select and update multiple checkbox in gridview - html

Question

I want to select multible record in one time and update them by a buttom
I searched the internet by it's always cs and I want vb.net
I did my grid view as following
<asp:GridView ID="GridView1" runat="server" AutoGenerateCheckboxColumn="True"
CheckboxColumnIndex="0" AllowSorting="true"
AutoGenerateColumns="False" DataKeyNames="USER_ID"
DataSourceID="SqlDataSource1StudentActivList" CellPadding="2">
<Columns>
<asp:TemplateField ShowHeader="False">
<ItemTemplate>
<asp:CheckBox ID="CheckBox1" runat="server" />
</ItemTemplate>
</asp:TemplateField>
<asp:BoundField DataField="FirstName" HeaderText="FirstName"
SortExpression="FirstName" />
<asp:BoundField DataField="LastName" HeaderText="LastName"
SortExpression="LastName" />
<asp:BoundField DataField="MiddleName" HeaderText="MiddleName"
SortExpression="MiddleName" />
<asp:BoundField DataField="ProgramCODE" HeaderText="ProgramCODE"
SortExpression="ProgramCODE" />
<asp:BoundField DataField="USER_NAME" HeaderText="USER_NAME"
SortExpression="USER_NAME" />
<asp:BoundField DataField="USER_Email" HeaderText="USER_Email"
SortExpression="USER_Email" />
<asp:BoundField DataField="MajorNameInEnglish" HeaderText="MajorNameInEnglish"
SortExpression="MajorNameInEnglish" />
<asp:BoundField DataField="GivenStudentID" HeaderText="GivenStudentID"
SortExpression="GivenStudentID" />
<asp:BoundField DataField="accepted" HeaderText="accepted"
SortExpression="accepted" />
<asp:BoundField DataField="Gender" HeaderText="Gender"
SortExpression="Gender" />
<asp:BoundField DataField="USER_ID" HeaderText="USER_ID" ReadOnly="True"
SortExpression="USER_ID" />
</Columns>
<SelectedRowStyle BackColor="DarkSlateBlue" ForeColor="GhostWhite" />
</asp:GridView>
<asp:SqlDataSource ID="SqlDataSource1StudentActivList" runat="server"
ConnectionString="<%$ ConnectionStrings:mydbConnectionString %>"
SelectCommand="SELECT DISTINCT [FirstName], [LastName], [MiddleName], [ProgramCODE], [USER_NAME], [USER_Email], [MajorNameInEnglish], [GivenStudentID], [accepted], [Gender], [USER_ID] FROM [DIP_StudentsActivationList]">
</asp:SqlDataSource>
<p><asp:Label ID="lblSelection" runat="server" /></p>
<asp:Button ID="btupdate" runat="server" Text="Update" />
this is the VB code(converted) it's not what i want but i think i can deal with it
Imports System.Data
Imports System.Configuration
Imports System.Web
Imports System.Web.Security
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Web.UI.WebControls.WebParts
Imports System.Web.UI.HtmlControls
Public Partial Class _Default
Inherits System.Web.UI.Page
Protected Sub Page_Load(sender As Object, e As EventArgs)
If MultiSelectGridView1.SelectedDataKeys.Count > 0 Then
lblSelection.Text = "You selected employees: "
For Each k As DataKey In MultiSelectGridView1.SelectedDataKeys
lblSelection.Text += k.Value.ToString() & ", "
Next
lblSelection.Text = lblSelection.Text.TrimEnd(","C, " "C)
Else
lblSelection.Text = "No employees selected"
End If
End Sub
End Class
and I want to change the accepted status in my database by clicking the buttom
any help please