Dot Net Examples: August 2010

Tuesday, August 31, 2010

asp.net caching example: How to use output caching

OutputCaching.aspx

<%@ Page Language="C#" %>
<%@ OutputCache Duration="60" VaryByParam="None" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">
   protected void Page_Load(object sender, System.EventArgs e) {
   Label2.Text = "Present Time: ";
   Label2.Text += DateTime.Now.ToString();
   }
</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
   <title>asp.net caching example: how to use output caching</title>
</head>
<body>
   <form id="form1" runat="server">
   <div>
   <h2 style="color:Red">asp.net example: Output Caching</h2>
   <asp:Label
   ID="Label1"
   runat="server"
   Font-Size="Large"
   ForeColor="SeaGreen"
   Text="Output Caching Duration: 60 seconds."
   >
   </asp:Label>
   <br /><br />
   <asp:Label
   ID="Label2"
   runat="server"
   Font-Size="Large"
   ForeColor="DodgerBlue"
   >
   </asp:Label>
   </div>
   </form>
</body>
</html>

Sunday, August 29, 2010

How to use BulletedList display mode (DisplayMode) as LinkButton

BulletedListDisplayModeLinkButton.aspx

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

protected void BulletedList1_Click(object sender, System.Web.UI.WebControls.BulletedListEventArgs e)

{

Label1.Text = "You Choose: " + BulletedList1.Items[e.Index].Text;

}

</script>

<title>How to use BulletedList display mode (DisplayMode) as LinkButton</title>

</head>

<body>

<div>

<h2 style="color:Navy">BulletedList: DisplayMode LinkButton</h2>

<asp:Label

ID="Label1"

runat="server"

Font-Bold="true"

ForeColor="Crimson"

Font-Size="Large"

</asp:Label>

<asp:Label

ID="Label2"

runat="server"

Font-Bold="true"

ForeColor="DodgerBlue"

Text="asp.net controls"

</asp:Label>

<asp:BulletedList

ID="BulletedList1"

runat="server"

Width="275"

BorderColor="DarkBlue"

BorderWidth="2"

DisplayMode="LinkButton"

OnClick="BulletedList1_Click"

<asp:ListItem>ListView</asp:ListItem>

<asp:ListItem>FormView</asp:ListItem>

<asp:ListItem>LinqDataSource</asp:ListItem>

<asp:ListItem>XmlDataSource</asp:ListItem>

<asp:ListItem>RegularExpressionValidator</asp:ListItem>

</asp:BulletedList>

</div>

</form>

</body>

</html>

Thursday, August 26, 2010

NULL In GridView EVAL Calling Serverside Method In ItemTemplate

My Table in database look like as shown in image below, some columns contains NULL values and i'll be showing "No Records Found" instead of NULL values in GridView.

To achieve this i've written a Method in code behind and will be calling this method in ItemTemplate of GridView.

Html source of GridView

<asp:GridView ID="GridView1" runat="server"
   DataSourceID="SqlDataSource1"
   AutoGenerateColumns="false">
<Columns>
<asp:BoundField ShowHeader="true" DataField="ID"
   HeaderText="ID" />
<asp:TemplateField HeaderText="Name">
<ItemTemplate>
<asp:Label ID="Label1" runat="server"
   Text='<%# CheckNull(Eval("Name")) %>'>
</asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Location">
<ItemTemplate>
<asp:Label ID="Label1" runat="server"
   Text='<%# CheckNull(Eval("Location")) %>'>
</asp:Label>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
<asp:SqlDataSource ID="SqlDataSource1" runat="server"
ConnectionString="<%$ ConnectionStrings:ConnectionString %>"
SelectCommand="SELECT ID, Name, Location FROM Details">
</asp:SqlDataSource>

C# code for the CheckNull method

protected string CheckNull(object objGrid)
{
if (object.ReferenceEquals(objGrid, DBNull.Value))
{
return "No Record Found";
}
else
{
return objGrid.ToString();
}
}
VB.NET code behind

Protected Function CheckNull(ByVal objGrid As Object) As String
If Object.ReferenceEquals(objGrid, DBNull.Value) Then
Return "No Record Found"
Else
Return objGrid.ToString()
End If
End Function

asp.net date time example: how to get system date time

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">
   protected void Button1_Click(object sender, System.EventArgs e) {
   DateTime now = DateTime.Now;
   Label1.Text = "System DateTime[Now]: " + now.ToString();
   Label1.Text += "<br />System DateTime[ToDay]: " + now.ToLongDateString();
   }
</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
   <title>asp.net date time example: how to get system date time</title>
</head>
<body>
   <form id="form1" runat="server">
   <div>
   <h2 style="color:Green">asp.net example: DateTime.Now</h2>
   <asp:Label
   ID="Label1"
   runat="server"
   Font-Size="Large"
   ForeColor="PaleVioletRed"
   Font-Bold="true"
   Font-Italic="true"
   >
   </asp:Label>
   <br /><br />
   <asp:Button
   ID="Button1"
   runat="server"
   OnClick="Button1_Click"
   Font-Bold="true"
   Text="Get System DateTime[Now]"
   ForeColor="Magenta"
   />
   </div>
   </form>
</body>
</html>

Monday, August 23, 2010

How to use TextAlign (text align left right) in RadioButtonList

RadioButtonListTextAlign.aspx

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

protected void Button1_Click(object sender, System.EventArgs e)

{

RadioButtonList1.TextAlign = TextAlign.Left;

}

protected void Button2_Click(object sender, System.EventArgs e)

{

RadioButtonList1.TextAlign = TextAlign.Right;

}

</script>

<title>How to use TextAlign (text align left right) in RadioButtonList</title>

</head>

<body>

<div>

<h2 style="color:Navy">RadioButtonList: Change TextAlign</h2>

<asp:Label

ID="Label1"

runat="server"

Font-Bold="true"

ForeColor="DarkOrange"

Text="Color List"

</asp:Label>

<asp:RadioButtonList

ID="RadioButtonList1"

runat="server"

BackColor="DarkOrange"

ForeColor="Snow"

Font-Bold="true"

<asp:ListItem>DodgerBlue</asp:ListItem>

<asp:ListItem>Green</asp:ListItem>

<asp:ListItem>FireBrick</asp:ListItem>

<asp:ListItem>GreenYellow</asp:ListItem>

<asp:ListItem>Crimson</asp:ListItem>

</asp:RadioButtonList>

<br />

<asp:Button

ID="Button1"

runat="server"

Font-Bold="true"

ForeColor="DarkOrange"

Text="TextAlign Left"

OnClick="Button1_Click"

<asp:Button

ID="Button2"

runat="server"

Font-Bold="true"

ForeColor="DarkOrange"

Text="TextAlign Right"

OnClick="Button2_Click"

</div>

</form>

</body>

</html>

Send Email Using Gmail in ASP.NET

If you want to send email using your Gmail account or using Gmail's smtp server in ASP.NET application or if you don't have a working smtp server to send mails using your ASP.NET application or aspx page than sending e-mail using Gmail is best option.

you need to write code like this

First of all add below mentioned namespace in code behind of aspx page from which you want to send the mail.

using System.Net.Mail;

Now write this code in click event of button.

C# code

protected void Button1_Click(object sender, EventArgs e) 
{   
MailMessage mail = new MailMessage();   
mail.To.Add("kritika.yadav.ecb@gmail.com");   
mail.To.Add("kriyadav@yahoo.com");   
mail.From = new MailAddress("kritika.yadav.ecb@gmail.com");   
mail.Subject = "Email using Gmail";    
string Body = "Hi, this mail is to test sending mail"+"using Gmail in ASP.NET";   
mail.Body = Body;    
mail.IsBodyHtml = true;   
SmtpClient smtp = new SmtpClient();   
smtp.Host = "smtp.gmail.com";  
smtp.Credentials = new System.Net.NetworkCredential("YourUserName@gmail.com","YourGmailPassword");   
smtp.EnableSsl = true;   
smtp.Send(mail); 
}

VB.NET code 

Imports System.Net.Mail  
Protected  Sub Button1_Click (ByVal sender As Object, ByVal e As EventArgs)  
Dim mail As 
MailMessage=New MailMessage()mail.To.Add("kritika.yadav.ecb@gmail.com")mail.To.Add("kriyadav@yahoo.com")
mail.From=New MailAddress("kritika.yadav.ecb@gmail.com")mail.Subject ="Email using Gmail"
String Body="Hi,this mail is to test sending mail"+"using Gmail in ASP.NET"   mail.Body = Body mail.IsBodyHtml = True   
Dim smtp As SmtpClient=New SmtpClient()    
smtp.Host="smtp.gmail.com"  
smtp.Credentials=New System.Net.NetworkCredential("YourUserName@gmail.com",
"YourGmailPassword")smtp.EnableSsl=True
smtp.Send(mail) 
End Sub 
You also need to enable POP by going to settings Forwarding and POP in your gmail account

Change YourUserName@gmail.com to your gmail ID and YourGmailPassword to Your password for Gmail account and test the code.

If your are getting error mentioned below 
"The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required."

than you need to check your Gmail username and password.

If you are behind proxy Server then you need to write below mentioned code in your web.config file .
<system.net>
<defaultProxy> 
<proxy proxyaddress="YourProxyIpAddress"/> 
defaultProxy> system.net>

If you are still having problems them try changing port number to 587 .

smtp.Host = "smtp.gmail.com,587";

If you still having problems then try changing code as mentioned below

SmtpClient smtp = new SmtpClient(); 
smtp.Host="smtp.gmail.com"; 
smtp.Port = 587; 
smtp.UseDefaultCredentials=False;
smtp.Credentials=new System.Net.NetworkCredential("YourUserName@gmail.com","YourGmailPassword"); 
smtp.EnableSsl=true; 
smtp.Send(mail);

Detect Page Refresh In ASP.NET

If you have created a aspx page using C# and ASP.NET and have put a button on it. And in the Click event of this button if you are inserting some data in database , after click if user refresh the page than click event gets fired again resulting data insertion to database again, to stop events on the page getting fired on browser refresh we need to write bit of code to avoid it.

<%@ 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">

<title>Untitled Page</title>

</head>

<body>

<div>

<asp:Label ID="Label1" runat="server"

Text="Label"></asp:Label><br />

<br />

<asp:Button ID="Button1" runat="server"

OnClick="Button1_Click"

Text="Button" /></div>

</form>

</body>

</html>

Now in the Page_Load event i m creating a Session Variable and assigning System date and time to it , and in Page_Prerender event i am creating a Viewstate variable and assigning Session variable's value to it
Than in button's click event i am checking the values of Session variable and Viewstate variable if they both are equal than page is not refreshed otherwise it has been refreshed.

public partial class _Default : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { Session["CheckRefresh"] = Server.UrlDecode(System.DateTime.Now.ToString()); }  } protected void Button1_Click(object sender, EventArgs e) { if (Session["CheckRefresh"].ToString() == ViewState["CheckRefresh"].ToString()) { Label1.Text = "Hello"; Session["CheckRefresh"] = Server.UrlDecode(System.DateTime.Now.ToString()); } else { Label1.Text = "Page Refreshed"; } }  protected void Page_PreRender(object sender, EventArgs e) { ViewState["CheckRefresh"] = Session["CheckRefresh"]; } }

asp.net Cross-Page PostBack example::

CrossPagePostBack.aspx

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>asp.net cross page postback example</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<h2 style="color:Red">asp.net Cross-Page PostBack example</h2>
<asp:Label
ID="Label1"
runat="server"
Text="ProductID"
ForeColor="DodgerBlue"
>
</asp:Label>
<asp:TextBox
ID="TextBox1"
runat="server"
ForeColor="AliceBlue"
BackColor="DodgerBlue"
>
</asp:TextBox>
<br />
<asp:Label
ID="Label2"
runat="server"
Text="Product Name"
ForeColor="DodgerBlue"
>
</asp:Label>
<asp:TextBox
ID="TextBox2"
runat="server"
ForeColor="AliceBlue"
BackColor="DodgerBlue"
>
</asp:TextBox>
<br />
<asp:Button
ID="Button1"
runat="server"
Text="Submit data"
Font-Bold="true"
ForeColor="DodgerBlue"
PostBackUrl="~/NextPage.aspx"
/>
</div>
</form>
</body>
</html>

NextPage.aspx

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">
protected void Page_Load(object sender, System.EventArgs e) {
TextBox pvProductID = (TextBox)PreviousPage.FindControl("TextBox1");
TextBox pvProductName = (TextBox)PreviousPage.FindControl("TextBox2");
Label1.Text ="You came from: "+ PreviousPage.Title.ToString();
Label2.Text = "Product ID: " + pvProductID.Text.ToString();
Label2.Text += "<br />Product Name: " + pvProductName.Text.ToString();

string imageSource = "~/Images/" + pvProductID.Text + ".jpg";
Image1.ImageUrl = imageSource;
Image1.BorderWidth = 2;
Image1.BorderColor = System.Drawing.Color.DodgerBlue;
}
</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>asp.net Cross-Page PostBack example: how to submit a page to another page</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<h2 style="color:Teal">asp.net cross page postback example</h2>
<asp:Label ID="Label1" runat="server" ForeColor="Crimson">
</asp:Label>
<br />
<asp:Label ID="Label2" runat="server" ForeColor="SeaGreen">
</asp:Label>
<br />
<asp:Image ID="Image1" runat="server" />
</div>
</form>
</body>
</html>