How to add records in database through Repeater Control?

<asp:repeater id="cdcatalog" runat="server" onitemcommand="cdcatalog_ItemCommand" xmlns:asp="#unknown">

<HeaderTemplate>
<table border="1" width="100%">
<tr>
<th>Name</th>
<th>Password</th>
<th>Active</th>
<th>Add</th>
</tr>
</HeaderTemplate>

<itemtemplate>
<tr>
<td><asp:label id="lbl" runat="server" text="<%#Eval("uname") %>"></asp:label> </td>
<td><![CDATA[<%#Eval("upass")%>]]> </td>
<td><asp:textbox id="text_value" runat="server" text="<%# Eval("active") %>"></asp:textbox></td>
</tr>
</itemtemplate>
<footertemplate>
<tr>
<td><asp:textbox id="textbox1" runat="server"></asp:textbox></td>
<td><asp:textbox id="textbox2" runat="server"></asp:textbox></td>
<td><asp:textbox id="textbox3" runat="server"></asp:textbox></td>
<td><asp:button id="Btn_submit" runat="server" text="Add" onclick="Btn_submit_Click" /></td>
</tr>
</footertemplate></table>

</asp:repeater>

protected void cdcatalog_ItemCommand(object source, RepeaterCommandEventArgs e)
   {
       TextBox txt1 = (TextBox)e.Item.FindControl("textbox1");
       TextBox txt2 = (TextBox)e.Item.FindControl("textbox2");
       TextBox txt3 = (TextBox)e.Item.FindControl("textbox3");
       Button btn1 = (Button)e.Item.FindControl("Btn_submit");
       SqlConnection con = new SqlConnection(conn);
       if(txt1.Text!="")
       {
           string upd = "insert into login values('"+txt1.Text+"','"+txt2.Text+"','"+txt3.Text+"')";
           con.Open();
           SqlCommand cmd = new SqlCommand(upd, con);
           cmd.ExecuteScalar();
       }
           string query_login = "select * from Login";
           SqlDataAdapter da_login = new SqlDataAdapter(query_login, con);
           DataSet ds_login = new DataSet();
           da_login.Fill(ds_login);
           cdcatalog.DataSource = ds_login;
           cdcatalog.DataBind();
   }

protected void Btn_submit_Click(object sender, EventArgs E)
{
}