Posts Tagged ‘DevExpress’

TcxEdit Validation

Friday, October 21st, 2011

If you assign the Min and Max Value properties of a TcxEdit descendant, the control will call the OnValidate event handler indicating there is no error, but a subsequent attempt to convert the displayvalue into the target datatype and check if the result is within the range specified will result in an exception being raised. If you’re using something like Eurekalog or MadExcept to trap all unhandled exceptions this can be a major pain in the derrier.

There are only two ways I’ve found to deal with this issue:

1) Tell MadExcept or Eurekalog not to process this exception type

2) Do not define the Min and Max values in the control. Instead let the hcOPF validator deal with this, and I populate the OnValidate event with the following code to prevent an earlier exception from being raised (this code is for a cxDateTimeEdit):

if Error then
  MessageDlg('The Date Entered is not Valid!',mtWarning,[mbOk],0);
  DisplayValue := DateTimeToStr(Now);  //reset the display to a valid value
  Error := False;  //don't raise an exception since we've handled the error