1. The following example shows how to write a "USER" cookie to a client's computer. The "USER" cookie, stores
FirstName
LastName
LastVisit
2. Create the user interface to enter FirstName and LastName. The HTML for the webform is as shown below.
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="CookiesExample.aspx.cs" Inherits="CookiesExample" % >
<html >
<head runat="server" >
<title >Write a cookie to the client computer </title >
</head >
<body >
<form id="form1" runat="server" >
<table >
<tr >
<td style="width: 100px" >
First Name </td >
<td style="width: 100px" >
<asp:TextBox ID="FirstNameTextBox" runat="server" > </asp:TextBox >
</td >
</tr >
<tr >
<td style="width: 100px" >
Last Name
</td >
<td style="width: 100px" >
<asp:TextBox ID="LastNameTextBox" runat="server" > </asp:TextBox >
</td >
</tr >
<tr >
<td style="width: 100px" >
</td >
<td style="width: 100px" >
<asp:Button ID="WriteCookieButton" runat="server" Text="Write Cookie" OnClick="WriteCookieButton_Click" / >
</td >
</tr >
<tr >
<td style="width: 100px" >
</td >
<td style="width: 100px" >
<asp:Button ID="ReadCookieButton" runat="server" Text="Read Cookie" OnClick="ReadCookieButton_Click" / >
</td >
</tr >
</table >
</form >
</body >
</html >
3. WriteCookieButton_Click event handler in the code behind file, has the code required to write the cookie to the client computer as shown below.
protected void WriteCookieButton_Click(object sender, EventArgs e)
{
// Create an instance of HttpCookie class
HttpCookie UserCookie = new HttpCookie("USER");
// Populate FirstName, LastName and LastVisit fields
UserCookie["FirstName"] = FirstNameTextBox.Text;
UserCookie["LastName"] = LastNameTextBox.Text;
UserCookie["LastVisit"] = DateTime.Now.ToString();
// Set the cookie expiration date
UserCookie.Expires = DateTime.Now.AddDays(3);
// Write the cookie to the client computer
Response.Cookies.Add(UserCookie);
}
4. ReadCookieButton_Click even handler in the code behind file has the code to read the cookie from the client computer as shown below.
protected void ReadCookieButton_Click(object sender, EventArgs e)
{
// Check if the "USER" cookie exists on the client computer
if (Request.Cookies["USER"] != null)
{
//Retrieve the "USER" cookie into a cookie object
HttpCookie UserCookie = Request.Cookies["USER"];
//Write FirstName,LastName and LastVisit values
Response.Write("First Name = " + UserCookie["FirstName"] + "
");
Response.Write("Last Name = " + UserCookie["LastName"] + "
");
Response.Write("Last Visit = " + UserCookie["LastVisit"] + "
");
}
}
5. Finally test. Run the application and enter first name and Last name and click, the write cookie button. This should write the cookie to the client's computer. Now click the read cookie button, which will read the FirstName, LastName and LastVisit information from the cookie and writes on to the webform.
Source:
http://venkataspinterview.blogspot.com/2008/11/write-and-read-cookie-aspnet-interview.html
Friday, December 11, 2009
Bind an XML to DropDownList ASP.Net C#
create an XML file in ur project
<Employees >
<Employee >
<Name >David </Name >
<ID >101 </ID >
<IsActive >true </IsActive >
</Employee >
<Employee >
<Name >Tom </Name >
<ID >102 </ID >
<IsActive >true </IsActive >
</Employee >
<Employee >
<Name >Rick </Name >
<ID >103 </ID >
<IsActive >false </IsActive >
</Employee >
<Employee >
<Name >Mark </Name >
<ID >104 </ID >
<IsActive >true </IsActive >
</Employee >
</Employees >
--------------------------------------------------------
Code sample:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
DataSet DS = new DataSet();
DS.ReadXml(Server.MapPath("Employees.xml"));
DataView DV = DS.Tables["Employee"].DefaultView;
DV.RowFilter = "IsActive='true'";
DV.Sort = "Name asc";
DropDownList1.DataSource = DV;
DropDownList1.DataValueField = "ID";
DropDownList1.DataTextField = "Name";
DropDownList1.DataBind();
}
}
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
Response.Write("Name Is : " + DropDownList1.SelectedItem.Text + " and ID is " + DropDownList1.SelectedItem.Value);
}
-------------------------------------------------------
Code Explanation:
1. Read the XML data from Employees.xml file into a DataSet. We make use of the ReadXml() method. ReadXml method loads the XML data into the dataset DS. DS.ReadXml(Server.MapPath("Employees.xml"));
2. Now you have the Data in a relational format in the dataset. Create a DataView on the employees table in the DataSet. The DefaultView property of DataTable returns the DataView.
DataView DV = DS.Tables["Employee"].DefaultView;
3. After you have created the DataView, apply the RowFilter, to select only the active employees. You apply the RowFilter as shown below.
DV.RowFilter = "IsActive='true'";
4. Now sort the data in the DataView in ascending order. We sort the data on the Name column. You can apply the sort expression on a dataview as shown below.
DV.Sort = "Name asc";
5. Finally set the DataSource, DataValueField and DataTextField properties of the dropdownlist and call the DataBind() method as shown in the below code.
DropDownList1.DataSource = DV;
DropDownList1.DataValueField = "ID";
DropDownList1.DataTextField = "Name";
DropDownList1.DataBind();
Untill now we have seen how to bind an XML file to dropdownlist. We have also seen how to create a DataView on DataTable. DataView is used for sorting and filtering the data. Now we have to get the SelecteValue and SelectedItem Text of a dropdownlist. To achieve this, follow the below steps.
1. Set the autopostback property of the dropdownlist to true. So, when ever a selection in the dropdownlist changes, the webform is posted back to the server automatically.
2. In the DropDownList1_SelectedIndexChanged event handler we can capture the employee name and id using the DropDownList1.SelectedItem.Text and DropDownList1.SelectedItem.Value properties as shown below.
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
Response.Write("Name Is : " + DropDownList1.SelectedItem.Text + " and ID is " + DropDownList1.SelectedItem.Value);
}
Source: http://venkataspinterview.blogspot.com/2008/10/bind-xml-file-to-dropdownlist.html
Employees.xml
<Employee >
<Name >David </Name >
<ID >101 </ID >
<IsActive >true </IsActive >
</Employee >
<Employee >
<Name >Tom </Name >
<ID >102 </ID >
<IsActive >true </IsActive >
</Employee >
<Employee >
<Name >Rick </Name >
<ID >103 </ID >
<IsActive >false </IsActive >
</Employee >
<Employee >
<Name >Mark </Name >
<ID >104 </ID >
<IsActive >true </IsActive >
</Employee >
</Employees >
--------------------------------------------------------
Code sample:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
DataSet DS = new DataSet();
DS.ReadXml(Server.MapPath("Employees.xml"));
DataView DV = DS.Tables["Employee"].DefaultView;
DV.RowFilter = "IsActive='true'";
DV.Sort = "Name asc";
DropDownList1.DataSource = DV;
DropDownList1.DataValueField = "ID";
DropDownList1.DataTextField = "Name";
DropDownList1.DataBind();
}
}
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
Response.Write("Name Is : " + DropDownList1.SelectedItem.Text + " and ID is " + DropDownList1.SelectedItem.Value);
}
-------------------------------------------------------
Code Explanation:
1. Read the XML data from Employees.xml file into a DataSet. We make use of the ReadXml() method. ReadXml method loads the XML data into the dataset DS. DS.ReadXml(Server.MapPath("Employees.xml"));
2. Now you have the Data in a relational format in the dataset. Create a DataView on the employees table in the DataSet. The DefaultView property of DataTable returns the DataView.
DataView DV = DS.Tables["Employee"].DefaultView;
3. After you have created the DataView, apply the RowFilter, to select only the active employees. You apply the RowFilter as shown below.
DV.RowFilter = "IsActive='true'";
4. Now sort the data in the DataView in ascending order. We sort the data on the Name column. You can apply the sort expression on a dataview as shown below.
DV.Sort = "Name asc";
5. Finally set the DataSource, DataValueField and DataTextField properties of the dropdownlist and call the DataBind() method as shown in the below code.
DropDownList1.DataSource = DV;
DropDownList1.DataValueField = "ID";
DropDownList1.DataTextField = "Name";
DropDownList1.DataBind();
Untill now we have seen how to bind an XML file to dropdownlist. We have also seen how to create a DataView on DataTable. DataView is used for sorting and filtering the data. Now we have to get the SelecteValue and SelectedItem Text of a dropdownlist. To achieve this, follow the below steps.
1. Set the autopostback property of the dropdownlist to true. So, when ever a selection in the dropdownlist changes, the webform is posted back to the server automatically.
2. In the DropDownList1_SelectedIndexChanged event handler we can capture the employee name and id using the DropDownList1.SelectedItem.Text and DropDownList1.SelectedItem.Value properties as shown below.
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
Response.Write("Name Is : " + DropDownList1.SelectedItem.Text + " and ID is " + DropDownList1.SelectedItem.Value);
}
Source: http://venkataspinterview.blogspot.com/2008/10/bind-xml-file-to-dropdownlist.html
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