Using A Textbox To Send Data To A Database?

i currently have multiple textboxes which input data, i'm wanting the textbox details to be sent to a database, here's how one of the textboxes look: 
<asp:TextBox ID="NameTextBox" runat="server" Text='<%# Bind("Name") %>' Visible="False" Width="300px"></asp:TextBox>

the sqldatasource:
<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:CommunityDirConnectionString %>" InsertCommand="INSERT INTO email(Name, Department, Email, Subject, Body) VALUES (@Name, @Department, @Email, @Subject, @Body)" SelectCommand="SELECT email.* FROM email"><InsertParameters>
<asp:Parameter Name="Name" />
<asp:Parameter Name="Department" />
<asp:Parameter Name="Email" />
<asp:Parameter Name="Subject" />
<asp:Parameter Name="Body" />
</InsertParameters>
</asp:SqlDataSource>

i'm wanting it to fire once the user selects a button, but i'm not sure what code needs to be placed behind the button?