WPF简单的数据库查询

做一个简单WPF连接数据库的

控件类型和名称：DataGrid：dataGrid          Button1  ：Button1              Button：   Button2               TextBox ： txtuserName

在引用App.config写数据库的连接字符串

<?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>

<add key ="ConnString" value ="Data Source=.;initial Catalog=educ; user=sa; Password=123456;Pooling=true" />
                                 Data Source=.表示本机，可以写ip地址  initial Catalog=数据库名  user=用户名 Password=密码;
写一个DataBaseHelper的数据库类

 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();
             }
         }
     }
 }

按键的代码

   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[].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[].DefaultView;
         }