Singleton Example

//Class , Only one instance is created of Singleton class.
public class Singleton
{
public int x=0;
private static Singleton Instance;
private Singleton() { }
public static Singleton instance
{
get
{
if (Instance == null)
{
Instance = new Singleton();
}
return Instance;
}
}
}

//Page Load Check for Instance
Singleton s = Singleton.instance;
Singleton s1 = Singleton.instance;

data table in ASP.NET 2.0(C#)

//Add a GridView control, one lable controls, four textbox controls and button control in the page .

DataTable myDt;
private DataTable CreateDataTable()
{
DataTable myDataTable = new DataTable();

DataColumn myDataColumn;

myDataColumn = new DataColumn();
myDataColumn.DataType = Type.GetType("System.String");
myDataColumn.ColumnName = "id";
myDataTable.Columns.Add(myDataColumn);

myDataColumn = new DataColumn();
myDataColumn.DataType = Type.GetType("System.String");
myDataColumn.ColumnName = "username";
myDataTable.Columns.Add(myDataColumn);

myDataColumn = new DataColumn();
myDataColumn.DataType = Type.GetType("System.String");
myDataColumn.ColumnName = "firstname";
myDataTable.Columns.Add(myDataColumn);

myDataColumn = new DataColumn();
myDataColumn.DataType = Type.GetType("System.String");
myDataColumn.ColumnName = "lastname";
myDataTable.Columns.Add(myDataColumn);

return myDataTable;
}
private void AddDataToTable(string id,string username, string firstname, string lastname, DataTable myTable)
{
DataRow row;

row = myTable.NewRow();

row["id"] = id;
row["username"] = username;
row["firstname"] = firstname;
row["lastname"] = lastname;

myTable.Rows.Add(row);
}
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
myDt = new DataTable();
myDt = CreateDataTable();
Session["myDatatable"] = myDt;

this.GridView1.DataSource = ((DataTable)Session["myDatatable"]).DefaultView;
this.GridView1.DataBind();
}
}

protected void btnAdd_Click(object sender, EventArgs e)
{
if (txtUserName.Text.Trim() == "")
{
this.lblTips.Text = "You must fill a username.";
return;
}
else
{
AddDataToTable(this.TextBox1.Text.Trim(),this.txtUserName.Text.Trim(), this.txtFirstName.Text.Trim(), this.txtLastName.Text.Trim(), (DataTable)Session["myDatatable"]);

GridView1.DataSource = ((DataTable)Session["myDatatable"]).DefaultView;
GridView1.DataBind();

this.txtFirstName.Text = "";
this.txtLastName.Text = "";
this.txtUserName.Text = "";
this.TextBox1.Text = "";
this.lblTips.Text = "";
}
}

Grid View with check boxe Insert all the vlue in maping tble

//DataBase

//first table

CREATE TABLE tbluser(
[UId] [int] IDENTITY(1,1) NOT NULL,
[usreId] [varchar](100) CONSTRAINT [pkuser] PRIMARY KEY CLUSTERED ,
[UserName] [varchar](100)
)
//second table

CREATE TABLE tblGroup(
[GroupId] [int] IDENTITY(1,1)CONSTRAINT [pkGroup] PRIMARY KEY CLUSTERED ,
[GroupName] [varchar](100) )

//third table

CREATE TABLE MapUserGroup(
[usreId] [varchar](100) FOREIGN KEY([Groupid]) REFERENCES [dbo].[tblGroup] ([GroupId]),
[Groupid] [int] FOREIGN KEY([usreId]) REFERENCES [dbo].[tbluser] ([usreId]))


//.cs code

SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["Master"].ConnectionString);
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
var sql = "select GroupId,GroupName from tblGroup";
DataSet ds = new DataSet();
SqlDataAdapter da = new SqlDataAdapter();
da.SelectCommand = new SqlCommand(sql, con);
da.Fill(ds);
if (ds.Tables.Count > 0)
{
gUser.DataSource = ds;
gUser.DataBind();
}
unCheckUserGrid();
}

}
private void unCheckUserGrid()
{
for (int groupcount = 0; groupcount < gUser.Rows.Count; groupcount++) { CheckBox chkGroup = (CheckBox)gUser.Rows[groupcount].FindControl("chkUser"); chkGroup.Checked = false; } } protected void gUser_RowDataBound(object sender, GridViewRowEventArgs e) { if (e.Row.RowType == DataControlRowType.Header) { CheckBox chkGHeader = (CheckBox)e.Row.FindControl("chkUHeader"); chkGHeader.Attributes.Add("onclick", "return maintainState('" + chkGHeader.ClientID + "','" + gUser.ClientID + "');"); } if (e.Row.RowIndex >= 0)
{
CheckBox chkGroup = (CheckBox)e.Row.FindControl("chkUser");
chkGroup.Attributes.Add("onclick", "return uncheckHeader('" + gUser.ClientID + "');");
}
}

string sql = string.Empty;
private void saveall()
{

ArrayList arr = new ArrayList();
CheckBox chk;
Label lbl;
int i;
foreach (GridViewRow d in gUser.Rows)
{
chk = (CheckBox)d.FindControl("chkUser");

if (chk.Checked)
{
lbl = (Label)d.FindControl("lblGroupId");
arr.Add(lbl.Text);
}
}


string userId = txtUserName.Text.Trim().Replace("'", "''");
SqlDataAdapter adp = new SqlDataAdapter("Select usreId from tbluser where usreId='" + userId + "'", con);
DataSet ds = new DataSet();
adp.Fill(ds);
SqlCommand cmd ;
if (ds.Tables[0].Rows.Count > 0)
{
string UId = ds.Tables[0].Rows[0]["usreId"].ToString();
if (arr.Count > 0)
{
for (i = 0; i <= arr.Count - 1; i++) { sql += "insert into MapUserGroup(usreId,groupid) values('" + UId + "','" + arr[i] + "')"; } con.Open(); cmd = new SqlCommand(sql, con); cmd.ExecuteNonQuery(); con.Close(); unCheckUserGrid(); } } } protected void BtnSave_Click(object sender, EventArgs e) { con.Open(); SqlCommand cmd = new SqlCommand("insert into tbluser(usreId) values('" + txtUserName.Text.Trim().Replace("'", "''") + "')", con); cmd.ExecuteNonQuery(); con.Close(); //after save in maping value saveall(); } //Design .aspx page table align="center" >
tr>
td>
span>UserName /span>
/td>
td>
asp:TextBox runat="server" ID="txtUserName" > /asp:TextBox>
/td>
/tr>
/table>
table align="center" >
tr>
td>
div style="overflow: auto">
asp:GridView ID="gUser" AutoGenerateColumns="False"
runat="server"
BackColor="White" BorderColor="#999999" BorderStyle="Double"
BorderWidth="1px" CellPadding="0" Width="100%" Font-Overline="False"
Font-Size="Small" HorizontalAlign="Center" onrowdatabound="gUser_RowDataBound" >
FooterStyle BackColor="#CCCCCC" ForeColor="Black" />
RowStyle BackColor="#EEEEEE" ForeColor="Black" />
Columns>
asp:TemplateField>
HeaderTemplate>
asp:CheckBox ID="chkUHeader" runat="server" />
/HeaderTemplate>
ItemTemplate>
asp:CheckBox ID="chkUser" runat="server" />
/ItemTemplate>
ItemStyle Width="10%" />
/asp:TemplateField>
asp:TemplateField HeaderText="Group Id" HeaderStyle-HorizontalAlign="Left">
ItemTemplate>
asp:Label ID="lblGroupId" runat="server" Font-Size="100%" Text='<%# Bind("GroupId") %>' >
/ItemTemplate>

HeaderStyle HorizontalAlign="Left">
/asp:TemplateField>


asp:TemplateField HeaderText="Group Name" HeaderStyle-HorizontalAlign="Left">
ItemTemplate>
asp:Label ID="lblGroupName" Font-Size="100%" runat="server" Text='<%# Bind("GroupName") %>'>
/ItemTemplate>

HeaderStyle HorizontalAlign="Left">
/asp:TemplateField>

/Columns>
SelectedRowStyle BackColor="#008A8C" ForeColor="White" />
HeaderStyle BackColor="#000084" Font-Bold="True" ForeColor="White" BorderStyle="Double" Font-Size="Small"
HorizontalAlign="Left" />
AlternatingRowStyle BackColor="#DCDCDC" />
/asp:GridView>

/div>

/td>
/tr>
tr>
td align="right" >
asp:Button ID="BtnSave" runat="server" onclick="BtnSave_Click" Text="Save" />
/td>
/tr>
/table>

//.Js file

function maintainState(checkall,Grid)
{
var gvTable=document.getElementById(Grid);
var control=document.getElementById(checkall);

for(var i=1;i {
if(control.checked==true)
{
gvTable.rows[i].cells[0].childNodes[0].checked=true;
}
else
{
gvTable.rows[i].cells[0].childNodes[0].checked=false;
}
}
}

function uncheckHeader(control)
{
document.getElementById(control).rows[0].cells[0].childNodes[0].checked=false;

}

var datatype in C#

Declaring local variables implicitly has some restrictions; the variable must be initialized to some expression that can not be null.

var a= 10;
var z = "Rekha";

The primary reason for its existence is the introduction of anonymous types in C#

Another point to stress is that variable inference does not work for class level fields or method arguments or anywhere else other than for local variables in a method.

Advantages :

Less typing with no loss of functionality

Increases the type safety of your code. A foreach loop using an iteration variable which is typed to var will catch silently casts that are introduced with explicit types

Makes it so you don't have to write the same name twice in a variable declaration.

Some features, such as declaring a strongly typed anonymous type local variable, require the use of var

What is difference between Physical path and Virtual path?

Physical path is the path where ur original application has
stored(actual directory path of application).

virtual path is the link between physical path and
IIS..becoz to execute the webapplication in Physical
path,it needs to be mapped on to IIS(webserver) and this
logical link between physical path and IIS is called
virtual path

Recursive method for Find all directory and inside the directory found all files

// Insert logic for processing found files here.
public static void ProcessFile(string path)
{
//Logic here in file
}

// Process all files in the directory passed in, recurse on any directories
// that are found, and process the files they contain.
public static void ProcessDirectory(string targetDirectory)
{
// Process the list of files found in the directory.
string[] fileEntries = Directory.GetFiles(targetDirectory);
foreach (string fileName in fileEntries){
ProcessFile(fileName);
}


// Recurse into subdirectories of this directory.
string[] subdirectoryEntries = Directory.GetDirectories(targetDirectory);
foreach (string subdirectory in subdirectoryEntries)
{
ProcessDirectory(subdirectory);

}
}

//call the Method

string FilePath = Request.PhysicalApplicationPath + "UploadFile";
if (Directory.Exists(FilePath))
{
ProcessDirectory(FilePath);

}

What is the difference between WCF Service and Web Service?

What is the difference between WCF Service and Web Service?

a)WCF Service supports both http and tcp protocol while webservice supports only http protocol.
b)WCF Service is more flexible than web service.

•Web services can be hosted in IIS as well as outside of the IIS. While WCF service can be hosted in IIS, Windows activation service,Self Hosting,WAS and on lots of proctols like Named Pipe,TCP etc.Here lots of people disagree how we can host the web service outside of the IIS but Here is the article for that.http://msdn.microsoft.com/en-us/library/aa529311.aspx.

•In Web Services Web Service attribute will added on the top of class. In WCF there will be a Service Contract attributes will be there. Same way Web Method attribute are added in top of method of Web service while in WCF Service Operation Contract will added on the top method.

•In Web service System.XML.Serialization is supported while in the WCF Service System.RunTime.Serialization is supported.

•WCF Services can be multithreaded via ServiceBehavior class while web service can not be.

•WCF Services supports different type of bindings like BasicHttpBinding, WSHttpBinding, WSDualHttpBinding etc.while Web services only used soap or xml for this.

•Web services are compiled into a class library assembly. A file called the service file is provided that has the extension .asmx and contains an @ WebService directive that identifies the class that contains the code for the service and the assembly in which it is located while in WCF.WCF services can readily be hosted within IIS 5.1 or 6.0, the Windows Process Activation Service (WAS) that is provided as part of IIS 7.0, and within any .NET application. To host a service in IIS 5.1 or 6.0, the service must use HTTP as the communications transport protocol.