Problem with Postback

[Marco Yandun]

Hi. Could anyone help me please?

I am stuck with a problem that I do not know how to solve it. I have a main page and a user control inside it. In the main page I have the fields stationId and readingDate. The code for main page is:

protected void Page_Load(object sender, EventArgs e)
{
  DateTime readingDate;
  try
  {
    readingDate = new DateTime(int.Parse(DDLYear.SelectedValue), int.Parse(DDLMonth.SelectedValue), int.Parse(DDLDay.SelectedValue));
  }
  catch
  {
     readingDate = DateTime.Now;
  }
  FCRDieselLabAnalysisModule1.StationId = int.Parse(BDDLStation.SelectedValue);
  FCRDieselLabAnalysisModule1.ReadingDate = readingDate;
}
 
In the user control I have set the StationId and ReadingDate properties and the following code in it:
 
public int StationId
{
  get
  {
    return stationId;
  }
  set
  {
    stationId = value;
  }
}
 
public DateTime ReadingDate
{
  get
  {
    return readingDate;
  }
  set
  {
    readingDate = value;
  }
}
 
protected void Page_Load(object sender, EventArgs e)
{
  FuelLabAnalysisDataTDS fuelLabAnalysisData;
  fuelLabAnalysisData = new FuelLabAnalysis ().GetFuelLabAnalysisByStationIdAndReadingDate(stationId, readingDate);
  PopulateTextBoxes(fuelLabAnalysisData);
  if (!IsPostBack)
  {
  }
}

Now the problem I am facing:

When I choose another station or readingDate, it gets the record for those conditions and populate the values to the textboxes inside the user control, which is right. The problem comes when I edit the record, change the textboxes values and click on the BCalculate button (yes, I need to do some calculations with the data), then the GetFuelLabAnalysisByStationIdAndReadingDate() function fires and fill back again with the values currently saved on the DB.
If I call the function inside "if(!IsPostBack){}" block, the problem I have then is when I change the stationId or readingDate conditions, I won't be able to populate the user control because the function to populate it is not fired.

Could anyone please help me, because I have no idea how to solve this issue and I have been for a while with this stuff.

Thanks,
Marco