Shalvin - Angular and Microsoft .Net Blogs

Sunday, July 6, 2008

.Net Code Access Security Introduction

CAS is the programatically means by which you secure the resouce of a system like file system, printer, registry, etc. in contrast to Role Base Security (RBS).

RequestOptional is used to grant permission to a resource.
RequestRefuse is used to revoke permission to a resource.

In following example I am going to restrict writing to C drive. Incase if user tries to write to C drive programatically he is receive an exception.

using System.Security.Permissions;
using System.Security;
using System.IO;

[assembly: FileIOPermissionAttribute(SecurityAction.RequestRefuse , Write="c:\\")]namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
StreamWriter sw;

private void button1_Click(object sender, EventArgs e)
{
sw = File.CreateText("c:\\Shalvin.txt");
sw.WriteLine("Hello");
sw.Close();
}

For a detailed coverage of Code Access Security refer http://www.codeproject.com/KB/security/UB_CAS_NET.aspx
Courtesy : Jeevan Baby, Indiaoptions

Thursday, June 26, 2008

My .Net Videos in Youtube/Google videos

Saturday, June 21, 2008

Creating Asp .Net Custom Controls

Custom Controls are reusable dlls.
Start out by creating a class library in C#. Add reference to System.Web. We are overriding the Render method of System.Web.UI.Control class and using HtmlTextWriterClass we are outputing Text to the browser.

using System.Web;
using System.Web.UI;

namespace HelloCustomCtl
{
 public class HelloCtl : Control 
 {
  protected override void Render(HtmlTextWriter writer)
  {
   writer.Write("Shalvin");
  }
 }
}

Build the project.

Testing the Custom Control

Start ASP .Net, preferably add a new tab to the toolbox. Right click the tab and select Choose Item. Click on the browse button navigate to the bin folder of previously created class library and select the dll.
Now the control will appear in the toolbox and you can use it in your project.

WebControl With Properties
Since WebControl class provides the properties, methods, and events that are common to all Web server controls, this control eventually will have a set of common properties found in common controls.
Along the way we are implementing two properties Text and Location that can be set from propeties window while using the control.

using System.Web.UI;
using System.Web.UI.WebControls;

public class MultiTdCtl : WebControl
{

private string mText;
public string Text
{
get { return mText ; }
set { mText = value; }
}

private string mLocation;
public string Location
{
get
{
return mLocation;
}
set
{
mLocation = value;
}
}

protected override void RenderContents(HtmlTextWriter writer)
{
writer.AddAttribute(HtmlTextWriterAttribute.Border, "1");
writer.RenderBeginTag(HtmlTextWriterTag.Table);
writer.RenderBeginTag(HtmlTextWriterTag.Tr);
writer.RenderBeginTag(HtmlTextWriterTag.Td);
writer.Write(mText); writer.RenderEndTag ();
writer.RenderBeginTag(HtmlTextWriterTag.Td);
writer.WriteLine(mLocation);
writer.RenderEndTag();
writer.RenderEndTag();
writer.RenderEndTag();
}
}

With C# 3.0 the lengthy getter and setter code is not required in fact you replace the code with the following :

public string Text
{
get;
set;
}
public string Location
{
get;
set;
}

..writer.RenderBeginTag(HtmlTextWriterTag.Td);
writer.Write(Text); writer.RenderEndTag ();
writer.RenderBeginTag(HtmlTextWriterTag.Td);
writer.WriteLine(Location);

Creating Composite Control

using System.Web;
using System.Web.UI.WebControls;

namespace CompositeCtl
{
public class CompositeCtl : CompositeControl
{
    Label lbl;
    TextBox txt;

   protected override void CreateChildControls()
    {
        lbl = new Label { Text = "Name" };
        this.Controls.Add(lbl);


        txt = new TextBox();
        this.Controls.Add(txt);
    }
}
}

Composite Control 2

using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace CompositeCtlEg
{
   public class ShalvinCompositeCtl : CompositeControl
    {
       Label lbl, lblMessage;
       TextBox txt;
        Button btn;
        protected override void CreateChildControls()
        {
            lblMessage = new Label { Text = "" };
            this.Controls.Add(lblMessage);
            lbl = new Label { Text = "Name" };
            this.Controls.Add(lbl);

            txt = new TextBox();
            this.Controls.Add(txt);

            btn = new Button { Text = "Shalvin" };
            btn.Click +=new EventHandler(btn_Click);
            this.Controls.Add(btn);
        }

        void btn_Click(object sender, EventArgs e)
        {
            lblMessage.Text = "Hello " + txt.Text;
        }

        protected override void RenderContents(System.Web.UI.HtmlTextWriter writer)
        {
           
            writer.RenderBeginTag(HtmlTextWriterTag.Table);

            writer.RenderBeginTag(HtmlTextWriterTag.Tr);
            writer.AddAttribute(HtmlTextWriterAttribute.Colspan, "2");
            writer.RenderBeginTag(HtmlTextWriterTag.Td);
           lblMessage.RenderControl(writer);
            writer.RenderEndTag();
            writer.RenderEndTag();

            writer.RenderBeginTag(HtmlTextWriterTag.Tr);
            writer.RenderBeginTag(HtmlTextWriterTag.Td);
            lbl.RenderControl(writer);
            writer.RenderEndTag();
            writer.RenderBeginTag(HtmlTextWriterTag.Td);
            txt.RenderControl(writer);
            writer.RenderEndTag();
            writer.RenderEndTag();

            writer.RenderBeginTag(HtmlTextWriterTag.Tr);
            writer.RenderBeginTag(HtmlTextWriterTag.Td);
            btn.RenderControl(writer);
            writer.RenderEndTag();
            writer.RenderEndTag();
            
            writer.RenderEndTag();
        }
    }
}

Wednesday, June 18, 2008

Session Asp .Net : Storing DataSet

This blog is an add on to my youtube vide ASP.Net (VB.Net) Session Variable ArrayList - Shalvin
Session state allows values to be stored in one page and accessed through out the site. Session state allows complex data to be stored whereas Query String supports only string value.
The session data is stored in the memory of Web Server.

Asp .Net uses an unique 120 bit identifier for tracking sessions. This ID is the only piece of information that is transmitted between the web server and the client. When the client presents the session ID, ASP.NET looks up the corresponding session, retrieves the serialized data from the state server, converts it to live objects, and places these objects into a special collection so they can be accessed in code. This process takes place automatically.
It is possible to store large amounts of data in a Session Variable. In this example I am constructing a dataset and assigning the contents to a Session variable and passing the showing the data of session variable on another page.

This example makes use of appSettings section of web.config to store connectionstring information. If you are not familiar with appSettings visit my blog Web.config's appSettings section to avoid hard coded memory variable

//web.config

//Default.aspx


using System.Configuration;
using System.Data.SqlClient;
public partial class _Default : System.Web.UI.Page
{
 SqlConnection cnn;
 SqlDataAdapter da;
 DataSet ds = new DataSet();
 protected void Page_Load(object sender, EventArgs e)
 {
  cnn = new SqlConnection(ConfigurationManager.AppSettings.Get	("Cnn"));

  cnn.Open();
	
  da = new SqlDataAdapter("select ProductName, UnitPrice from Products", cnn);
  da.Fill(ds, "Prod");

  Session["Prod"] = ds.Tables["Prod"];

 }
 protected void btnShowCart_Click(object sender, EventArgs e)
 {
  Response.Redirect("ShoppingCart.aspx");

 }
}


protected void Page_Load(object sender, EventArgs e)
{
 GridView1.DataSource = (DataTable)Session["Prod"];
 DataBind();
}

ASP.Net 2.0 Profile

Query String Asp .Net : Working with multiple values

Query string is the part of URL that can be used to send data as parameters. Let's first analyze the query string generated by Google on making a search for 'Shalvin'

http://www.google.co.in/search?hl=en&q=Shalvin.Here two values are passed as query string.

Create a Web site with two web pages.
In the button click of Default.aspx write the following code:

protected void sumButton_Click(object sender, EventArgs e)

{
	Response.Redirect("Sum.aspx?Val1=" + txtVal1.Text + "&Val2=" + txtVal2.Text);
}

Here is the code for extracting the value in the second page.

protected void Page_Load(object sender, EventArgs e)
{
	Response.Write("Hello " + Request.QueryString["Name"] + " your blog is " + Request.QueryString["Blog"]);
}

Calculator

<body>
    <form id="form1" runat="server">
    <div>
    
        Value 1<asp:TextBox ID="txtVal1" runat="server"></asp:TextBox>
        <asp:CompareValidator ID="CompareValidator1" runat="server" 
            ControlToValidate="txtVal1" ErrorMessage="Value cannot be string" 
            Operator="DataTypeCheck" Type="Integer"></asp:CompareValidator>
        <br />
        <br />
        Value 2<asp:TextBox ID="txtVal2" runat="server"></asp:TextBox>
        <asp:CompareValidator ID="CompareValidator2" runat="server" 
            ControlToValidate="txtVal2" ErrorMessage="Value cannot be string " 
            Operator="DataTypeCheck" Type="Integer"></asp:CompareValidator>
        <br />
        <br />
        <asp:Button ID="sumButton" runat="server" onclick="Button1_Click" Text="Button" />
    
    </div>
    </form>
</body>

Default.aspx

protected void Button1_Click(object sender, EventArgs e)

{
	Response.Redirect("Sum.aspx?Val1=" + txtVal1.Text + "&Val2=" + txtVal2.Text);
}

Sum.aspx

int i, j, res;
protected void Page_Load(object sender, EventArgs e)
{
    i = Int32.Parse(Request.QueryString["Val1"]);
    j = Int32.Parse(Request.QueryString["Val2"]);
    res = i + j;
    Response.Write(res.ToString());
}

Related Blog

ASP.Net 2.0 Profile

Session Asp .Net : Storing DataSet

Saturday, June 14, 2008

Ajax ASP .Net VII : Accordion Control and CollapsiblePanelExtender

First let's see Ajax in action.

The page is displaying Shalvin's content by default. Only headers of Site and Contact Info are visible.

When you click on Site and Blog header, it will show its contents and other contents are invisible as shown in the figure below.

Having seen the functionality lets try to implement it.
Working with Accordion is a bit tough in comparison to the controls I have already explained because you won't get a visual interface for working with Accordion and you have to work this control in source view.

If you are not familiar working with Asp .Net is source view visit my blog Asp .Net Introduction : Notepad way

Inside the Accordion tag place a Panes tag. Inside Panes you can have AccodionPane. AccordionPane inturn have Header and Content. I have added a b tag for Header. In real time you have to use CSS for better look and feel.

Accordion Databinding

Accordion control would most likely be used in conjunction with database data.

Here I am creating an SqlDataSource Control that point to Northwind database's Suppliers table.

I am setting the DataSourceId property of Accordion to the SqlDataSource id and creating HeaderTemplate and ContentTemplate as shown below.

If you are not comfortable working with templated controls visit my blog Asp .net DataList.

Result

Here I have made the header Bold and Underline. When you click on a header you can see the contents.

Adding CSS

CollapsiblePanelExtender

<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>

<asp:CollapsiblePanelExtender ID="CollapsiblePanelExtender1" runat="server"
CollapseControlID="Header"
ExpandControlID= "Header"
TargetControlID="Content">
</asp:CollapsiblePanelExtender>
</div>

<asp:Panel ID="Header" runat="server" Height="16px" Width="293px">
<u>Shalvin P D </u></asp:Panel>

<asp:Panel ID="Content" runat="server">
.Net Consultant and Corporate trainer<br /> Blog :shalvinpd.blogspot.com
</asp:Panel>

Related Blogs

Tuesday, June 10, 2008

.Net C# Multi Tier Application

The 3-Tier architecture has the following three tiers:

Data Tier

This tier consists of Database Servers. Here information is stored and retrieved. This tier keeps data neutral and independent from application servers or business logic. Giving data its own tier also improves scalability and performance.
Application Tier (Business Logic/Logic Tier): The logic tier is pulled out from the presentation tier and, as its own layer, it controls an application’s functionality by performing detailed processing.

Presentation Tier: This is the topmost level of the application. The presentation tier displays information related to such services as browsing merchandise, purchasing, and shopping cart contents. It communicates with other tiers by outputting results to the browser/client tier and all other tiers in the network.

Lets take up creating a very simple multi tier application.

First we will see the Data Tier. Here I am using Sql Server 2005 as data store.

Now we will create the Application Tier or the Business Tier. For this I am creating a Class Library Project.

using System.Data;
using System.Data.SqlClient;
using System.Configuration;

namespace ShalvinBusinessObject
{
public class BusinessObject
{
public DataTable GetCategories()
{
SqlConnection cnn;
SqlDataAdapter da;
DataSet ds = new DataSet();
cnn = new SqlConnection(@"Integrated Security=sspi;Initial Catalog=ShalvinPDBlog;Data Source=.\sqlexpress");
cnn.Open();
da = new SqlDataAdapter("spAllCategories", cnn);
da.Fill(ds, "Cat");
return ds.Tables["Cat"];
}
}

Goto Build, Build Solution for building the dll.

Creating the User Tier

Start a Windows Application Project.
Go to project, Add Reference, Select Browse and Navigate to the bin, release folder of the previously creating class library project. Select the dll.

Now you can access the dll from your project.

using ShalvinBusinessObject;

BusinessObject bo;
private void Form1_Load(object sender, EventArgs e)
{
bo = new BusinessObject();
dataGridView1.DataSource = bo.GetCategories();
}

Here I am creating an Object of the Class in the previous dll and binding an dataGridView to the GetCategories method.

sqlcmd and Sql Server

sqlcmd is a command line tool for interacting with Sql Server.

Invoke the command prompt.

If your's is a low configuration machine sqlcmd is best tool since Sql Server Management studio is resource hungry.

sqlcmd -S .\sqlexpress
>create database ShalvinPDBlog
>go
>use ShalvinPDBlog
>create table Categories (
CategoryId int primary key identity(1,1), 
CategoryName varchar(20), Description varchar(60))
>go

Here -S points to the server name.

Related Blog
Transact Sql

For more information : http://msdn.microsoft.com/en-us/library/ms162773.aspx

Shalvin - Angular and Microsoft .Net Blogs

Pages

Sunday, July 6, 2008

.Net Code Access Security Introduction

Thursday, June 26, 2008

My .Net Videos in Youtube/Google videos

Saturday, June 21, 2008

Creating Asp .Net Custom Controls

Wednesday, June 18, 2008

Session Asp .Net : Storing DataSet

ASP.Net 2.0 Profile

Query String Asp .Net : Working with multiple values

ASP.Net 2.0 Profile

Saturday, June 14, 2008

Ajax ASP .Net VII : Accordion Control and CollapsiblePanelExtender

Ajax .Net I : Extension Controls in Visual Studio 2008

Ajax .Net III : CalendarExtender Control

Ajax .Net V : FilteredTextBoxExtender

Tuesday, June 10, 2008

.Net C# Multi Tier Application

sqlcmd and Sql Server

SQL Server Authentication >sqlcmd -S .\sqlexpress -U sa -P s

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