相关疑难解决方法(0)

让我们首先解决这个问题:我使用MS Access DB时遇到困难,我无法改变它.

这很好用:

using (OleDbConnection conn = ConnectionHelper.GetConnection())
{
  conn.Open();
  var results = conn.Query<string>(
    "select FirstName from Students where LastName = @lastName", 
    new { lastName= "Smith" }
  );
  conn.Close();
}

这很好用:

using (OleDbConnection conn = ConnectionHelper.GetConnection())
{
  OleDbCommand cmd = new OleDbCommand(
    "update Students set FirstName = @firstName, City = @city where LastName = @lastName", 
    conn
  );
  cmd.Parameters.AddWithValue("firstName", "John");
  cmd.Parameters.AddWithValue("city", "SomeCity");
  cmd.Parameters.AddWithValue("lastName", "Smith");

  conn.Open();
  var result = cmd.ExecuteNonQuery();
  conn.Close();
}

这不会......它执行时没有错误,但它将FirstName设置为DB中的"SomeCity",将City设置为"John":

using (OleDbConnection conn = ConnectionHelper.GetConnection())
{
  conn.Open();
  var …