Web and Mobile Apps Codeware

Thursday, August 8, 2013

using singleton pattern in .net | example of using the singleton patter in .net c# | Design Patterns

Design Pattern : Singleton

Singleton pattern assures that only a single object will be created for any class and the same object will be used in the application.

Example (Adding Numbers ) :

Solution Explorer

Class file (here we will be writing the code for implementing singleton pattern)

public class CommonClass
{
private static CommonClass _instance;
protected CommonClass()
{
}
public static CommonClass Instance()
{
if (_instance == null) _instance = new CommonClass();
return _instance;
}

public int addNumber(int x, int y)
{
return (x + y);
}

}

ASPX :

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

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
Enter Numbers to Add :<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox><asp:TextBox ID="TextBox2" runat="server"></asp:TextBox><br />
<asp:Button ID="Button1" runat="server" Text="Submit" OnClick="Button1_Click" />
<br />

Result 1: <asp:Label ID="Label1" runat="server" Text=""></asp:Label><br />
Result 2: <asp:Label ID="Label2" runat="server" Text=""></asp:Label>

<br />

<asp:Label ID="lblMsg" runat="server" Text="Label"></asp:Label>
</div>
</form>
</body>
</html>

Codebehind:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

public partial class ShowAddNumber : System.Web.UI.Page

{

protected void Page_Load(object sender, EventArgs e)

{

}

public void Button1_Click(object sender, EventArgs e)

{

CommonClass s1 = CommonClass.Instance();

Label1.Text = s1.addNumber(int.Parse(TextBox1.Text), int.Parse(TextBox2.Text)).ToString();

CommonClass s2 = CommonClass.Instance();

Label2.Text = s2.addNumber(int.Parse(TextBox1.Text) + 5, int.Parse(TextBox2.Text) + 5).ToString();

if (s1 == s2)

{

lblMsg.Text = "Same Object Used";

}

Output :

Tuesday, August 6, 2013

[Resolved]The XML parse error near XML text | Msg 6602 Procedure sp_xml_preparedocument, Line 1 The error description is 'Whitespace is not allowed at this location.' | Msg 8179 Could not find prepared statement with handle 0.

hi in this post i show how to resolve the error generated while XML Parsing in SQL.

Example :

DECLARE @INDEX INT
DECLARE @XMLEMPLOYEE NVARCHAR(MAX)

SET @XMLEMPLOYEE = N'<ROOT><EMPLOYEE EMPID="1" EMPNAME="CHANDAN"/>
                            <EMPLOYEE EMPID="2" EMPNAME="CHANDAN & SINGH"/> 
                     </ROOT>'

EXEC SP_XML_PREPAREDOCUMENT @INDEX OUTPUT
 ,@XMLEMPLOYEE

SELECT EMPID
 ,EMPNAME
FROM OPENXML(@INDEX, 'ROOT/EMPLOYEE') WITH (
  EMPID NVARCHAR(50)
  ,EMPNAME NVARCHAR(550)
  )

After Executing this above query, we get the error as below:

The XML parse error 0xc00ce513 occurred on line number 2, near the XML text "<EMPLOYEE EMPID="2" EMPNAME="CHANDAN & SINGH"/>".
Msg 6602, Level 16, State 2, Procedure sp_xml_preparedocument, Line 1
The error description is 'Whitespace is not allowed at this location.'.
Msg 8179, Level 16, State 5, Line 9
Could not find prepared statement with handle 0.

The problem is due to the using of ampersand(&) in the xml document.

Solution:

While creating the XML document replace the ampersand(&) with & and then re-run the query to get the correct output.

DECLARE @INDEX INT
DECLARE @XMLEMPLOYEE NVARCHAR(MAX)

SET @XMLEMPLOYEE = N'<ROOT><EMPLOYEE EMPID="1" EMPNAME="CHANDAN"/>
                            <EMPLOYEE EMPID="2" EMPNAME="CHANDAN &amp; SINGH"/> 
                     </ROOT>'

EXEC SP_XML_PREPAREDOCUMENT @INDEX OUTPUT
 ,@XMLEMPLOYEE

SELECT EMPID
 ,EMPNAME
FROM OPENXML(@INDEX, 'ROOT/EMPLOYEE') WITH (
  EMPID NVARCHAR(50)
  ,EMPNAME NVARCHAR(550)
  )

It will give the ouput as :

EMPID EMPNAME
1 CHANDAN
2 CHANDAN & SINGH

Check Data-length of the all the data in the column in Sql Server | query to check size of all the data present in the column

Taking an Example , Suppose we want to check the data-size of all the data present in a column for a Employee table :

Query :

SELECT DATALENGTH(CUSTOMER_ID) AS EMP_ID_LENGTH ,
DATALENGTH(EMPLOYEE_NAME) AS EMPLOYEE_LENGTH,
*
FROM EMPLOYEE_TABLE

Monday, August 5, 2013

changing column size in sql | Query to increase or decrease column length in sql server

Changing Column Size :

Suppose you want to change the size of a column having datatype as NVARCHAR of length 100.
We will increase it length to 200.

Query :

ALTER TABLE CUSTOMER_TABLE
ALTER COLUMN CUSTOMERNAME nvarchar(200)

Thursday, August 1, 2013

Using WebGrid in MVC 4 Razor | Example Binding WebMatrix Grid in Asp.net MVC 4 Razor | Sorting paging Grid in MVC Razor

Hi in this post i will show how to use a webgrid and also how to do paging sorting in it using Asp.net MVC Razor.

Example :

Some times @using webmatrix.data namespace is not accessible so we need to add reference for WebMatrix.Data and WebMatrix.WebData

or

you can directly copy the dll from "C:\Program Files (x86)\Microsoft ASP.NET\ASP.NET Web Pages\v2.0\Assemblies" and copy into the bin folder of the application.

Code:

@using WebMatrix.Data;
@{
var db = Database.Open("MyNewConnection");
var selectQueryString = "SELECT * FROM Employee";
var data = db.Query(selectQueryString);
var grid = new WebGrid(source: data,
defaultSort: "employeename",
rowsPerPage: 10);
grid.SortDirection = SortDirection.Ascending;
}
<!DOCTYPE html>
<html>
<head>
<title>Displaying Data Using the WebGrid</title>
<style type="text/css">
.grid { margin: 4px; border-collapse: collapse; width: 600px; }
.head { background-color: #E8E8E8; font-weight: bold; color: #FFF; }
.grid th, .grid td { border: 1px solid #C0C0C0; padding: 5px; }
.alt { background-color: #E8E8E8; color: #000; }
.empname { width: 200px; font-weight:bold;}
</style>
</head>
<body>
<h1>Employee Details</h1>
<div id="grid">
@grid.GetHtml(
tableStyle: "grid",
headerStyle: "head",
alternatingRowStyle: "alt",
columns: grid.Columns(
grid.Column("employeename", "Employee Name", style: "empname"),
grid.Column("Location", format:@<i>@item.location</i>),
grid.Column("employeeid"),
grid.Column("Salary", format:@<text>$@item.contact</text>)
)
)
</div>
</body>
</html>

In the webconfig file of the application add new connection string:

<connectionStrings>
<add name="MyNewConnection" connectionString="Data Source=.;Initial Catalog=SampleDB;Integrated Security=True"
providerName="System.Data.SqlClient" />
</connectionStrings>

Output: