ASP.NET WITH C# ERRORS TROUBLE SHOOTING

About Session ID in Asp.Net

2012-12-17T19:04:00.001+05:30

Session ID in ASP.Net

Session ID in ASP.Net | 1 comments

Asp.Net use 120 bit identifier to track each session. This is secure enough and can't be reverse engineered. When client communicate with server, only session id is transmitted, between them. When client request for data, ASP.NET looks on to session ID and retrieves corresponding data. This is done in following steps,

* Client hits web site and some information is stored in session.
* Server creates a unique session ID for that clients and stored in Session State Provider .
* Again client request For some information with that unique session ID from Server.
* Server,looks on Session Providers, and retrieve the serialized data from state server and type cast the object.

Difference between ViewBag, ViewDate and TempData in MVC

2012-12-17T18:56:00.002+05:30

ASP.NET MVC offers us three options ViewData, VieBag and TempData for passing data from controller to view and in next request. ViewData and ViewBag are almost similar and TempData performs additional responsibility. Lets discuss or get key points on those three objects:

Similarities between ViewBag & ViewData :

Helps to maintain data when you move from controller to view.
Used to pass data from controller to corresponding view.
Short life means value becomes null when redirection occurs. This is because their goal is to provide a way to communicate between controllers and views. It’s a communication mechanism within the server call.

Difference between ViewBag & ViewData:

ViewData is a dictionary of objects that is derived from ViewDataDictionary class and accessible using strings as keys.
ViewBag is a dynamic property that takes advantage of the new dynamic features in C# 4.0.
ViewData requires typecasting for complex data type and check for null values to avoid error.
ViewBag doesn’t require typecasting for complex data type.

ViewBag & ViewData Example:

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public ActionResult Index()
{
    ViewBag.Name = "Monjurul Habib";
    return View();
}

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public ActionResult Index()
{
    ViewData["Name"] = "Monjurul Habib";
    return View();
}

In View:

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@ViewBag.Name 
@ViewData["Name"]

TempData:

TempData is also a dictionary derived from TempDataDictionary class and stored in short lives session and it is a string key and object value. The difference is that the life cycle of the object. TempData keep the information for the time of an HTTP Request. This mean only from one page to another. This also work with a 302/303 redirection because it’s in the same HTTP Request. Helps to maintain data when you move from one controller to other controller or from one action to other action. In other words when you redirect, “Tempdata” helps to maintain data between those redirects. It internally uses session variables. Temp data use during the current and subsequent request only means it is use when you are sure that next request will be redirecting to next view. It requires typecasting for complex data type and check for null values to avoid error. generally used to store only one time messages like error messages, validation messages.

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public ActionResult Index()
{
  var model = new Review()
            {
                Body = "Start",
                Rating=5
            };
    TempData["ModelName"] = model;
    return RedirectToAction("About");
}
<pre><pre lang="cs">public ActionResult About()
{
    var model= TempData["ModelName"];
    return View(model);
}

The last mechanism is the Session which work like the ViewData, like a Dictionary that take a string for key and object for value. This one is stored into the client Cookie and can be used for a much more long time. It also need more verification to never have any confidential information. Regarding ViewData or ViewBag you should use it intelligently for application performance. Because each action goes through the whole life cycle of regular asp.net mvc request. You can use ViewData/ViewBag in your child action but be careful that you are not using it to populate the unrelated data which can pollute your controller

SQL Server Index Column Order - Does it Matter?

2012-12-17T18:35:00.001+05:30

Problem

There is a delicate balance on performance when it comes to setting up the indexes on a table. Too many indexes and your INSERT / UPDATE / DELETE performance will suffer, but not enough indexing will impact your SELECT performance. This tip will look at the order of the columns in your index and how this order impacts query plans and performance.

Solution

Sample SQL Server Table and Data Population

For this example we will setup two sample tables and populate each of the tables with data. Here is the code:

-- Table creation logic
CREATE TABLE [dbo].[TABLE1] 
([col1] [int] NOT NULL,[col2] [int] NULL,[col3] [int] NULL,[col4] [varchar](50) NULL)
GO
CREATE TABLE [dbo].[TABLE2] 
([col1] [int] NOT NULL,[col2] [int] NULL,[col3] [int] NULL,[col4] [varchar](50) NULL)
GO
ALTER TABLE dbo.TABLE1 ADD CONSTRAINT PK_TABLE1 PRIMARY KEY CLUSTERED (col1) 
GO
ALTER TABLE dbo.TABLE2 ADD CONSTRAINT PK_TABLE2 PRIMARY KEY CLUSTERED (col1)
GO
-- Populate tables
DECLARE @val INT
SELECT @val=1
WHILE @val < 1000
BEGIN  
   INSERT INTO dbo.Table1(col1, col2, col3, col4) VALUES(@val,@val,@val,'TEST')
   INSERT INTO dbo.Table2(col1, col2, col3, col4) VALUES(@val,@val,@val,'TEST')
   SELECT @val=@val+1
END
GO
-- Create multi-column index on table1
CREATE NONCLUSTERED INDEX IX_TABLE1_col2col3 ON dbo.TABLE1 (col2,col3)
  WITH (STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, 
        ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) 
  ON [PRIMARY]
GO

Before we run the following commands include the actual execution plan (Ctrl + M) and also turn on Statistics IO by running "SET STATISTICS IO ON" in the query window.

Single Table Query Example

For our first example let's take a look at a simple query with one column in the WHERE clause. The first query uses the second column (col3) of the index in the WHERE clause and the second query uses the first column (col2) of the index in the WHERE clause. Note we are using "DBCC DROPCLEANBUFFERS" to ensure the cache is empty before each query is executed. Here is the code:

DBCC DROPCLEANBUFFERS
GO
SELECT * FROM dbo.TABLE1 WHERE col3=88
GO
DBCC DROPCLEANBUFFERS
GO
SELECT * FROM dbo.TABLE1 WHERE col2=88
GO

Before running the command turn on the execution plan. Looking at the explain plans for these two queries we can see that the query that uses the second column (col3) of the index in the WHERE clause is performing an index scan on PK_TABLE1 and not even using the index we created on the column. The second query which has the first column (col2) of the index in the WHERE clause is performing a seek on the index we created and even on this small table uses fewer resources, 6 reads as compared to 4 reads, to execute this query. You can probably guess that this increase in performance only increases as the table becomes larger.

-- query 1
Table 'TABLE1'. Scan count 1, logical reads 6, physical reads 0
-- query 2
Table 'TABLE1'. Scan count 1, logical reads 4, physical reads 0

Two Table Join Query Example

For our next example let's take a look a query that has the same WHERE clause but also adds an inner join to another table. We will again have two queries. The first query has the second column (col3) of the index in the WHERE clause and the first column (col2) of the index is used to join the table. The second query has the first column (col2) of the index in the WHERE clause and second column (col3) of the index is used to join the table. Again we are using "DBCC DROPCLEANBUFFERS" to ensure the cache is empty before each query is executed. Here is the code:

DBCC DROPCLEANBUFFERS
GO
SELECT * 
  FROM dbo.TABLE1 INNER JOIN 
       dbo.TABLE2 ON dbo.TABLE1.col2 = dbo.TABLE2.col1
 WHERE dbo.TABLE1.col3=255       
GO
DBCC DROPCLEANBUFFERS
GO
SELECT * 
  FROM dbo.TABLE1 INNER JOIN 
       dbo.TABLE2 ON dbo.TABLE1.col3 = dbo.TABLE2.col1
 WHERE dbo.TABLE1.col2=255       
GO

Looking at the explain plans for these two queries we can see that when the column that the tables are joined on appears first in the index the query does an index scan of this table (as it did in the first example). The second query which has the first column of the index in the WHERE clause is performing a seek on the index we created. Again this second query uses fewer resources to complete, 6 reads as compared to the 8 reads required by the first query doing the scan. This increase in performance will also become greater as more data is added to these tables, as was the case in the previous example.

-- query 1
Table 'TABLE2'. Scan count 0, logical reads 2, physical reads 0
Table 'TABLE1'. Scan count 1, logical reads 6, physical reads 0

-- query 2
Table 'TABLE2'. Scan count 0, logical reads 2, physical reads 0
Table 'TABLE1'. Scan count 1, logical reads 4, physical reads 0

Summary

You can see from these simple examples above that the ordering of the columns in your index does have an impact on how any queries against the tables will behave. A best practice that I've followed that has been quite helpful when creating indexes is to make sure you are always working with the smallest result set possible. This means that your indexes should start with any columns in your WHERE clause followed by the columns in your JOIN condition. A couple more steps that also help query performance is to include any columns in an ORDER BY clause as well as making the index a covering index by including the columns in your SELECT list, this will remove the lookup step to retrieve data. One thing I mentioned earlier that I want to re-interate here is that by adding more indexes to tables as well as adding more columns to an existing index it will require more resources to update these indexes when inserting, updating and deleting data, so finding a balance is important.

Exception Handling in ASP.NET MVC

2012-12-17T17:50:00.001+05:30

Index

Introduction

Exception handling is a serious matter in any application, whether it's web or desktop. Implementing a proper exception handling is important in any application. In most cases once we catch the exception we have to log the exception details to database or text file and show a friendly message to the user.

In ASP.NET applications, error handling is done mostly in two ways: at local level using try-catch blocks and at global level using application events. ASP.NET MVC comes with some built-in support for exception handling throughexception filters. The HandleError is the default built-in exception filter. Unfortunately, the HandleError filter not gives a complete answer to the exception handling problem and that makes us to still rely on theApplication_Error event.

In this article, we will learn about the HandleError filter and discuss about the different exception handling mechanisms that will fit to an MVC application.

HandleErrorAttribute

Exception filters

The exception filters are attributes that can be applied over an action or a controller or even at a global level. When you apply the filter at the global level then it will handle the exceptions raised by all the actions of all the controllers. The exception filters not only catches the exceptions that are raised by the actions but also the ones that are raised by the action filters that are applied over that action.

All the exception filters implements the IExceptionFilter interface. The Listing 1. shows the definition of this interface. The IExceptionFilter contains a single method called OnException which will be called whenever an exception occurs. The ExceptionContext parameter which derives from ControllerContext provides access to controller, route data and HttpContext.

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public interface IExceptionFilter
{
    void OnException(ExceptionContext filterContext);
}

Listing 1. IExceptionFilter definition

The HandleErrorAttribute is the default implementation of the IExceptionFilter. When you create a MVC application you will see the HandleErrorAttribute is added to the GlobalFiltersCollection in theGlobal.asax.cs.

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public static void RegisterGlobalFilters(GlobalFiltersCollection filters)
{
    filters.Add(new HandleErrorAttribute());
}

Listing 2. Registering HandleErrorAttribute to GlobalFiltersCollection

What the HandleError filter does?

The HandleError filter handles the exceptions that are raised by the controller actions, filters and views, it returns a custom view named Error which is placed in the Shared folder. The HandleError filter works only if the<customErrors> section is turned on in web.config.

The HandleError filter handle exceptions only if the <customErrors> is turned on in web.config.

Error View

The Error view that is created by default contains the following HTML:

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@{
   Layout = null;
}

<!DOCTYPE html>
<html>
<head>
   <meta name="viewport" content="width=device-width" />
   <title>Error</title>
</head>
<body>
   <h2>
       Sorry, an error occurred while processing your request.
   </h2>
</body>
</html>

Listing 3. Error View

It contains nothing other than a simple text message. The Layout property is set to null so that the Error view doesn't inherits the application's style.

Accessing the exception details in Error view

In some cases, we have to access the exception information from the Error view. The HandleError filter not only just returns the Error view but it also creates and passes the HandleErrorInfo model to the view. TheHandleErrorInfo model contains the details about the exception and the names of the controller and action that caused the exception.

Here is the definition of the HandleErrorInfo.

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public class HandleErrorInfo
{   
    public HandleErrorInfo(Exception exception, string controllerName, 
        string actionName);

    public string ActionName { get; }

    public string ControllerName { get; }

    public Exception Exception { get; }
}

Listing 4. HandleErrorInfo model

Though it's not necessary, let's strongly type the Error view to the HandleErrorInfo model.

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@model System.Web.Mvc.HandleErrorInfo

Listing 5. Strongly typing Error view to HandleErrorInfo model

We can easily show the exception and other information by accessing the model through the Model property.

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<h2>Exception details</h2>
<p>
    Controller: @Model.ControllerName <br>
    Action: @Model.ActionName
    Exception: @Model.Exception
</p>

Listing 6. Displaying exception details in Error view

Returning different views for different exceptions

We can return different views from the HandleError filter. For ex. if you want to return one view for database exceptions and another view for application exceptions, you could easily do that by specifying the View andException properties as shown in the below listing.

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[HandleError(Exception = typeof(DbException), View = "DatabaseError")]
[HandleError(Exception = typeof(AppException), View = "ApplicationError")]
public class ProductController
{
    
}

Listing 7. Setting View and Exception properties

The HandleErrorAttribute can be applied multiple times over a controller or action or at global level.

Limitations of HandleError

The HandleError filter has some limitations by the way.

Not support to log the exceptions
Doesn't catch HTTP exceptions other than 500
Doesn't catch exceptions that are raised outside controllers
Return error view even for exceptions occurred in AJAX calls

Let us see one by one!

1. Not support to log the exceptions

Logging is very important in error handling and even simple applications get much benefit by logging the errors to a text file or database. The HandleError filter suppresses the exceptions once they are handled and all it does is showing a custom view to the user.

2. Doesn't catch HTTP exceptions other than 500.

The HandleError filter captures only the HTTP exceptions having status code 500 and by-passes the others. Let's assume we have an action that returns all the posts published for a particular category. If the category not exists then we are throwing a 404 HTTP exception.

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public ViewResult Posts(string category)
{
    if(_blogRepository.Category(category) == null)
        throw new HttpException(404, "Category not found");

    return _blogRepository.Posts(category);
}

Listing 8. Throwing HttpException from action

If any user passes an invalid category a 404 exception will be thrown from the action and the HandleError don't catch this error. Usually in this case, programmers like to show a custom view with a message "The requested category is not found or invalid". Not only the 404 exceptions, the HandleError doesn't catch any HTTP exception other than 500.

Handling the HTTP exceptions in filters is right or wrong is a thing for debate. In some cases we may have to bypass the HTTP exceptions to the framework to take proper action against it. So handling HTTP exceptions in filters depends upon the application and it's not mandatory!

3. Doesn't catch exceptions that are raised outside controllers

The HandleError is an exception filter and exception filters are called only if any exception happens inside the action or in the action filters that are applied over the action. So if the exception happens some other place the filter will be silent.

For example, say we have set up a route constraint for a specific route as shown in the below listing.

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routes.MapRoute(
	 "Default", 
	 "Strange~Action",
	 new { controller = "NonIE", action = "Action"  },
	 new { browserConstraint = new UserAgentConstraint("IE") } 
);

Listing 9. Adding constraints to routes

Route Constraints restricts the set of URLs that a route will match against.

The UserAgentConstraint that we set up in the above route restricts the route to handle requests from only Internet Explorer browsers. In the implementation of UserAgentConstraint I'm purposely throwing an exception.

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public class UserAgentConstraint : IRouteConstraint
{
	private readonly string _restrictAgent;

	public UserAgentConstraint(string restrictAgent)
	{
		_restrictAgent = restrictAgent;
	}

	public bool Match(HttpContextBase httpContext, Route route, string parameterName, RouteValueDictionary values, RouteDirection routeDirection)
	{
	        // TODO: return true if the browser is not restricted one.
		throw new NotImplementedException("You forget to implement me");
	}
}

Listing 9. UserAgentConstraint

This exception is thrown at very early stage and HandleError filter won't be there to catch this. When we access the route where the above constraint is applied we will see the yellow screen instead of the custom error page.

4. Return error view even in exceptions occurred in AJAX calls.

In case of AJAX calls, if some exception happens the HandleError filter returns the custom error view, which is not useful in the client-side. It would be great to return a piece of JSON in AJAX exceptions and for that we have to extend the HandleError filter or have to create a custom exception filter.

HandleError vs. Application_Error

Exception filters are not global error handlers and this is an important reason that forces us to still rely onApplication_Error event. Some programmers don't even use the HandleError filter in their application at all and use only the Application_Error event for doing all the error handling and logging work. The important problem we face in the Application_Error event is, once the program execution reaches this point then we are out of MVC and we can't access the context objects and other useful stuff of the framework.

Another important feature that exception filters brings to us is we can handle the exceptions in different ways at different scopes, this is important in some cases, for ex. when exceptions are raised from one controller we have to return a custom error view and for other controllers we have to return a different error view, this could be easily accomplished through exception filters but not easily through the Application_Error event.

The bottom-line is, we need to use the Application_Error event at most of the cases in applications unless we are using a framework like ELMAH which magically handles all the exceptions. But whether we need to use theHandleError filter or not is totally depend upon the application. When we need a controller or action level exception handling then we can use the HandleError filter along with the Application_Error event, else we can simply ignore the HandleError filter.

Extending HandleError

Most of the cases we have to extend the built-in HandleError filter or have to create a custom exception filter to do some useful job like logging. Here is an example that shows how to extend the built-in filter to log the exceptions using log4net and return a JSON object for AJAX calls.

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public class CustomHandleErrorAttribute : HandleErrorAttribute
{
    private readonly ILog _logger;

    public CustomHandleErrorAttribute()
    {
        _logger = LogManager.GetLogger("MyLogger");
    }

    public override void OnException(ExceptionContext filterContext)
    {
        if (filterContext.ExceptionHandled || !filterContext.HttpContext.IsCustomErrorEnabled)
        {
            return;
        }

        if (new HttpException(null, filterContext.Exception).GetHttpCode() != 500)
        {
            return;
        }

        if (!ExceptionType.IsInstanceOfType(filterContext.Exception))
        {
            return;
        }

        // if the request is AJAX return JSON else view.
        if (filterContext.HttpContext.Request.Headers["X-Requested-With"] == "XMLHttpRequest")
        {
            filterContext.Result = new JsonResult 
            { 
                JsonRequestBehavior = JsonRequestBehavior.AllowGet, 
                Data = new 
                { 
                    error = true,
                    message = filterContext.Exception.Message
                } 
            };
        }
        else
        {
            var controllerName = (string)filterContext.RouteData.Values["controller"];
            var actionName = (string)filterContext.RouteData.Values["action"];
            var model = new HandleErrorInfo(filterContext.Exception, controllerName, actionName);
            
            filterContext.Result = new ViewResult
            {
                ViewName = View,
                MasterName = Master,
                ViewData = new ViewDataDictionary<HandleErrorInfo>(model),
                TempData = filterContext.Controller.TempData
            };
        }

        // log the error using log4net.
        _logger.Error(filterContext.Exception.Message, filterContext.Exception);

        filterContext.ExceptionHandled = true;
        filterContext.HttpContext.Response.Clear();
        filterContext.HttpContext.Response.StatusCode = 500;

        filterContext.HttpContext.Response.TrySkipIisCustomErrors = true;      
    }
}

Listing 10. Extending HandleError

Most of the code are same as in the built-in filter. Notice we have ignored the HTTP exceptions so anyway we need to wire-up the Application_Error event to catch and log the missed exceptions. If the request is an AJAX call then we are returning a JSON object that contains a boolean and the exception message else we are returning the error view. We are setting the response status code as 500 and the HandleError filter also does the same, this is important in terms of REST and HTTP standards.

Returning views from Application_Error

In some applications we have to depend upon the Application_Error event for handling all the exceptions or the ones that are missed by the exception filters. Mostly programmers like to return an MVC view instead of a static page. Though we are out of the MVC context still we can return a view using a controller (thanks to StackOverflow).

Let's create an Error controller that return different views for different errors as shown in the below listing.

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public class ErrorController : Controller
{
    public ActionResult Index()
    {
        return View();
    }

    public ActionResult NotFound()
    {
        return View();
    }
}

Listing 11. Error Controller

We have to invoke this Error controller from the Application_Error to return a view after the exception is logged.

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protected void Application_Error(object sender, EventArgs e)
{
    var httpContext = ((MvcApplication)sender).Context;
    
    var currentRouteData = RouteTable.Routes.GetRouteData(new HttpContextWrapper(httpContext));    
    var currentController = " ";
    var currentAction = " ";
    
    if(currentRouteData != null)
    {
        if(currentRouteData.Values["controller"] != null && !String.IsNullOrEmpty(currentRouteData.Values["controller"].ToString()))
        {
            currentController = currentRouteData.Values["controller"].ToString();
        }
        
        if(currentRouteData.Values["action"] != null && !String.IsNullOrEmpty(currentRouteData.Values["action"].ToString()))
        {
            currentAction = currentRouteData.Values["action"].ToString();
        }
    }
    
    var ex = Server.GetLastError();

    var controller = new ErrorController();
    var routeData = new RouteData();
    var action = "Index";

    if (ex is HttpException)
    {
        var httpEx = ex as HttpException;

        switch (httpEx.GetHttpCode())
        {
            case 404:
                action = "NotFound";
                break;

            // others if any

            default:
                action = "Index";
                break;
        }
    }

    httpContext.ClearError();
    httpContext.Response.Clear();
    httpContext.Response.StatusCode = ex is HttpException ? ((HttpException)ex).GetHttpCode() : 500;
    httpContext.Response.TrySkipIisCustomErrors = true;
    routeData.Values["controller"] = "Error";
    routeData.Values["action"] = action;

    controller.ViewData.Model = new HandleErrorInfo(ex, currentController, currentAction);    
    ((IController)controller).Execute(new RequestContext(new HttpContextWrapper(httpContext), routeData));
}

Listing 12. Returning views from Application_Error

We are doing many things in the above code, mainly we are instantiating the Error controller and invoking it by calling the Execute() method passing the HandleErrorInfo model and this is the model used by theHandleError filter as well.

We are using a switch statement just to demonstrate how we can return different error views for different HTTP exceptions. If you want to take care of AJAX calls you have to change the implementation little as we did in the custom HandleError filter but to keep things simple I've ignored that part.

ELMAH

ELMAH (Error Logging Modules and Handlers) is an application-wide error logging facility that is completely pluggable. You can easily configure ELMAH for an ASP.NET MVC application without much code. The other benefits brought up by ELMAH is, it provides a custom page where the admin can view the errors including the original yellow screen, also it provides options to send emails, generate RSS etc.

ELMAH logs only unhandled exceptions so we have to signal ELMAH to log the exceptions that are handled. When we use the HandleError filter and ELMAH in an application we will confused seeing no exceptions are logged by ELMAH, it's because once the exceptions are handled by the HandleError filter it sets the ExceptionHandledproperty of the ExceptionContext object to true and that hides the errors from logged by ELMAH. A better way to overcome this problem is extend the HandleError filter and signal to ELMAH as shown in the below listing.

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public class ElmahHandleErrorAttribute : HandleErrorAttribute
{
    public override void OnException(ExceptionContext filterContext)
    {
        base.OnException(filterContext);

        // signal ELMAH to log the exception
        if (filterContext.ExceptionHandled)
            ErrorSignal.FromCurrentContext().Raise(filterContext.Exception);
    }
}

Listing 13. Signaling to Elmah

Summary

In this article we saw about the built-in HandleError filter available with ASP.NET MVC to handle the exceptions. The HandleError filter has some limitations and most importantly it doesn't handle all the exceptions that are raised by the application.

Although HandleError filter bring some benefits in customizing error handling at a controller or action level still we have to rely on the Application_Error event.

ELMAH is an error handling module that is easily pluggable to an ASP.NET application. Unlike HandleError, ELMAH catches all the exceptions raised by the application.

Appication Life Cycle of Asp.Net

2012-12-07T18:33:00.000+05:30

All Joins in Sql Server

2012-12-07T18:30:00.002+05:30

FileUpload control working on second click but not at first click?

2012-11-27T15:33:00.001+05:30

Change your master page form tag as like this

<form id="form1" enctype="multipart/form-data" runat="server">

FileUpload control not Working in UpdatePanel asp.net

2012-11-27T15:31:00.000+05:30

Add this code in UpdatePanel
<Triggers>
<asp:PostBackTrigger ControlID="btnSubmit" />
</Triggers>

Difference between HTTP handlers and HTTP modules

2012-11-06T17:38:00.001+05:30

HTTP handlers are the end point objects in ASP.NET pipeline and an HTTP Handler essentially processes the request and produces the response. For example an ASP.NET Page is an HTTP Handler.

HTTP Modules are objects which also participate the pipeline but they work before and after the HTTP Handler does its job and produce additional services within the pipeline (for example associating session within a request before HTTP handler executes, and saving the session state after HTTP handler has done its job, is basically done by an HTTP module, SessionStateModule)

Dynamically changing master in ASP.NET , C#

2012-11-06T16:39:00.000+05:30

protected void Page_PreInit(object seder, EventArgs e)
{
this.MasterPageFile = "~/MasterPage.master";
}

Ajax ComboBox Validation in JavaScript

2012-08-24T14:53:00.002+05:30

var cmb = document.getElementById('<%=cmbwno.ClientID %>');
var string = cmb.control._originalSelectedIndex;
if (string == 0) {
alert("Select Worker Number");
document.getElementById('<%=cmbwno.ClientID %>').focus();
return false;
}

but Here combobox must be auto postback true

Simple Email validation in Javascript

2012-08-22T23:02:00.002+05:30

function is_email(email) {
var emailReg = /^[a-zA-Z0-9._-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,4}$/;
return emailReg.test(email);
}

Display Row Number or SNO for Gridview Asp.Net

2012-08-22T12:35:00.003+05:30

<asp:TemplateField HeaderText="S.NO.">
<ItemTemplate>
<asp:Label ID="Label1" runat="server" Text='<%# Container.DataItemIndex + 1 %> '>
</asp:Label>
</ItemTemplate>
</asp:TemplateField>

Get selected text of dropdownlist in Javascript

2012-08-21T22:54:00.000+05:30

ddlTime.options[ddlTime.selectedIndex].innerHTML

Send mail from gmail C# Asp.Net

2012-08-19T20:37:00.001+05:30

MailMessage mail = new MailMessage();
mail.To.Add(txtUM.Text);
mail.From = new MailAddress("pavan.it30@gmail.com");
mail.Subject = "Welcome To NL SOFTTECH SERVICES!!";
string Body = "User ID :"+txtUI.Text+" Password :"+txtPass.Text;
mail.Body = Body;
mail.IsBodyHtml = true;

//mail.Attachments.Add(
SmtpClient smtp = new SmtpClient();
smtp.Host = ConfigurationManager.AppSettings["SMTP"];
smtp.Credentials = new System.Net.NetworkCredential(ConfigurationManager.AppSettings["FROMEMAIL"], ConfigurationManager.AppSettings["FROMPWD"]);
smtp.EnableSsl = true;
smtp.Send(mail);
Label1.Text = "Mail Sent Successfully";

and add this tag in web.config

<appSettings>

</appSettings>

Send mail Code C# Asp.Net

2012-08-19T20:34:00.002+05:30

SmtpClient smtpClient = new SmtpClient();
System.Net.Mail.MailMessage message = new System.Net.Mail.MailMessage();
try
{
MailAddress fromAddress = new MailAddress("charan@citycinemas.in", "CityCinemas");
smtpClient.Host = "202.0.103.18";
smtpClient.Port = 25;
message.From = fromAddress;
message.To.Add("pavan.it30@gmail.com");
message.Subject = "Ticket Details";

//message.CC.Add("anil.vnkta@gmail.com");
// message.CC.Add("");

// You can specify Address directly as string
// message.Bcc.Add(new MailAddress(""));
//message.Bcc.Add(new MailAddress(""));
message.IsBodyHtml = true;
message.Body = MailBody;
smtpClient.Send(message);
}
catch (Exception ex)
{

}

Read GriedView from javascript (Template feild like TextBox,Image,Buttom..etc)

2012-08-18T23:01:00.000+05:30

Delete all directory cookies in javascript

2012-08-18T22:56:00.001+05:30

var name = "loginstatus";
var pathBits = location.pathname.split('/');
var pathCurrent = ' path=';

// do a simple pathless delete first.
document.cookie = name + '=; expires=Thu, 01-Jan-70 00:00:01 GMT; path=/; domain = www.citycinemas.in;';

for (var i = 0; i < pathBits.length; i++) {
pathCurrent += ((pathCurrent.substr(-1) != '/') ? '/' : '') + pathBits[i];
document.cookie = name + '=; expires=Thu, 01-Jan-70 00:00:01 GMT;' + pathCurrent + ';';
}

Cookie for all directories in javascript

2012-08-18T22:52:00.002+05:30

var loginst = "loginstatus";
var value="vvv";
document.cookie = loginst + "=" + value+";path=/;";

Load a page to Parent Page IFRAME in javascript

2012-08-18T22:25:00.000+05:30

parent.window.frames['fr1'].location = 'PrintTicket.aspx';

dynamically load a page to IFRAME in javascript

2012-08-18T22:23:00.002+05:30

$("#frameDiv").html("<iframe src='user/BookByMovie.aspx' id='fr1' width='100%' name='fr1' /></iframe>");

Set Auto height to iframe in javascript

2012-08-18T22:19:00.005+05:30

script type='text/javascript'>

function setIframeHeight( iframeId ) /** IMPORTANT: All framed documents *must* have a DOCTYPE applied **/
{
 var ifDoc, ifRef = document.getElementById( iframeId );

 try
 {   
  ifDoc = ifRef.contentWindow.document.documentElement;  
 }
 catch( e )
 { 
  try
  { 
   ifDoc = ifRef.contentDocument.documentElement;  
  }
  catch(ee)
  {   
  }  
 }
 
 if( ifDoc )
 {
  ifRef.height = 1;  
  ifRef.height = ifDoc.scrollHeight;
  
  /* For width resize, enable below.  */
  
  // ifRef.width = 1;
  // ifRef.width = ifDoc.scrollWidth; 
 }
}

</script>

<iframe id = "myIframe"  onload = "setIframeHeight( this.id )">

double or float convert to currency format C#

2012-08-17T16:43:00.000+05:30

double amount=1234;

amount.ToString("#,##0.00");

Then resulting string is 1,234.00

Call a URL and save the response C# ASP.NET

2012-08-17T15:28:00.003+05:30

string url = "http://69.50.198.112/send.php?usr=24129&pwd=123456&ph=9030102460&text=fromApp";

WebRequest request = HttpWebRequest.Create(url);

WebResponse response = request.GetResponse();

StreamReader reader = new StreamReader(response.GetResponseStream());

string urlText = reader.ReadToEnd();

Run application Shortcut from Command Prompt or batch file

2012-08-13T20:40:00.003+05:30

Start Call "C:\Program Files (x86)\TECHNOARCHIVE\MailCityCinemas\CityCinemas.exe"

OR

start "" "C:\Program Files (x86)\TECHNOARCHIVE\MailCityCinemas\CityCinemas.exe"