com/en-us/library/ms998549.aspx#scalenetchapt06_topic11)

http://msdn2.microsoft.com/en-us/library/ms998596.aspx

Reading a .csv or a comma-delimited .txt file using SQL

2007-05-04T17:37:00.000-07:00

Sample code for Reading a .csv or a comma-delimited .txt file using SQL:

Below:
1) StoragePath is the absolute path to the .csv file.
2) Substitute MyFileName.csv with your file name.

using System.Data.Odbc;
public void ReadData()
{
string StoragePath = @"c:\test";
string strSQL = "Select * from MyFileName.csv";
OdbcConnection conn = new OdbcConnection(
@"Driver={Microsoft Text Driver (*.txt; *.csv)};DBQ="+StoragePath);

conn.Open();

OdbcDataAdapter da = new OdbcDataAdapter(strSQL, conn);

DataSet ds = new DataSet();

da.Fill(ds);

conn.Close();
}

Class does not support automation

2007-04-29T23:03:00.000-07:00

Javascript: "Class does not support automation". Occurs when opening a popup.

Solution:

http://www.anetforums.com/posts.aspx?ThreadIndex=8917

regsvr32 Shdocvw.dll
regsvr32 Shell32.dll
regsvr32 Oleaut32.dll
regsvr32 Actxprxy.dll
regsvr32 Mshtml.dll
regsvr32 Urlmon.dll

Calling a Windows or DOS Process from a Web Application

2006-11-09T01:01:00.001-08:00

Finding duplicates in a table using SQL

2006-11-09T00:57:00.001-08:00

In Transact SQL duplicate rows for a table mytable based on column mycolumn may be found as follows:

SELECT myfield, COUNT(*)
FROM mytable
GROUP BY myfield
HAVING COUNT(*) > 1;

Caching in .NET handlers

2006-11-09T00:56:00.001-08:00

Browser caching of a .NET handler may prevent the server-side code of the handler to be invoked. A user requesting an action for a second time may not get his/her results because your handler is cached and the invocation does not occur.

This problem also depends on how long the handler is being cached. If in your browser you delete all offline content (Tools - Internet Options - Delete Fiels - Check Delete all offline content - OK - OK) then your handler is no longer cached.

The solution is to add the following code to the ProcessRequest function of the handler:

// Don't allow this response to be cached by the browser.
context.Response.Cache.SetCacheability(HttpCacheability.NoCache);
context.Response.Cache.SetNoStore();
context.Response.Cache.SetExpires(DateTime.MinValue);

Isaac Levy, August 2006

RegisterForEventValidation and event validation

2006-11-09T00:55:00.000-08:00

When submitting pages in ASP.NET 2.0 you may get a validation error.

"Invalid postback or callback argument.
Description: An unhandled exception occurred during the execution of the current web request. "

Event validation is enabled using in configuration or <%@ Page> EnableEventValidation="true" %> in a page

For security purposes it is not advisable to turn off validation.

The error occurs for one of the following reasons:

1) You have a server-side asp control (such as a drop down) that you populate using javascript. The server-side rendered values do not match the populated values since you populated the drop down on the client-side.

2) You have an invalid HTML on the page. (For example, you may have a closing /form tag without a corresponding beginning form tag!). You may want to run your HTML through one of many free HTML validators on the Internet.

In the first case where you have populated your drop down with Javascript you could eliminate the error by calling the RegisterForEventValidation function. RegisterForEventValidation can only be called during Render().
You will need to register each valid value that you use in the Javascript code. For example if you populate a drop down with U.S. state abbreviations, you need to register each state code on the server side as follows:

Page.ClientScript.RegisterForEventValidation(ddlState.UniqueID, "AK");
Page.ClientScript.RegisterForEventValidation(ddlState.UniqueID, "AL");
Page.ClientScript.RegisterForEventValidation(ddlState.UniqueID, "CA");

And so forth ...

You may also want to consider the following as another workaround:
(Check the following article for more details: http://msdn2.microsoft.com/en-us/library/w1sw53ds.aspx)

1)If you want to display strings in your application but do not trust them, apply HTML encoding to them when the strings are written back in a response. For example, with encoding, the tag b becomes <b>. You might do this if the strings that you are displaying are from a database whose contents you are not sure that you can trust.

2)If you want your application to accept some HTML (for example, some formatting instructions from users), you should encode the HTML at the client before it is submitted to the server.

@Copyright 2006, Isaac Levy

Cool Mouse Over Effects

2006-11-09T00:54:00.000-08:00

Ever wanted to show a popup information window when the mouse rolls over an
image, a grid cell, a hyper link or any other UI control?

In this article we display a table (window) when the user rolls over an ASP.NET
server-side control.

The window to display is contained in a "div" tag. The content of the "div" tag
may be changed at runtime using the javascript "innerHtml" property. These will
be described later.

First, We need to define a style for the "div" tag. The style could be defined
within the html HEAD tags as follows:

<STYLE><br />#rollover { position: absolute; left: 0; top: 0; Z-INDEX: 101;}<br /> </STYLE><br />

Above position:absolute is necessary. The position of
the <div> tag will change as we move the mouse over different controls.
position:absolute position insures
the div will be positioned at the new location.

Next we define two javascript functions for showing and hiding the div:

Above the showimage() function will be called on the onmouseover event.
window.event.x and window.event.y specify the location of the mouse during the
onmouseover event.

The coordinates of the "div" will be set using the x, y mouse location. To the
mouse x location we simply add extra space so that the window will be displayed
a bit to the right of our control.

The content of the "div" is changed using the innerHTML attribute as follows:

Next, In the .ASPX file define your rollover div tag:

Next, we need to program our asp.net server side control to respond to
javascript client-side events. This would be done on the server side. For
example in C#:

Above we program our server control, MyServerControl1, to respond to the
client-side

onmouseover and onmouseout events. To the showimage function we pass strTitle
which is the text we want to display in the window. The info is displayed using
innerHTML attribute as described above.

Simulating Return Key

2006-11-09T00:45:00.000-08:00

Place this code on page load where buttonID is the ID of the button or image that you want to associate with the Form's return key. On pressing the return key the onclick event for the button is executed.

Page.RegisterHiddenField("__EVENTTARGET", buttonID);