SQlHelper数据库连接

try
            {
                SQLHelper sqlhelper = new SQLHelper();
                //SqlDataSource sql = new SqlDataSource();
                //sql.DataSourceMode = SqlDataSourceMode.DataSet;
                DataSet ResultSet = new DataSet();
                ResultSet.Merge(sqlhelper.RunQuery_getStaffName("SELECT [StaffNo], [ChineseName] FROM [VStaffNameSection] where staffno=‘" + txtStaffNo.Text + "‘"));
                if (ResultSet.Tables[0].Rows.Count == 0)
                {
                    Page.ClientScript.RegisterStartupScript(Page.GetType(), "", "<script languge=‘javascript‘>alert(‘工号不存在，请重新输入，谢谢！‘);</script>");
                    e.Cancel = true;
                    return;
                }
            }
            catch (Exception ex)
            {

                throw ex;
            }

public class SQLHelper
{
        public DataSet RunQuery_getStaffName(string QueryString)
    {
        System.Data.SqlClient.SqlConnection DBConnection = null;
        DBConnection = new System.Data.SqlClient.SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["webConnectionString_Dept"].ToString());
        DBConnection.Open();
        SqlDataAdapter DBAdapter = default(SqlDataAdapter);
        DataSet ResultsDataSet = new DataSet();

        try
        {
            DBAdapter = new SqlDataAdapter(QueryString, DBConnection);
            DBAdapter.Fill(ResultsDataSet);
            DBConnection.Close();
        }
        catch (Exception ex)
        {
            if (DBConnection.State == ConnectionState.Open)
            {
                DBConnection.Close();
            }
        }
        return ResultsDataSet;
    }
}

<connectionStrings>

<add name="webConnectionString_Dept" connectionString="Data Source=XXX;Initial Catalog=XXX;Persist Security Info=True;User ID=XXX;Password=XXX" providerName="System.Data.SqlClient" />

</connectionStrings>