小弟刚来，有个问题想问下各位高手
请看以下代码：
try
            {
                sd.InitialDirectory = Application.StartupPath + "\\";//默认路径为D盘
                sd.Filter = "备份文件(*.bak)|*.bak|所有文件(*.*)|*.*";//筛选器，文件类型
                if (sd.ShowDialog() == DialogResult.OK)
                {
                    if (!File.Exists(sd.FileName.ToString()))
                    {
                        SqlConnection con = new SqlConnection();
                        con.ConnectionString = "server=.;uid=sa;pwd=;database='" + this.db_EquipmentMS.Text + "";
                        con.Open();
                        SqlCommand com = new SqlCommand();
                        this.textBox1.Text = sd.FileName.ToString();
                        com.CommandText = "BACKUP DATABASE" + this.db_EquipmentMS.Text + "TO DISK='" + sd.FileName.ToString() + "'";
                        com.Connection = con;
                        com.ExecuteNonQuery();
                        con.Close();
                        con.Dispose();
                        MessageBox.show("数据备份成功！");
                    }
                    else
                    {
                        MessageBox.Show("请重新命名！");
                    }
                }
            }
            catch (Exception k)
            {
                MessageBox.Show(k.Message);
                return;
            }

注：
控件类型              控件名称               用途
TextBox               textBox1            显示备份文件的路径
ComboBox              comboBox1           显示数据库名称
Button                button1             备份数据库
SaveFileDialog        sa                  “另存为”对话框


上面的代码执行以后出现了10个错误
[img]http://img.blog.163.com/photo/J3MUMJ8RZcT2Z4aILwAVAg==/4506977327091346717.jpg[/img]
谁可以帮我解决一下这些问题啊