c# - "try"应该在资源分配之前还是之后？

Question

在 Delphi 世界中，至少有人认为最好在资源分配之后进行尝试，例如:

OracleCommand oc = new OracleCommand(query, con);
try
begin
  oc.CommandType = CommandType.Text;
  String s = oc.ExecuteScalar().ToString();
  try            
    return s;            
    except (on OracleException ex)
    begin
      ShowMessage(ex.Message);
      result := string.Empty;
    end;
end
finally
begin
  con.Close();
  con.Dispose();
end;

在 C# 中是否相同，或者“try”应该先于资源分配:

try
{
  OracleCommand oc = new OracleCommand(query, con);
  oc.CommandType = CommandType.Text;
  String s = oc.ExecuteScalar().ToString();
  try
  {
    return s;
  }
  catch (OracleException ex)
  {
    MessageBox.Show(ex.Message);
    return string.Empty;
  }
}
finally
{
  con.Close();
  con.Dispose();
}

?

Answer 1

还有一个更好的解决方案:using陈述。除了这段代码，您可以编写惯用的

using (Connection con = /* some initialization logic */)
{
    try
    {
        using (OracleCommand oc = new OracleCommand(query, con))
        {
            oc.CommandType = CommandType.Text;
            return oc.ExecuteScalar().ToString();
        } // oc is automatically disposed here
    }
    catch (OracleException ex)
    {
        MessageBox.Show(ex.Message);
        return string.Empty;
    }
} // con is automatically disposed here