Message "Expression in Text property of 'Text1" can't be evaluated!"

Fabio Pagano · Post by **Fabio Pagano** » Tue Dec 04, 2007 6:49 am

Using Vs2005, StimulReport version 2007.3.30.0 and C# as report language.

In a datetime dictionary field, if i pass a "null" value", in design preview i see the message "Expression in Text property of 'Text1" can't be evaluated!" (in the lower panel, where compiler messages appear).

Doesn't seem a critical message, but i need to know if there is a problem anyway.

Thanks.

EDV Gradl · Post by **EDV Gradl** » Tue Dec 04, 2007 7:13 am

Couldn't you use a DateTime? field?

Marco

Fabio Pagano · Post by **Fabio Pagano** » Tue Dec 04, 2007 7:17 am

It's already a datetime field.

EDV Gradl · Post by **EDV Gradl** » Tue Dec 04, 2007 7:35 am

Yes and what if you use a DateTime? (nullable) field?

Marco

raja · Post by **raja** » Tue Dec 04, 2007 7:37 am

Are you referring the database column using this format, DATASOURCE_NAME.COLUMN_NAME, if yes, then you should not use that (esp. for numeric and date columns), instead use the format, DATASOURCE_NAME("COLUMN_NAME").

Fabio Pagano · Post by **Fabio Pagano** » Tue Dec 04, 2007 7:41 am

EDV wrote:Yes and what if you use a DateTime? (nullable) field?

With "DateTime (nullable)" it works, but if the datasource comes from a datatable with a datetime field in it, it is automatically created in StimulReport as "DateTime", not "DateTime (nullable)".

Post by **Vital** » Tue Dec 04, 2007 4:21 pm

Hello Fabio,

With "DateTime (nullable)" it works, but if the datasource comes from a datatable with a datetime field in it, it is automatically created in StimulReport as "DateTime", not "DateTime (nullable)".

Our report engine get data using standard Ado.Net. By default Ado.Net use DateTime type.

Thank you.

Fabio Pagano · Post by **Fabio Pagano** » Tue Dec 04, 2007 4:38 pm

Vital wrote:Our report engine get data using standard Ado.Net. By default Ado.Net use DateTime type.

Well, so why does the message "Expression in Text property of 'Text1" can't be evaluated!" appear when the value in a datetime field is null? How can i avoid it? (Note: it's not a critical message, only a warning that i see only in preview design).

Thanks.

Brendan · Post by **Brendan** » Tue Dec 04, 2007 5:36 pm

The reason it appears is because the report engine attempts to convert the field to a datetime and because the value is null it cannot conver the value, instead leaving the text component blank instead of containing Date text