Save and retrieve database data from Cache using C# and VB.Net in ASP.Net

Check this example. Now please take its reference and correct your code.

Database

For this example I have used of Northwind database that you can download using the link given below.

Download Northwind Database

HTML

<asp:ListView ID="lvCustomers" runat="server" GroupPlaceholderID="groupPlaceHolder1"
    ItemPlaceholderID="itemPlaceHolder1">
    <LayoutTemplate>
        <table cellpadding="0" cellspacing="0">
            <tr>
                <th>CustomerId</th>
                <th>ContactName</th>
                <th>Country</th>
            </tr>
            <asp:PlaceHolder runat="server" ID="groupPlaceHolder1"></asp:PlaceHolder>
        </table>
    </LayoutTemplate>
    <GroupTemplate>
        <tr><asp:PlaceHolder runat="server" ID="itemPlaceHolder1"></asp:PlaceHolder></tr>
    </GroupTemplate>
    <ItemTemplate>
        <td><%# Eval("CustomerId") %></td>
        <td><%# Eval("ContactName") %></td>
        <td><%# Eval("Country") %></td>
    </ItemTemplate>
</asp:ListView>

Namespaces

C#

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

VB.Net

Imports System.Configuration
Imports System.Data
Imports System.Data.SqlClient

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        this.BindListView();
    }
}

private void BindListView()
{
    lvCustomers.DataSource = GetData();
    lvCustomers.DataBind();
}

private DataTable GetData()
{
    DataTable dt = new DataTable();
    if (Cache["DataTable"] == null)
    {
        string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
        using (SqlConnection con = new SqlConnection(constr))
        {
            using (SqlCommand cmd = new SqlCommand())
            {
                cmd.CommandText = "SELECT TOP 5 CustomerId, ContactName, Country FROM Customers";
                cmd.Connection = con;
                using (SqlDataAdapter sda = new SqlDataAdapter(cmd))
                {
                    sda.Fill(dt);
                    Cache.Insert("DataTable", dt, null, DateTime.Now.AddDays(5), System.Web.Caching.Cache.NoSlidingExpiration);
                }
            }
        }
    }
    else
    {
        dt = Cache["DataTable"] as DataTable;
    }

    return dt;
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Me.BindListView()
    End If
End Sub

Private Sub BindListView()
    lvCustomers.DataSource = GetData()
    lvCustomers.DataBind()
End Sub

Private Function GetData() As DataTable
    Dim dt As DataTable = New DataTable()
    If Cache("DataTable") Is Nothing Then
        Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
        Using con As SqlConnection = New SqlConnection(constr)
            Using cmd As SqlCommand = New SqlCommand()
                cmd.CommandText = "SELECT TOP 5 CustomerId, ContactName, Country FROM Customers"
                cmd.Connection = con
                Using sda As SqlDataAdapter = New SqlDataAdapter(cmd)
                    sda.Fill(dt)
                    Cache.Insert("DataTable", dt, Nothing, DateTime.Now.AddDays(5), System.Web.Caching.Cache.NoSlidingExpiration)
                End Using
            End Using
        End Using
    Else
        dt = TryCast(Cache("DataTable"), DataTable)
    End If

    Return dt
End Function