1. 連接Oracle

先引入Oracle.ManagedDataAccess.Client;

private void view_Click(object sender, EventArgs e)
        {
            string connStr = string.Empty;
            DataTable datatable = new DataTable();
            try
            {
                
               // connStr = string.Format(@"User Id=QXNCFX;Password=NJSLYORCL;  Data Source=(description=(address_list = (address = (HOST = {0})(PROTOCOL = TCP)(PORT= {1})))(connect_data=(service_name={2})));", "199.10.10.50", "1521", "orcl", "system", "oracle123");
                connStr = "User Id=QXNCFX;Password=NJSLYORCL;Data Source=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=199.10.10.50)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=orcl)))";
                using (OracleConnection conn = new OracleConnection(connStr))
                {
                    conn.Open();
                    OracleCommand comm = new OracleCommand("select * from GEO_GATE_1T", conn);
                    OracleDataAdapter adapter = new OracleDataAdapter(comm);
                    adapter.Fill(datatable);
                    if (datatable.Rows.Count > 0)
                    {
                        this.dataGridView1.DataSource = datatable;
                    }
                    conn.Close();
                }
               
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.ToString());
                Console.WriteLine("連接字符串:" + connStr);
            }

        }

2. 連接Sql server

            try
            {
                string sqlConn = @"server=DELL-PC\SQLEXPRESS1;database=OPGWDB;uid=sa;pwd=sa";
                SqlConnection conn = new SqlConnection(sqlConn);
                conn.Open();

                Console.WriteLine(conn.ServerVersion);
                DataTable dt = new DataTable();
                string sql = "Select * from dbo.Yhjsb";
                SqlDataAdapter ad = new SqlDataAdapter(sql, conn);
                ad.Fill(dt);

                conn.Close();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex);
            }

C# 鏈接數據庫