WPF簡單的數據庫查詢

 做一個簡單WPF連接數據庫的

控件類型和名稱：DataGrid：dataGrid          Button1  ：Button1              Button：   Button2               TextBox ： txtuserName

 在引用App.config寫數據庫的連接字符串

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
    </startup>
   <appSettings>
    <!--數據庫連接字符串-->
    <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=.表示本機，可以寫ip地址 initial Catalog=數據庫名 user=用戶名 Password=密碼;
寫一個DataBaseHelper的數據庫類

namespace _03連接數據庫
{
    class DataBaseHelper
    {

        /// 數據庫打開連接的方法
        /// 
        /// </summary>
        /// <returns></returns>
        public static SqlConnection getSqlConnection()
        {
            SqlConnection sqlConnection = new SqlConnection();          
            try
            {
                 //獲取數據庫字符串
                sqlConnection.ConnectionString = System.Configuration.ConfigurationSettings.AppSettings["ConnString"];           
                sqlConnection.Open();
                sqlConnection.Close();
            }
            catch 
            {

                throw new Exception("無法連接數據庫服務器"); 
            }
          
            return sqlConnection;
        }

        /// sql增刪改的方法
        /// 
        /// </summary>
        /// <param name="sqlstr"></param>
        /// <returns></returns>
        public static int GetNonQueryEffect(string sqlstr)
        {        
            SqlConnection sqlConnection = new SqlConnection();
            try
            {
                sqlConnection.Open();
                //創建要執行的語句
                SqlCommand cmd = new SqlCommand(sqlstr, sqlConnection);
                return cmd.ExecuteNonQuery();//返回執行語句中的錯誤
            }
            catch (Exception ex)
            {
                throw new Exception(ex.ToString());
                
            }
            finally
            {
                sqlConnection.Close();
                sqlConnection.Dispose();//釋放資源
            }
          
        }

         ///  讀取數據的的方法    
         ///  
         /// </summary>
         /// <param name="sqlstr"></param>
         /// <returns></returns>
        public static DataSet GetDataset(string sqlstr)
        {
            SqlConnection conn = getSqlConnection();
            try
            {
                conn.Open();//打開數據庫連接
                SqlDataAdapter sda = new SqlDataAdapter(sqlstr ,conn );//更新數據庫的命令
                DataSet ds = new DataSet();
                sda.Fill(ds);//填充
                return ds;
            }
            catch (Exception ex)
            {

                throw new Exception(ex.ToString ());
            }
            finally
            {
                conn.Close();
                conn.Dispose();
            }
        }    
    }
}

 按鍵的代碼

  private void Button_Click_1(object sender, RoutedEventArgs e)
        {
            string str = "select *FROM student";//查詢的語句
            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;
        }