C#教务系统

C#教务系统namespace xitong { public class DataAccess { public String connstr; //连接字符串 SqlConnection conn; // 连接对象 SqlCommand cmd; //命名对象 SqlDataAdapter da;//数据适配器 public String getconn() //定义一个连接字符串的方法 { connstr = @"data source=.\SQLEXPRESS;initial catalog=sscggl;integrated security=true;"; return connstr; } public bool excutesql(string sql) //返回影响的行数 { try { conn = new SqlConnection(getconn()); conn.Open(); } catch { MessageBox.Show("数据连接失败", "温馨提示"); } try { cmd = new SqlCommand(sql, conn); cmd.ExecuteNonQuery(); // conn.Close(); return true; } catch (Exception ex) { MessageBox.Show(ex.Message, "操作失败"); return false; } finally { conn.Close(); } } public DataSet getdataset(string sql, string tablename) //返回数据集 { DataSet ds = new DataSet(); //定义一个数据集 conn = new SqlConnection(getconn()); //连接对象 conn.Open(); //打开连接 try { da = new SqlDataAdapter(sql, conn); da.Fill(ds, tablename); //conn.Close(); return ds; } catch (Exception ex) { throw new Exception(ex.ToString()); } finally { conn.Close();