WPF简单的数据库查询实例

<?xml version="1.0" encoding="utf-8" ?><configuration> <startup>  <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" /> </startup> <appSettings> <!--数据库连接字符串--> <add key ="ConnString" value ="Data Source=.;initial Catalog=educ; user=sa; Password=123456;Pooling=true" /> </appSettings></configuration>

namespace _03连接数据库{ class DataBaseHelper { /// 数据库打开连接的方法 ///  /// </summary> /// <returns></returns> public static SqlConnection getSqlConnection() { SqlConnection sqlConnection = new SqlConnection();  try { //获取数据库字符串 sqlConnection.ConnectionString = System.Configuration.ConfigurationSettings.AppSettings["ConnString"];  sqlConnection.Open(); sqlConnection.Close(); } catch  { throw new Exception("无法连接数据库服务器");  }  return sqlConnection; } /// sql增删改的方法 ///  /// </summary> /// <param name="sqlstr"></param> /// <returns></returns> public static int GetNonQueryEffect(string sqlstr) {  SqlConnection sqlConnection = new SqlConnection(); try { sqlConnection.Open(); //创建要执行的语句 SqlCommand cmd = new SqlCommand(sqlstr, sqlConnection); return cmd.ExecuteNonQuery();//返回执行语句中的错误 } catch (Exception ex) { throw new Exception(ex.ToString());  } finally { sqlConnection.Close(); sqlConnection.Dispose();//释放资源 }  } /// 读取数据的的方法  ///  /// </summary> /// <param name="sqlstr"></param> /// <returns></returns> public static DataSet GetDataset(string sqlstr) { SqlConnection conn = getSqlConnection(); try { conn.Open();//打开数据库连接 SqlDataAdapter sda = new SqlDataAdapter(sqlstr ,conn );//更新数据库的命令 DataSet ds = new DataSet(); sda.Fill(ds);//填充 return ds; } catch (Exception ex) { throw new Exception(ex.ToString ()); } finally { conn.Close(); conn.Dispose(); } }  }}

private void Button_Click_1(object sender, RoutedEventArgs e) { string str = "select *FROM student";//查询的语句 dataGrid.ItemsSource = DataBaseHelper.GetDataset(str).Tables[0].DefaultView;  } private void Button_Click_2(object sender, RoutedEventArgs e) { if (txtuserName.Text.Trim()== " ") { return; } string strr = string.Format("select *FROM student where sname='{0}'", txtuserName.Text); dataGrid.ItemsSource = DataBaseHelper.GetDataset(strr).Tables[0].DefaultView; }