Insert data to sql server from Textbox which is in a loop

Question

Getting data from SQL Table

using (var con = new SqlConnection(constr))
{
string query = "select * from higher_office";
using (var cmd = new SqlCommand(query, con))
{
using (var sda = new SqlDataAdapter())
{
cmd.Connection = con;
sda.SelectCommand = cmd;
using (TableData)
{
TableData.Clear();
sda.Fill(TableData);
}
}
}
}

aspx fetched data and new Textbox for inputing values corresponding to higher office

<% for (var data = 0; data < TableData.Rows.Count; data++)
{
%>
<tr>
<td>
<%=TableData.Rows[data]["higher_office_ID"]%>
</td>
<td>
<%=TableData.Rows[data]["higher_office_Name"]%>
</td>
<td>
<asp:TextBox ID="TextBox1" runat="server" width="150px" ></asp:TextBox>
</td>
</tr>
<% } %>

trying to insert as follows but not excute

using (SqlConnection con = new SqlConnection(constr))
{
con.Open();
//SqlCommand cm = new SqlCommand("insert into item_distribution (sector,quantity) values('" + id + "','" + amount+ "')", con);
for (int i = 1; i <= rowCount; i++)
{
SqlCommand cm = new SqlCommand("insert into item_distribution (sector,quantity) values('"+ id +"','"+ amount+"')",con);
try
{
cm.ExecuteNonQuery();
RoleMessage.Text += "Successfully inserted";
RoleMessageDIV.Style["display"] = "block";
}
catch(Exception ex )
{
RoleMessage.Text +="Not inserted "+ex;
RoleMessageDIV.Style["display"] = "block";
}
}
con.Close();
}