I have Category table like below 

C_ID   Category

1      PEN
2      BOOK

Then here is Item table

S_ID    ItemName         C_ID
-------------------------------
1                        2

2                        1      

So the challenge is when inserting catgory i want to insert the catgory C_ID into C_ID column of Item table code 

    protected void btnsubmit2_Click(object sender, EventArgs e)
    {
        int inserted = 0;
        using (SqlConnection con = new SqlConnection())
        {
            con.ConnectionString = str;
            using (SqlCommand cmd = new SqlCommand())
            {
                cmd.CommandType = CommandType.Text;
                cmd.Connection = con;
                cmd.CommandText = "INSERT INTO ItemCategory (Category) VALUES(@Category)";
                cmd.Parameters.AddWithValue("@Category", txtcategory.Text);
                con.Open();
                inserted = cmd.ExecuteNonQuery();
                con.Close();
                string message = string.Empty;
                {
                    lblMessage2.Visible = true;
                    lblMessage2.Text = "Data Submitted Successfully";
                }
                Panel pn = (Panel)btnsubmit.FindControl("Panel2");
                pn.Visible = true;
            }
        }