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Monday, April 17, 2023 || Views:
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ASP.NET C# State Management ViewState Session State Application State Cookies.
This article explores various state management techniques in ASP.NET using C#. State management is essential for web applications to maintain the state of user data between requests. The article covers ViewState, Session State, Application State, and Cookies as state management techniques.
State Management in ASP.NET using C#
State Management is a critical aspect of web application development. It refers to the ability of a web application to maintain the state of user data between requests. State management is essential because HTTP is a stateless protocol. This means that each request from a client to a server is independent and doesn't remember any previous interactions. However, web applications often require state information to be maintained across multiple requests. In this article, we'll explore various state management techniques in ASP.NET using C#.
ViewState
One of the most common state management techniques in ASP.NET is ViewState. ViewState is a hidden field on an ASP.NET page that stores the state of controls on the page between postbacks. When a page is loaded, ViewState is populated with the values of controls on the page. When the page is submitted, ViewState is sent back to the server along with the form data. The server then uses ViewState to restore the state of the controls.
Let's look at an example:
<asp:TextBox ID="txtName" runat="server"></asp:TextBox>
<asp:Button ID="btnSubmit" runat="server" Text="Submit" OnClick="btnSubmit_Click" />
In the code-behind file, we can access the value of the textbox using the Text property:
protected void btnSubmit_Click(object sender, EventArgs e)
{
string name = txtName.Text;
}
In this example, the value of the textbox is lost when the page is submitted. We can use ViewState to maintain the value:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
ViewState["Name"] = txtName.Text;
}
else
{
txtName.Text = ViewState["Name"].ToString();
}
}
protected void btnSubmit_Click(object sender, EventArgs e)
{
string name = txtName.Text;
ViewState["Name"] = name;
}
In this example, we store the value of the textbox in ViewState during the Page_Load event if it's not a postback (i.e., the page is being loaded for the first time). When the page is submitted, the value is retrieved from ViewState and set back to the textbox.
Session State
Session state is another state management technique in ASP.NET that allows you to store user-specific data across multiple requests. Session state is stored on the server and is associated with a unique session ID that is sent to the client as a cookie. The client then sends the session ID back to the server with each request, allowing the server to retrieve the session data.
Let's look at an example:
Session["Name"] = "John";
In this example, we store the value "John" in the session state. We can retrieve the value on subsequent requests:
string name = (string)Session["Name"];
In this example, we retrieve the value of "Name" from the session state and cast it to a string.
Application State
Application state is similar to session state, but it's stored globally for all users of an application. Application state is useful for storing data that is used across all requests, such as configuration settings or data retrieved from a database.
Let's look at an example:
Application["ConnectionString"] = "Data Source=ServerName;Initial Catalog=DatabaseName;Integrated Security=True;";
In this example, we store a connection string in the application state. We can retrieve the value on subsequent requests:
string connectionString = (string)Application["ConnectionString"];