Get selected data from datatable in c#

Example

            string StudentName = "foo";

            DataTable dt = new DataTable();

            int id = (from DataRow dr in dt.Rows

                      where (string)dr["StudentName"] == StudentName

                      select (int)dr["id"]).FirstOrDefault();

Example

            DataRow[] result = datatable.Select("age >= 18");

            foreach (DataRow row in result)

            {

                Console.WriteLine("{0}, {1}", row[0], row[1]);

            }

Example
by LINQ

           var results = from myRow in myDataTable.AsEnumerable()

           where myRow.Field<int>("RowNo") == 1 select myRow;

difference betwen abstract class and virtual class

1. abstract function doesn't contain any body but a virtual function contain body
2. we must be implement the abstract function in derived class but it is not necessary for virtual function
3. abstract function can only use in abstract class but it is not necessary for virtual function
4. abstract function are called pure virtual function

Insert DataTable in to SQL Server Table using C# and VB.Net

Step 1 : Create User-Defined TableType.

CREATE TYPE [dbo].[Employee] AS TABLE(

      [Id] [int] NULL,

      [Name] [varchar](100) NULL,

      [Country] [varchar](50) NULL

)

GO

when user define type is created it will display in Object Explorer
Programability > Types > User-Defined TableTypes

or

User-Defined TableType is also created from Object Explorer
Right click on folder Programability > Types > User-Defined TableTypes
and create new  type

Step 2 : Create Stored Procedure which accept DataTable as  parameter

CREATE PROCEDURE [dbo].[Insert_Employee]

      @tblEmployee CustomerType READONLY

AS

BEGIN

      SET NOCOUNT ON;

     

      INSERT INTO Customers(CustomerId, Name, Country)

      SELECT Id, Name, Country FROM @tblEmployee

END

Step 3 : Call Stored Procedure From C# and VB

C# code

SqlCommand cmd = new SqlCommand("Insert_Employee")

cmd.CommandType = CommandType.StoredProcedure;

cmd.Connection = con;

cmd.Parameters.AddWithValue("@tblEmployee", DatatableObject);

con.Open();

cmd.ExecuteNonQuery();

con.Close();

VB code

cmd.CommandType = CommandType.StoredProcedure

cmd.Connection = con

cmd.Parameters.AddWithValue("@tblEmployee", DatatableObject)

con.Open()

cmd.ExecuteNonQuery()

con.Close()

How to call WebMethod from JQuery

Script

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js" type="text/javascript"></script>

<script type = "text/javascript">

function ShowCurrentTime() {

    $.ajax({

        type: "POST",

        url: "CS.aspx/GetCurrentTime",

        data: '{name: "' + $("#<%=txtUserName.ClientID%>")[0].value + '" }',

        contentType: "application/json; charset=utf-8",

        dataType: "json",

        success: OnSuccess,

        failure: function(response) {

            alert(response.d);

        }

    });

}

function OnSuccess(response) {

    alert(response.d);

}

</script>

WebMothod

in C# or VB

C#

[System.Web.Services.WebMethod]

public static string GetCurrentTime(string name)

{

    return "Hello " + name + Environment.NewLine + "The Current Time is: "

        + DateTime.Now.ToString();

}

VB

<System.Web.Services.WebMethod()> _

Public Shared Function GetCurrentTime(ByVal name As String) As String

   Return "Hello " & name & Environment.NewLine & "The Current Time is: " & _

            DateTime.Now.ToString()

End Function

ASP.NET Page Life Cycle Events

ASP.NET Page Life Cycle Events

At each stage of the page life cycle, the page raises some events, which could be coded. An event handler is basically a function or subroutine, bound to the event, using declarative attributes such as Onclick or handle.

Following are the page life cycle events:

PreInit - PreInit is the first event in page life cycle. It checks the IsPostBack property and determines whether the page is a postback. It sets the themes and master pages, creates dynamic controls, and gets and sets profile property values. This event can be handled by overloading the OnPreInit method or creating a Page_PreInit handler.

Init - Init event initializes the control property and the control tree is built. This event can be handled by overloading the OnInit method or creating a Page_Init handler.

InitComplete - InitComplete event allows tracking of view state. All the controls turn on view-state tracking.

LoadViewState - LoadViewState event allows loading view state information into the controls.

LoadPostData - During this phase, the contents of all the input fields are defined with the <form> tag are processed.

PreLoad - PreLoad occurs before the post back data is loaded in the controls. This event can be handled by overloading the OnPreLoad method or creating a Page_PreLoad handler.

Load - The Load event is raised for the page first and then recursively for all child controls. The controls in the control tree are created. This event can be handled by overloading the OnLoad method or creating a Page_Load handler.

LoadComplete - The loading process is completed, control event handlers are run, and page validation takes place. This event can be handled by overloading the OnLoadComplete method or creating a Page_LoadComplete handler

PreRender - The PreRender event occurs just before the output is rendered. By handling this event, pages and controls can perform any updates before the output is rendered.

PreRenderComplete - As the PreRender event is recursively fired for all child controls, this event ensures the completion of the pre-rendering phase.

SaveStateComplete - State of control on the page is saved. Personalization, control state and view state information is saved. The HTML markup is generated. This stage can be handled by overriding the Render method or creating a Page_Render handler.

UnLoad - The UnLoad phase is the last phase of the page life cycle. It raises the UnLoad event for all controls recursively and lastly for the page itself. Final cleanup is done and all resources and references, such as database connections, are freed. This event can be handled by modifying the OnUnLoad method or creating a Page_UnLoad handler.

DateTime.DaysInMonth(1980, 08);

How to get last day of the month in c#

DateTime.DaysInMonth(1980, 08);