public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }

        private void button1_Click(object sender, EventArgs e)

        {

            SaveFileDialog saveFileDialog1 = new SaveFileDialog();

            saveFileDialog1.Filter = "CSV文件|*.CSV";

            saveFileDialog1.InitialDirectory = "D:\\20160323";

            if (saveFileDialog1.ShowDialog() == DialogResult.Cancel)

            {

                return;

            }

            else

            {

                DataSet ds = GetTables();

                string fileName1 = "Blogs";

                string fileName2 = "AspNetUsers";

                string fileName3 = "AspNetUserRoles";

                SaveCSV(ds.Tables[], fileName1);

                SaveCSV(ds.Tables[], fileName2);

                SaveCSV(ds.Tables[], fileName3);

                MessageBox.Show("CSV文件保存成功!");

            }

        }

        public DataSet GetTables()

        {

            string sql = @"select * from Blogs;

                           select * from AspNetUsers;

                           select * from AspNetUserRoles

                         ";

            SqlParameter[] parms = { };

            return SqlHelper.ExecutedataAdapter(sql, parms, CommandType.Text);

        }

        /// <summary>

        /// 将DataTable中数据写入到CSV文件中

        /// </summary>

        /// <param name="dt">提供保存数据的DataTable</param>

        /// <param name="fileName">CSV的文件路径</param>

        public void SaveCSV(DataTable dt, string fileName)

        {

            FileStream fs = new FileStream(fileName, System.IO.FileMode.Create, System.IO.FileAccess.Write);

            StreamWriter sw = new StreamWriter(fs, System.Text.Encoding.Default);

            string data = "";

            //写出列名称

            for (int i = ; i < dt.Columns.Count; i++)

            {

                data += dt.Columns[i].ColumnName.ToString();

                if (i < dt.Columns.Count - )

                {

                    data += ",";

                }

            }

            sw.WriteLine(data);

            //写出各行数据

            for (int i = ; i < dt.Rows.Count; i++)

            {

                data = "";

                for (int j = ; j < dt.Columns.Count; j++)

                {

                    data += dt.Rows[i][j].ToString();

                    if (j < dt.Columns.Count - )

                    {

                        data += ",";

                    }

                }

                sw.WriteLine(data);

            }

            sw.Close();

            fs.Close();

        }

    }