Log into the Salesforce and navigate to “Your Name | Setup | App Setup | Develop | API” and select the “Generate Enterprise WSDL”.  Copy the URL, as we will need this in our C# Application.

Now Open Visual Studio (I am using Visual Studio 2010) and create new Windows Application. The UI of the application should look like:

Right click on the “References“ folder and select “Add Service Reference“.

Now select the “Advanced“ and then select “Add Web Reference…“
Provide the URL of the generated WSDL, which we have discussed above in this tutorial.
It will prompt you for the username and password of salesforce, so provide it. After validation, it will display you below screen. Provide ” the web reference name” which will be used in program. In this case, the web reference name is “SFDC_Enterprise_WSDL“.

Add the following code in c# application:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Web.Services.Protocols;
using SFDCWebServiceExample.SFDCCustom;
using SFDCWebServiceExample.SFDC_Enterprise_WSDL;

namespace SFDCWebServiceExample
{
    public partial class Form1 : Form
    {
        private SforceService binding;
        private LoginResult lr;
        private SaveExpenditureWebServiceService myBinding = new SaveExpenditureWebServiceService();

        public Form1()
        {
            InitializeComponent();
        }

        private void btnLogin_Click(object sender, EventArgs e)
        {

            if (login())
            {
                describeGlobal();
            }
        }

        private bool login()
        {
            try
            {
                binding = new SforceService();
                binding.Timeout = 6000;
                lr = binding.login(txtUserName.Text, txtPwd.Text);
                return true;
            }
            catch (SoapException e)
            {
                MessageBox.Show(e.Message);
            }
            return false;
        }
        private void describeGlobal()
        {
            binding.Url = lr.serverUrl;
            #region[Consume Enterprise webservice]

            binding.SessionHeaderValue = new SFDC_Enterprise_WSDL.SessionHeader();
            binding.SessionHeaderValue.sessionId = lr.sessionId;
            #endregion

            //describeGlobal returns an array of object results that
            //includes the object names that are available to the logged-in user

            DescribeGlobalResult dgr = binding.describeGlobal();

            //Loop through the array echoing the object names to the console
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < dgr.sobjects.Length; i++)
            {
                sb.Append(dgr.sobjects[i].name+" , ");
            }
            MessageBox.Show(sb.ToString());
        }
   }
}

Note :
After Successful login, set the “SessionHeaderValue” and “SessionHeaderValue.sessionId”, In this program, we are displaying the comma separated name of all the available objects available to logged in user.

You can download the source code in next tutorial.

In Next tutorial we will discuss on creating the custom web service in salesforce and consuming it in .Net application using c#.

C# provide five access specifiers , they are as follows :

• public
• private
• protected
• internal
• protected internal

public :

public is the most common access specifier in C# . It can be access from anywhere, that means there is no restriction on accessibility. The scope of the accessibility is inside class as well as outside. The type or member can be accessed by any other code in the same assembly or another assembly that references it.

private :

The scope of the accessibility is limited only inside the classes or struct in which they are declared. The private members cannot be accessed outside the class and it is the least permissive access level.

protected :

The scope of accessibility is limited within the class or struct and the class derived (Inherited )from this class.

internal :

The internal access modifiers can access within the program that contain its declarations and also access within the same assembly level but not from another assembly.

protected internal :

Protected internal is the same access levels of both protected and internal. It can access anywhere in the same assembly and in the same class also the classes inherited from the same class .

<%@ Page Language="C#" AutoEventWireup="true"  CodeFile="Default.aspx.cs" Inherits="_Default" %>

<!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 runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:Button ID="btnExport" Text="Click To Export" runat="server" OnClick="btnExport_Click" />
        <br />
        <strong><span style="text-decoration: underline">
        Note :</span></strong> Excel path is picked up from web.Config
    </div>
    </form>
</body>
</html>

C# Code :

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.IO;

public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void btnExport_Click(object sender, EventArgs e)
    {
        try
        {
            string filePath = string.Empty;
            if (ConfigurationManager.AppSettings["FilePath"] != null)
            {
                filePath = ConfigurationManager.AppSettings["FilePath"].ToString();
            }

            byte[] document = this.StreamFile(filePath);
            Response.Clear();
            Response.AddHeader("content-disposition", "attachment;filename=TestExcel" + Convert.ToString(DateTime.Now.ToFileTimeUtc()) + ".xls");
            Response.Charset = "";
            Response.Cache.SetNoServerCaching();
            Response.ContentType = "application/ms-excel";
            Response.BinaryWrite(document);
            Response.End();
        }
        catch (Exception ex)
        {
            Page.RegisterStartupScript("error", "<script>alert('Some error occured. Please contact admin. ');</script>");
        }
    }

    /// <summary>
    /// Streams the file.
    /// </summary>
    /// <param name="filename">The filename.</param>
    /// <returns></returns>
    /// <remarks></remarks>
    private byte[] StreamFile(string filename)
    {
        byte[] ImageData = new byte[0];
        FileStream fs = new FileStream(filename, FileMode.Open, FileAccess.Read);
        try
        {
            // Create a byte array of file stream length
            ImageData = new byte[fs.Length];
            //Read block of bytes from stream into the byte array
            fs.Read(ImageData, 0, System.Convert.ToInt32(fs.Length));
            //Close the File Stream

        }
        catch (Exception ex)
        {
            throw ex;
        }
        finally
        {
            if (fs != null)
            {
                fs.Close();
            }
        }
        return ImageData;
        //return the byte data
    }
}

Download source code of Read and Export to excel

In this example, we will consider three classes which are TestA, TestB and TestC.

namespace OOPS_Concept
{
    class TestA
    {
        public void display() { Console.WriteLine("TestA - display()"); }
    }

    class TestB : TestA
    {
        public void display() { Console.WriteLine("TestB - display()"); }
    }

    class Test
    {
        static void Main(string[] args)
        {
            TestA a;
            TestB b;

            a = new TestA();
            b = new TestB();
            a.display();  // TestA - display()
            b.display();  // TestB - display()

            a = new TestB();
            a.display();  // TestA - display()

            Console.Read();
        }
    }
}

output :

TestA – display()
TestB – display()
TestA – display()

Program will compile and run successfully but

• The Problem of above code is that, third output should be “TestB –display()” because the variable a have the object of B.
• …Test.cs(15,21): warning CS0108: ‘OOPS_Concept.TestB.display()’ hides inherited member ‘OOPS_Concept.TestA.display()’. Use the new keyword if hiding was intended.

Lets resolve the problem 1.

Keyword Virtual and Override
In C#, if you like to override the parent class method then you must mark the parent method by keyword “Virtual“ and method in derived class which intended to override the parent method should be marked by keyword “override“

Note:

1. If parent method is marked by keyword “Virtual” but child is not marked by keyword “override”, then program will compile but the parent method will not be overrided.
2. If Child method is marked by keyword “override” but parent method is not marked by keyword “virtual” then program will not compile. It will give following error :
   ‘OOPS_Concept.TestB.display()’: cannot override inherited member ‘OOPS_Concept.TestA.display()’ because it is not marked virtual, abstract, or override.

Example with keyword Virtual and override:

namespace OOPS_Concept
{
    class TestA
    {
        public virtual void display() { Console.WriteLine("TestA - display()"); }
    }

    class TestB : TestA
    {
        public override void display() { Console.WriteLine("TestB - display()"); }
    }

    class Test
    {
        static void Main(string[] args)
        {
            TestA a;
            TestB b;

            a = new TestA();
            b = new TestB();
            a.display();  // TestA - display()
            b.display();  // TestB - display()

            a = new TestB();
            a.display();  // TestA - display()

            Console.Read();
        }
    }
}

output:

TestA – display()
TestB – display()
TestB – display()

Method Hiding – Keyword new:
As discussed earlier, second point in output of first program was “Compiler generated warning message”.
Because c# also support Method Hiding. To mark method as “hiding” use keyword “new” in derived class .
Keyword “new” can be used with keyword “virtual” also.
Quick Note :
If keyword “override” is used in derive class then its override the parent method.
If Keyword “new” is used in derive class then derive method hided by parent method. As shown in below program:

namespace OOPS_Concept
{
    class TestA
    {
        public void display() { Console.WriteLine("TestA - display()"); }
    }

    class TestB : TestA
    {
        public virtual new void display() { Console.WriteLine("TestB - display()"); }
        //Instead of virtual new, new can also be written.
    }

    class TestC : TestB
    {
        public new void display() { Console.WriteLine("TestC - display()"); }
    }

    class Test
    {
        static void Main(string[] args)
        {
            TestB b;
            TestC c;

            b = new TestB();
            b.display();  // TestB - display()

            b = new TestC();
            b.display();  // TestB - display() instead of TestC - display()

            Console.Read();
        }
    }
}

Output:

TestB – display()
TestB – display()

In c# there is no keyword like “final” but the same thing is achieved by keyword “sealed“.

A class which is marked by keyword sealed cannot be inherited.

If you have ever noticed, structs are sealed. You cannot derive a class from a struct.

Example:

namespace OOPS_Concept
{
    sealed class SealedClassDemo
    {
        public void test1()
        {
            Console.WriteLine("Method Test1");
        }
    }

    class childclass : SealedClassDemo
    {
    }
}

Above code will generate an error saying that class cannot be inherited.

Sealed Method:

In C#, Methods cannot be “sealed” directly. Methods of only derived class can be made sealed with keyword sealed and override.

namespace OOPS_Concept
{
    class SealedMethodDemo
    {
        public virtual void Method1()
        {
            Console.Write("Base class Method1");
        }
    }

    class ChildClass : SealedMethodDemo
    {
        public sealed override void Method1()
        {
            Console.Write("Derived class Method1");
        }
    }
}

One of the best usage of sealed classes is when you have a class with static members. For example, the Pens and Brushes classes of the System.Drawing namespace.

readonly:

The readonly keyword is a modifier that you can use on fields. When a field declaration includes a readonly modifier, assignments to the fields introduced by the declaration can only occur as part of the declaration or in a constructor in the same class.

refer this MSDN document to read more on keyword “readonly” in C#

const:

The const keyword is used to modify a declaration of a field or local variable. It specifies that the value of the field or the local variable cannot be modified. A constant declaration introduces one or more constants of a given type. The declaration takes the form:

public const double x = 1.0, y = 2.0, z = 3.0;

Note : The readonly keyword is different from the const keyword. A const field can only be initialized at the declaration of the field. A readonly field can be initialized either at the declaration or in a constructor. Therefore, readonly fields can have different values depending on the constructor used. Also, while a const field is a compile-time constant, the readonly field can be used for runtime constants, as in the following example:

public static readonly uint l1 = (uint) DateTime.Now.Ticks;

MSDN article on const keyword

The reason of this error is that, we cannot add row of one table into another directly, we have to use the API of C# as shown below:

// This example generates the error

// ds is a dataset that has previously been populated

DataTable dt1 = ds.Tables[0];

DataTable dt2 = new DataTable();

foreach(DataRow row in dt1.Rows){

    if(row["Column1"] == 10){

        // This line generates the error...
        dt2.Rows.Add(row);

    }

}

The correct way to copy the row is :

// This example achieves the copy

// ds is a dataset that has previously been populated

DataTable dt1 = ds.Tables[0];

DataTable dt2 = new DataTable();

dt2 = dt1.Clone();

foreach(DataRow row in dt1.Rows){

    if(row["Column1"] == 10){

        // Import the Row into dt2 from dt1
        dt2.ImportRow(row);

    }

}

The best way to solve this kind of error is :

if (InvokeRequired)
                {
                    this.Invoke(new MethodInvoker(delegate
                    {
                       //Your code here, like set text box content or get text box contents etc..
                    }));
                }
                else
                {
                     // Your code here, like set text box content or get text box contents etc..
                     // SAME CODE AS ABOVE
                }

To Install MSMQ, Go to Control Panel -> Add Remove Program -> Add Windows Component and select “Message Queuing”

There are two types of Messaging Queue:

1. Public Queue:

• Provide Message routing.
• Public queues are accessed through “Machine nameQueue name”

2. Private Queue:

• Do not Provide any routing.
• Private queues are accessed through “Machine namePrivate$Queue name”.
• If MSMQ is installed on the same machine as your application then you can replace the machine name with a dot, for example “.Private$Sales”

MSMQ is deployed in two mode:
1. Workgroup mode

• only private Queue therefore no messaging routing
• only “Common” and “Trigger” components needed.

2. Domain mode

• private and public queue.
• Machine that installed MSMQ must be the part of domain and uses Active Directory.
• “Common”, “Trigger”, “Active Directory Integration”, “Routing Suport” components are needed.

MSMQ Installs two window services also:

1. Message Queueing
2. Message Queueing Triggers

Administrative interface:
To Open admin Panel , My Computer -> Manage -> Services and Applications -> Message Queueing.

Under each queue you will find following three items:

1. Queue Messages

• All the messages currently seating in Queue.
• You can view the properties of all messages but cannot change it.
• Cannot create new messages or cannot delete an individual existing messages.
• You can delete all the messages by right click on “Queue messages” and select “All Tasks | Purge”

2. Journal Messages

• During Queue creation journal can be “enabled” means a copy of message from queue is placed into journal.
• Means you have the copy of all messages of queue which is read or processed.
• Purge (Delete) messages regulary from journal otherwise its size will be increased.

3. Triggers

• Allows to register the Trigger when message is placed in Queue.
• During Trigger setting you can specify COM component or external executable.

Other than Public and Private Queue, one more Queue is present which is “System Queue”. Which cannot be modified or removed.

Under System Queue you will find following three items:
1. Journal Messages:

• During Queue creation journal can be “enabled” means a copy of message from queue is placed into journal. And if the journal is not enabled then copy of message is placed in “System queue’s journal” (condition it should be enabled at code).  Means its your choice that you want to maintain journal at system queue level or message queue level.

2. Dead – Letter Messages :

• copy of all the Messages which are not delivered or expired before deliver or expired before its read / received (condition it should be enabled at code).

3. Transactional Dead – Letter Messages:

• Same as “Dead – Letter Messages” but its for Transactional Messages.

In computing, Open Database Connectivity (ODBC) provides a standard software interface for accessing database management systems (DBMS). The designers of ODBC aimed to make it independent of programming languages, database systems, and operating systems. Thus, any application can use ODBC to query data from a database, regardless of the platform it is on or DBMS it uses.

ODBC provides a standard software API method for accessing both relational and non-relational DBMS. It was developed by the SQL Access Group in 1992 in order to facilitate easier communication between applications and databases across computing platforms. Prior to its creation, if an application needed the ability to communicate with more than a single database, it would have to support and maintain an interface for each. ODBC provides a universal middleware layer between the application and DBMS, allowing the application developers to only have to learn a single interface, nor do they have to update their software if changes are made to the DBMS specification, only the driver needs updating.

Object Linking and Embedding, Database (OLE DB):

OLE DB (Object Linking and Embedding, Database) is an API designed by Microsoft for accessing data from a variety of sources in a uniform manner. It is a set of interfaces implemented using the Component Object Model (COM). It was designed as a higher-level replacement for, and successor to, ODBC, extending its feature set to support a wider variety of non-relational databases, such as object databases and spreadsheets, powerpoint that do not necessarily implement SQL.

OLE DB separates the data store from the application that needs access to it through a set of abstractions that include the datasource, session, command and rowsets. This was done because different applications need access to different types and sources of data and do not necessarily want to know how to access functionality with technology-specific methods. OLE DB is conceptually divided into consumers and providers. The consumers are the applications that need access to the data, and the provider is the software component that implements the interface and therefore provides the data to the consumer.

1. Fundamentally we can say that ADO works in Connected environment whereas ADO.Net works in Disconnected environment.
2. In ADO, the in memory representation of data is “Recordset“, whereas in ADO.Net the in memory representation of data is “DataSet“.
3. Recordset contains only one table, but ti get the data from multiple tables JOINTS must be used.
4. DataSet contains one or more than one Table. The tables between Dataset are Known as “DataTable“.
5. In ADO, data can be accessed sequencialy with the help of RecordSet Object by using “MoveNext” method.
6. In ADO.Net, the records are present in table and therefore it can be accessed like any other collection by iterating over it or by using Primary key index.
7. In ADO.NET you open connections only long enough to perform a database operation, such as a Select or Update. You can read rows into a dataset and then work with them without staying connected to the data source. In ADO the recordset can provide disconnected access, but ADO is designed primarily for connected access.
8. There is one significant difference between disconnected processing in ADO and ADO.NET. In ADO you communicate with the database by making calls to an OLE DB provider. In ADO.NET you communicate with the database through a data adapter (an OleDbDataAdapter, SqlDataAdapter, OdbcDataAdapter, or OracleDataAdapter object), which makes calls to an OLE DB provider or the APIs provided by the underlying data source.
9. Transmitting an ADO.NET dataset between applications is much easier than transmitting an ADO disconnected recordset. To transmit an ADO disconnected recordset from one component to another, you use COM marshalling. To transmit data in ADO.NET, you use a dataset, which can transmit an XML stream.

for further read, refer this URL.