Asp.Net Interview Questions

Fiserv Interview Questions.

2009-11-07T03:43:00.001-08:00

1) For edit functionality in DataGird specify Column name
2) Why you may not want to use Paging funtionality in data grid
3) Function of SqlCommanBuilder in code.
4) Find the error in code . Its related to database connection. I think that connection sould be closed in finally instead of try.
5) What is the relation between src='' & Inherits='' in <@ Page > directive
6) What is derective in the user control page & its extention of file
7) Question related to 404 error code Error page & Default error page.
8) Its related to Autherization in web config related to folders
9) Related to definition
10) not remembred with question but answer is cookiless = true related question
11) Page is posting the 2 times why is it so 1) user control load 2) some control call load
12) describe !Page.PostBack Select Options
13) Question related to Session mode = SQLServer
14) Some question related to validation control - compare validator
15) Some question related to page inheritance - I think answer is - page
16) One question related to Asp.net 1.1 -- Is the mobile application will work in asp.net 1.1
17) question related to ASP.NET AdRotator Control - what is tag - A number that indicates the importance of the ad in the schedule of rotation relative to the other ads in the file (optional).

The larger the number, the more often the ad is displayed. The total of all Impressions values in the XML file cannot exceed 2,047,999,999. If it does, the AdRotator throws a run-time exception.

dont send me reply

18) Some question related to - error related to - input id="Button1" onserverclick="check" runat="server" type="button" value="button" /> & onserverclick

19) In repeter control they want to show title -- <%#Container.DataItem("title")%> OR <%# DataBinder.Eval(Container.DataItem,"CustomerName") %> Or ...
20) Related to DataList -- Value & Text Showing Its simple.
21) when the Viewsate is avilable in life cycle - answer is after LOAD
22) Simple c# code answer is 1
23) What are the Session-State Modes ? ans - InPro,StateServer,SQLServer
24)

Send Email in asp.net

2009-10-05T09:51:00.000-07:00

add System.Net.Mail; namespace
///*********************************************************************************
///

///To Send the simple Email
///

    ///
From Email Id
    /// To Email Id
    /// Email Subject
    /// Email Body
    /// Returns bool with Indication
    ///*********************************************************************************
    public bool SendEMail(string FromAddressId, string ToAddressId,
                          string Subject, string MessageBody)
    {
        SmtpClient objSmtpClient = new SmtpClient();
        MailMessage message = new MailMessage();

        try
        {
            MailAddress fromAddress = new MailAddress(FromAddressId);
            objSmtpClient.Host = SmtpServerName;
            objSmtpClient.Port = SmtpServerPortNo;
            message.From = fromAddress;
            message.To.Add(ToAddressId);
            message.Subject = Subject;
            message.IsBodyHtml = true;
            message.Body = MessageBody;
            objSmtpClient.Send(message);
            return true;
        }
        catch (Exception ex)
        {
            throw ex;
        }
        finally
        {
            objSmtpClient = null;
            message = null;
        }
    } // End Of Sendmail Function

Creating Error log

2009-10-05T09:42:00.000-07:00

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;
using CommonComponents;
using System.IO;

///

/// Summary description for clsErrorLog
///

public class clsErrorLog
{
    /*************************************************************
    NAME:          WriteToErrorLog
    PURPOSE:       Open or create an error log and submit error message
    PARAMETERS:    ex - object of Exception class
                   ErrorTitle - title of the error
                   ErrorClass - name of form or class in which error occured
                   ErrorMethod - name of the method in which error occured
    RETURNS:       Nothing
    '*************************************************************/
    ///

/// Open or create an error log and submit error message. Returns void
///

    ///
object of Exception class
    /// title of the error
    /// name of form or class in which error occured
    /// name of the method in which error occured
    ///
    public static void WriteToErrorLog(Exception ex, string ErrorTitle, string ErrorClass, string ErrorMethod)
    {
        /* check and make the directory if necessary; this is set to look in
           the application folder, you may wish to place the error log in
           another location depending upon the user's role and write access to
           different areas of the file system */
        string strPath = HttpContext.Current.Server.MapPath("~\\Errors");
        //if (!Directory.Exists(strPath))
        //    Directory.CreateDirectory(strPath);
        DirectoryInfo objDirInfor = new DirectoryInfo(strPath);
        if (!objDirInfor.Exists)
            objDirInfor.Create();
        //check the file
        FileStream fs = new FileStream(strPath + "\\MilesSelfTestWebErrorlog.txt", FileMode.OpenOrCreate, FileAccess.ReadWrite);
        StreamWriter s = new StreamWriter(fs);
        s.Close();
        fs.Close();
        //log it
        FileStream fs1 = new FileStream(strPath + "\\MilesSelfTestWebErrorlog.txt", FileMode.Append, FileAccess.Write);
        StreamWriter s1 = new StreamWriter(fs1);
        System.Text.StringBuilder strErrorDesc = new System.Text.StringBuilder("");
        strErrorDesc.AppendLine("Title: " + ErrorTitle + Environment.NewLine);
        strErrorDesc.AppendLine("ErrorClass: " + ErrorClass + Environment.NewLine);
        strErrorDesc.AppendLine("ErrorMethod: " + ErrorMethod + Environment.NewLine);
        strErrorDesc.AppendLine("Message: " + ex.Message + Environment.NewLine);
        strErrorDesc.AppendLine("StackTrace: " + ex.StackTrace + Environment.NewLine);
        strErrorDesc.AppendLine("Date/Time: " + DateTime.Now.ToString() + Environment.NewLine);
        strErrorDesc.AppendLine("================================================" + Environment.NewLine);
        s1.Write(strErrorDesc.ToString());
        s1.Close();
        fs1.Close();
        //clsEmail objSimpleEmail = new clsEmail();
        //objSimpleEmail.SendEMail("admin@nigeriaexamsonline.com", "bhaveshp@iprogrammer.co.in, milindm@iprogrammer.co.in", ErrorTitle, strErrorDesc.ToString());
        //objSimpleEmail = null;
    }
}

Finding Nth Highest Salary Query

2009-09-16T00:17:00.000-07:00

SELECT max(sal) FROM tbltemp WHERE sal NOT IN
(SELECT distinct top 2 sal FROM tbltemp ORDER BY sal desc)

for eg. for 3rd highest top will be 3-1 =2 (top 2) therefore top N-1

Adding Custom Tags in Web.config

2009-09-14T00:31:00.000-07:00

To add cutom tag in your web config its a simple process. I will expain it step by step

Add Following to your web config

Remember you have to add information about your System assembly which you can find in your GAC (Global assembly cache) Path: "C:\WINDOWS\assembly" right click on System assembly and you will get Property about it.

Then to get those custom tag values write the following code on default.aspx.cs file

protected void Page_Load(object sender, EventArgs e)
{
NameValueCollection Col = new NameValueCollection();
Col = (NameValueCollection)System.Configuration.ConfigurationManager.GetSection("MyCustomSection");
        for (int i = 0; i < c1.Keys.Count; i++)
        {
           Response.Write(String.Format("Key = {0}, Value = {1} ", c1.Keys[i], c1[i].ToString()));
        }
}

Singleton Design Pattern

2009-09-09T19:39:00.000-07:00

one of the good explanation found in ASP.NET 3.5 Application Architecture Design

public sealed class EmailManager

{

private static EmailManager _manager;

//Private constructor so that objects cannot be created

private EmailManager()

{

}

public static EmailManager GetInstance()

{

// Use 'Lazy initialization'

if (_manager == null)

{

//ensure thread safety using locks

lock(typeof(EmailManager)

{

_manager = new EmailManager();

}

return _manager;

}

let us understand the code step-by-step:

1. public sealed class EmailManager: We have used the sealed keyword to make our EmailManager class uninheritable. This is not necessary, but there is no use having derived classes as there can be only one instance of this class in memory. Having derived class objects will let us create two or more instances which will be against the singleton's design objective.

2. private static EmailManager _manager:Next, we create a variable named _manager, which holds a reference to the single instance of our EmailManager class. We have used a static modifier because we will be accessing this variable from a static method—GetEmailManager(), and static methods can use only static variables.
private EmailManager()
{
}
We need to create a private constructor to make sure that we don't accidentally initialize an object of the GetEmailManager class. By only initializing via the static GetInstance() method, we should get a single instance of this class.
3. public static EmailManager GetInstance()
{
// Use 'Lazy initialization'
if (_manager == null)
{
//ensure thread safety using locks
lock(typeof(EmailManager)
{
_manager = new EmailManager();
}
}
return _manager;
}
GetInstance() is the static method that we will use from outside this code to get the current reference of the EmailManager class. In this method, we are using the lazy loading technique to load the instance on demand. We first check if the current instance is null or not. If it is null, then we create a new one; otherwise we return the existing
static instance.
lock(typeof(EmailManager)

4. The private _manager object, marked static, is used inside a critical section (using lock) to make sure it is thread safe. Thread safety is very important here. Otherwise, two threads might simultaneously call GetInstance() and, on finding the EmailManager instance (_manager) null, will both try to create an instance, thereby creating two instances of the class. The lock keyword helps us make sure that once a thread enters the region, no other thread can do so until the first thread exits, making our code thread safe. We pass the EmailManager's type in order to lock the statement using the typeof operator to define the scope of the lock statement.
An important point to note is that in the above code we have to make sure that the
type used in the typeof() command is not publicly accessible, otherwise the scope
would be affected. It is better to create a private object within our class to use as a
reference object in the lock statement, as in:
private static object forLock = new object();
public static EmailManager GetInstance()
{
// Use 'Lazy initialization'
if (_manager == null)
{
//ensure thread safety using locks
lock(typeof(forLock)
{
_manager = new EmailManager();
}
}
return _manager;
}
So the above code can be used for implementing a Singleton design pattern in

ASP.NET effectively and safely.

SOAP Header (credentials) for cosuming web service

2009-09-07T03:12:00.000-07:00

Its the optional part of SOAP Message. Instead including meta data (Credentials) in your web signature you can use SOAP header to consume web service.

// SOAP Header class

public class HelloHeader : SoapHeader
{
    public string Username;
    public string Password;
}

    public HelloHeader myHeader;
    [WebMethod]
    [SoapHeader("myHeader")]
    public string HelloWorld()
    {
        if (myHeader == null)
        {
            return "Hello World";
        }
        else
        {
            return "Hello " + myHeader.Username + ". " +
            "
Your password is: " + myHeader.Password;
        }
    }

// Consuming this web service
localhost.HelloHeader objHEader = new WindowsApplication1.localhost.HelloHeader();
localhost.HelloSoapHeader objService = new WindowsApplication1.localhost.HelloSoapHeader();
objHEader.Username = "milind";
objHEader.Password = "mahajan";
objService.HelloHeaderValue = objHEader;
MessageBox.Show( objService.HelloWorld());

Metod overloading in web serive

2009-09-07T02:52:00.000-07:00

To overload web methods you have to use MessageName attribute otherwise you will get error.

[WebMethod(MessageName = "Hello")]
public string Hello()
{
return "Hello";
}

[WebMethod(MessageName = "HelloWithFirstName")]
public string Hello(string FirstName)
{
return "Hello " + FirstName;
}

Web serice to upload image on server

2009-09-07T02:29:00.001-07:00

/// web service
/// Upload image on server with the .jpg, .ico, .gif, .bmp, .png formats.
/// Size should be less than 80kb
///
/// /// ///
[WebMethod]
public string UploadImage(byte[] ImgIn, string FileName)
{
MemoryStream ms = null;
Bitmap b = null;
try
{
ms = new MemoryStream(ImgIn);
if (ms.Length <= 80000) // 80kb limit for image to upload
{
b = (Bitmap)Image.FromStream(ms);
if (FileName.ToLower().Contains(".jpeg") || FileName.ToLower().Contains(".jpg"))
b.Save("C:\\" + FileName, System.Drawing.Imaging.ImageFormat.Jpeg);
if (FileName.ToLower().Contains(".gif"))
b.Save("C:\\" + FileName, System.Drawing.Imaging.ImageFormat.Gif);
if (FileName.ToLower().Contains(".bmp"))
b.Save("C:\\" + FileName, System.Drawing.Imaging.ImageFormat.Bmp);
if (FileName.ToLower().Contains(".png"))
b.Save("C:\\" + FileName, System.Drawing.Imaging.ImageFormat.Png);
if (FileName.ToLower().Contains(".ico"))
b.Save("C:\\" + FileName, System.Drawing.Imaging.ImageFormat.Icon);
return "Uploaded successfully.";
}
else
return "Image size should be less than 80kb.";
}
catch (Exception ex)
{
return "Some error occurred, please try again later.";
}
finally
{
if (ms != null)
ms.Dispose();
if (b != null)
b.Dispose();
}
}

// Consuming the web service

localhost.ImageUpload obj = new localhost.ImageUpload();
FileStream fs = new FileStream(FileUpload1.PostedFile.FileName, FileMode.OpenOrCreate, FileAccess.Read);
Byte[] img = new Byte[fs.Length];
fs.Read(img, 0, Convert.ToInt32(fs.Length));
lblMsg.Text = obj.UploadImage(img, FileUpload1.FileName);

Nullable in c#

2009-09-02T05:04:00.000-07:00

Nullable types can represent all the values of an underlying type, and an additional null value. Nullable types are declared in one of two ways:
        System.Nullable variable
        -or-
        T? variable
Any value type may be used as the basis for a nullable type

class Program
    {
        static void Main(string[] args)
        {
            int? x = 10;
            if (x.HasValue)
            {
                System.Console.WriteLine(x.Value);
            }
            else
            {
                System.Console.WriteLine("Undefined");
            }

            Console.ReadKey();

            int? y = null;
            if (y != null)
            {
                System.Console.WriteLine(y.Value);
            }
            else
            {
                System.Console.WriteLine("Undefined");
            }

            Console.ReadKey();

            int? n = 5;

            //int m1 = n;      // Will not compile.
            int m2 = (int)n;   // Compiles, but will create an exception if n is null.
            int m3 = n.Value; // Compiles, but will create an exception if n is null.

            Console.ReadKey();
            int A = 0;
            System.Console.WriteLine("A++ = {0}", A++);
            A = A + 1;
            System.Console.WriteLine("A = A + 1 {0}", A);
            System.Console.WriteLine("++A {0}", ++A);
            Console.ReadKey();

        }
    }

Explicit keyword in c#

2009-09-02T04:58:00.001-07:00

The explicit keyword is used to declare an explicit user-defined type conversion operator

class Celsius
    {
        public Celsius(float temp)
        {
            degrees = temp;
        }
// define explicit Celsius-to-Fahrenheit conversion operator:
        public static explicit operator Fahrenheit(Celsius c)
        {
            return new Fahrenheit((9.0f / 5.0f) * c.degrees + 32);
        }
        public float Degrees
        {
            get { return degrees; }
        }
        private float degrees;
    }

    class Fahrenheit
    {
        public Fahrenheit(float temp)
        {
            degrees = temp;
        }
// define explicit Fahrenheit-to-Celsius conversion operator:
        public static explicit operator Celsius(Fahrenheit f)
        {
            return new Celsius((5.0f / 9.0f) * (f.degrees - 32));
        }
        public float Degrees
        {
            get { return degrees; }
        }
        private float degrees;
    }

static void Main(string[] args)
        {
                Fahrenheit f = new Fahrenheit(100.0f);
                Console.Write("{0} fahrenheit", f.Degrees);
                Celsius c = (Celsius)f;// explicit conversion
                Console.Write(" = {0} celsius", c.Degrees);
                Fahrenheit f2 = (Fahrenheit)c;// explicit conversion
                Console.WriteLine(" = {0} fahrenheit", f2.Degrees);
        }

Cursor in sql server

2009-09-01T06:43:00.000-07:00

-To fetch row by row data

Declare Cursor
Open
Fetch first time
fetch data until @@Fetch_Status = 0
Close
Deallocate

Disadvantage:
- Time Consuming
- required lot of resources & temporary storage.

View in sql server

2009-09-01T06:37:00.000-07:00

Referred as "Virtual Table"
Can not store data (except for indexed views) rather than only referto data present in table.

e.g. Create View vwsample
[optional]
With Encryption OR
With Schemabinding
[/optional]
AS

Select Cid, CName FRom Customer

GO

With Encryption - You can see view query (its encrypted)
With Schemabinding - You are not able to alter table on which it's created.

Assembly in .net

2009-09-01T06:18:00.000-07:00

-It is the fundamental building block of .net framework
-basic unit of deployment or versioning (.exe or .dll)
-Consisting

Manifest
Metadata
IL Code
Resources

1) Manifest- Describe assembly itself

Contents

Assembly Name
Version number
Culture
Strong name information
List of files
Type reference information
Information on reference assemblies

2) Metdata- Describe Contents within assembly like Classes, Namespaces, Interfaces, Scope, Properties, Methods & their parameteres.

3) IL Code- The compilers translates your code into Microsoft intermediate language (MSIL). The common language runtime includes a JIT compiler for converting this MSIL then to native code.

4) Resources- are the files like image files

WCF introduction

2009-09-01T06:06:00.000-07:00

-Code name is "Indigo"
-Is a Programming framework used to build application that intercommunicate
-Unification technology which unify
1) .Net remoting
2) MSMQ (Microsoft Message Quenning)
3) Web service
4) COM+
into single common, general service-oriented programming model for communication.
-Wcf design according to SOA (service oriented architecture)

Advantage:

1) Unification of existing technologies.
2) Interoperability across platform.
3) Service Oriented development.
4) more flexible than standard web service.
5) support multiple protocols. (TCP/IP,HTTP,PIPE,MSMQ etc)
6) can be hosted outside IIS i.e.
Manage Windows application, a window service, WAS (Window process activation service), IIS.

Command Object's Method

2009-09-01T05:20:00.000-07:00

objects exposes methods for executing commands based on the type of command and desired return value

1) ExecuteNonQuery: Executes a command that does not return any rows.
2) ExecuteReader: Returns a DataReader object.
3) ExecuteRow: Return sql record (return one datbase record)
4) ExecuteScalar: Returns a single scalar value.
5) ExecuteXMLReader: Returns an XmlReader. Available for a SqlCommand object only.

Triggers in sql server

2009-09-01T02:37:00.000-07:00

Definition:

Are special type of stored procedure that are defined to execute automatically, In place of or after data modification when Insert, Update, Delete triggering actions occurred on that table.

1) After Trigger

Fired the triggering action.
Executed automatically before the transaction is committed or rolled back.

e.g.

CREATE TRIGGER trgCheckStock ON [products]
FOR UPDATE
AS

IF( Select inStockFrom inserted) < 0)
BEGIN
PRINT 'Can not oversell products'
PRINT 'Transaction has been canceled'
END
GO

2) Instead Of Trigger

Fire in place of the triggering action.
Executed automatically before primary key and foreign key constraints are checked.

e.g.

CREATE TRIGGER trgCantDelete ON table1
INSTEAD OF DELETE
AS
PRINT 'you cannot delete this data'
GO

Resume

2009-09-01T02:36:00.000-07:00

Latest Resume - Upload a Document to Scribd

Differance between Value Type and Referance Type

2009-09-01T02:25:00.000-07:00

Value Type:

1) Stored in stack.
2) Access directly.
3) Life time determine by lifetime of variable that contain them.
4) e.g. All numeric data type, Boolean, char, Date, Structure, enumerations.

Reference Type:

1) Stored in heap.
2) Access through references.
3) Lifetime is managed by .net framework.
4) e.g. All arrays, String, Class types, Delegate.

Note: Object is not any kind of type. You can create object of structure as well as Class

Are not type: Namespaces, Modules, Events, properties, procedures, variables, constants ,& fields.

Differance between Dataset and Datareader

2009-09-01T02:09:00.000-07:00

Dataset

1) Read/write access to data.
2) Disconnected architecture.
3) Include multiple table from different database.
4) Bind to multiple controls.
5) forward and backward scanning of data.
6) supported by visual studio .net tool.
7) you can set relation between tables.

DataReader

1) Read only
2) Connected architecture.
3) Include 1 table from 1 database only.
4) Bind to one control only.
5) fast forward only.
6) Manually coded.
7) No relations.

Differance between Strucutre and Class

2009-09-01T02:03:00.000-07:00

Structure:

1) Value type stored in stack.
2) Inheritance is not possible in structure.
3) do not require constructor.
4) objects are not terminated by GC.
5) members can not be protected.

Class:

1) Reference type stored in heap.
2) Inheritance is possible.
3) Contain constructor.
4) object is terminated by GC.
3) Member can be any type.

Differeance between Interface and Abstract Class

2009-09-01T01:15:00.000-07:00

Interface:

1) Define a Contract.
2) can inherit only interfaces.
3) don't have constructor and distructor.
4) don't have concrete methods.
5) Inheritable by Structure.
6) Multiple inheritance is possible using Interface.
7) All members are Public by default.

Abstract Class:

1) Can't be initiated, partially implemented.
2) Can inherit classes & Interfaces.
3) Can have Constructor & Distructor.
4) Some methods can be concrete.
5) Not inheritable by structure.
6) Multiple inheritance not possible.
7) Members can have many modifiers.

Differance between Overloading and Overriding

2009-09-01T01:10:00.000-07:00

Overloading:

1) Same name in same/derived class but with different/type of parameter.
2) Compiletime polymorphism.
3) Having Different signature.

Overriding:

1) we need to provide different implementation than base class.
2) Runtime Polymorphism.
3) Having same signature.

Differance between Const and Readonly

2009-09-01T01:01:00.000-07:00

Const

1) Value evaluated at compile time
2) can't be static.
3) Initialize at declaration only.

e.g. const int a = 100

Readonly

1) Value evaluated at runtime.
2) Can be static.
3) can initialize at declaration or in constructor.

e.g. public readonly int doc = 5;
public program()
{ doc = 5; }

Differance between Truncate and Delete

2009-09-01T00:52:00.000-07:00

Truncate

1) Delete all rows.
2) Identity counter retain.
3) Don't make entry to transaction log. therefore it is faster.
4) DDL command.
5) can not rollback
6) do not activate trigger.

Delete

1) Delete 1 or more row depend on where clause.
2) retain Identity counter.
3) Make entery to transaction log. so it is slower.
4) DML command.
5) Can be rollback.
6) Activate trigger.