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[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;
        }