按钮提交数据库为什么会被插入两次

Question

一个很简单的插入操作 
即 点击按钮 执行插入 insert into tablename(id,name) values('id','name')

Answer 1

插入的数据就按钮里面 连接数据库 执行sql语句 
没循环 加断点 也看不到
但换成存储过程就没出现重复插入了

Answer 2

protected void btnAddSupplier_Click(object sender, EventArgs e)
    {
 
  using (SqlConnection con = new SqlConnection(connstring))
            {
                con.Open();
                SqlCommand cmd = con.CreateCommand();
                SqlTransaction transaction;
                transaction = con.BeginTransaction("CBDTransaction");                cmd.Connection = con;
                cmd.Transaction = transaction;
                int k;
                try
                {
                    cmd.CommandText = "insert into tableName(id,name) value("+txtId.text+","+txtName.text+")";
                    cmd.CommandType = CommandType.Text;
                    k=(int) cmd.ExecuteNonQuery();
                    transaction.Commit();
                }
                catch (SqlException ex)
                {
                    k = 0;
                    transaction.Rollback();
                    throw new Exception(ex.Message);
                }
                finally
                {
                    con.Close();
                    cmd.Dispose();
                    if (con.State == ConnectionState.Open)
                        con.Close();
                    con.Dispose();                }
                
            }
}

Answer 3

    protected void Button1_Click(object sender, EventArgs e)
    {
string sqlcon = ConfigurationManager.ConnectionStrings["mycon"].ConnectionString.ToString();
        using (SqlConnection con = new SqlConnection(sqlcon))
        {
            con.Open();
            SqlCommand cmd = con.CreateCommand();
            SqlTransaction transaction;
            transaction = con.BeginTransaction("CBDTransaction");
            cmd.Connection = con;
            cmd.Transaction = transaction;
            int k;
            try
            {
                cmd.CommandText = "insert into tt values('" + txtid.Text.ToString() + "','" + txtuser.Text.ToString()+ "')";
                cmd.CommandType = CommandType.Text;
                k = (int)cmd.ExecuteNonQuery();
                transaction.Commit();
            }
            catch (SqlException ex)
            {
                k = 0;
                transaction.Rollback();
                throw new Exception(ex.Message);
            }
            finally
            {
                con.Close();
                cmd.Dispose();
                if (con.State == ConnectionState.Open)
                    con.Close();
                con.Dispose();            }        }    }
楼主我的，只插入一次啊！！！！！