HttpSessionState.Remove(String) Method
Definition
Important
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Deletes an item from the session-state collection.
public:
void Remove(System::String ^ name);public void Remove (string name);member this.Remove : string -> unitPublic Sub Remove (name As String)Parameters
- name
- String
The name of the item to delete from the session-state collection.
Examples
The following example shows how to store values in session state by using the Add method. It also shows how to remove values in session state by using the Remove method. A Repeater control is used to display the contents of session state on the Web page. The GetEnumerator method is used to iterate through the session-state collection and populate the Repeater control.
<%@ 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, EventArgs e)
{
// If both name and value are specified
// use the Add method to add the item to session-state.
if (!String.IsNullOrEmpty(TextBox1.Text) &
!String.IsNullOrEmpty(TextBox2.Text))
{
string itemName = Server.HtmlEncode(TextBox1.Text);
string itemValue = Server.HtmlEncode(TextBox2.Text);
Session.Add(itemName, itemValue);
// Refresh the Repeater control.
RefreshRepeater();
}
}
protected void RefreshRepeater()
{
// Use the GetEnumerator method to
// iterate through the session-state.
ArrayList values = new ArrayList();
System.Collections.IEnumerator ie = Session.GetEnumerator();
string currentSessionItemName;
while (ie.MoveNext())
{
currentSessionItemName = (string)ie.Current;
values.Add(new SessionDataDisplay(currentSessionItemName,
Session[currentSessionItemName].ToString()));
}
// Bind values ArrayList to Repeater control.
Repeater1.DataSource = values;
Repeater1.DataBind();
}
public class SessionDataDisplay
{
private string _name;
private string _value;
public SessionDataDisplay(string name, string value)
{
this._name = name;
this._value = value;
}
public string Name
{
get { return _name; }
}
public string Value
{
get { return _value; }
}
}
protected void Repeater1_ItemCommand(object source, RepeaterCommandEventArgs e)
{
// Determine which item to remove and
// use the Remove method to remove it.
RepeaterItem itemToRemove = e.Item;
string sessionItemToRemove =
((Label)itemToRemove.FindControl("Label1")).Text;
Session.Remove(sessionItemToRemove);
// Refresh the Repeater control.
RefreshRepeater();
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>HttpSessionState Example</title>
</head>
<body>
<form id="form1"
runat="server"
defaultbutton="Button1"
defaultfocus="TextBox1">
<div>
Name
<asp:TextBox ID="TextBox1"
runat="server"></asp:TextBox>
<br />
Value
<asp:TextBox ID="TextBox2"
runat="server"></asp:TextBox>
<asp:Button ID="Button1"
runat="server"
OnClick="Button1_Click"
Text="Add" />
<br />
<asp:Repeater ID="Repeater1" runat="server" OnItemCommand="Repeater1_ItemCommand">
<ItemTemplate>
<br />
SessionState Item Name:
<asp:Label ID="Label1"
runat="server"
Text='<%# DataBinder.Eval(Container.DataItem, "Name") %>'/>,
SessionState Item Value:
<asp:Label ID="Label2"
runat="server"
Text='<%# DataBinder.Eval(Container.DataItem, "Value") %>'/>
<asp:Button ID="RemoveItem"
Text="Remove"
runat="server" />
</ItemTemplate>
</asp:Repeater>
</div>
</form>
</body>
</html>
<%@ Page Language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs)
' If both name and value are specified
' use the Add method to add the item to session-state.
If (Not String.IsNullOrEmpty(TextBox1.Text) And _
Not String.IsNullOrEmpty(TextBox2.Text)) Then
Dim itemName As String = Server.HtmlEncode(TextBox1.Text)
Dim itemValue As String = Server.HtmlEncode(TextBox2.Text)
Session.Add(itemName, itemValue)
' Refresh the Repeater control.
RefreshRepeater()
End If
End Sub
Protected Sub RefreshRepeater()
' Use the GetEnumerator method to
' iterate through the session-state.
Dim values As ArrayList = New ArrayList()
Dim ie As System.Collections.IEnumerator = Session.GetEnumerator()
Dim currentSessionItemName As String
While (ie.MoveNext())
currentSessionItemName = CType(ie.Current, String)
values.Add(New SessionDataDisplay(currentSessionItemName, _
Session(currentSessionItemName).ToString()))
End While
' Bind values ArrayList to Repeater control.
Repeater1.DataSource = values
Repeater1.DataBind()
End Sub
Public Class SessionDataDisplay
Private _name As String
Private _value As String
Public Sub New(ByVal name As String, ByVal value As String)
Me._name = name
Me._value = value
End Sub
Public ReadOnly Property Name() As String
Get
Return _name
End Get
End Property
Public ReadOnly Property Value() As String
Get
Return _value
End Get
End Property
End Class
Protected Sub Repeater1_ItemCommand(ByVal source As Object, _
ByVal e As System.Web.UI.WebControls.RepeaterCommandEventArgs)
' Determine which item to remove and
' use the Remove method to remove it.
Dim itemToRemove As RepeaterItem = e.Item
Dim sessionItemToRemove As String = _
CType(itemToRemove.FindControl("Label1"), Label).Text
Session.Remove(sessionItemToRemove)
' Refresh the Repeater control.
RefreshRepeater()
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>HttpSessionState Example</title>
</head>
<body>
<form id="form1"
runat="server"
defaultbutton="Button1"
defaultfocus="TextBox1">
<div>
Name
<asp:TextBox ID="TextBox1"
runat="server"></asp:TextBox>
<br />
Value
<asp:TextBox ID="TextBox2"
runat="server"></asp:TextBox>
<asp:Button ID="Button1"
runat="server"
OnClick="Button1_Click"
Text="Add" />
<br />
<asp:Repeater ID="Repeater1" runat="server" OnItemCommand="Repeater1_ItemCommand">
<ItemTemplate>
<br />
SessionState Item Name:
<asp:Label ID="Label1"
runat="server"
Text='<%# DataBinder.Eval(Container.DataItem, "Name") %>'/>,
SessionState Item Value:
<asp:Label ID="Label2"
runat="server"
Text='<%# DataBinder.Eval(Container.DataItem, "Value") %>'/>
<asp:Button ID="RemoveItem"
Text="Remove"
runat="server" />
</ItemTemplate>
</asp:Repeater>
</div>
</form>
</body>
</html>
Remarks
If the session-state collection does not contain an element with the specified name, the collection remains unchanged. No exception is thrown.
Applies to
See also
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