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Topic: Passing Null Parameters Posted: 26 Sep 2007 at 12:10pm
Does anyone know how to pass null parameters into a Crystal Report through asp.net? I've tried DbNull.Value, but the report doesn't seem to get it as "null".
Any help would be wonderful - I'd rather not have to rework a bunch of stored procedures!
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Posted: 27 Sep 2007 at 2:14pm
AFAIK, you can't. Crystal will expect some sort of value. I know that it means re-working the stored procs, but your best bet would be to set some sort of "default" for the param and then have the stored proc treat that value as if it were null.
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Posted: 28 Sep 2007 at 7:24am
Thanks for your response.
As with many things in Crystal, this is very frustrating. In the Crystal IDE, you are able to pass nulls ("Set to Null Value"). I don't understand why you can't use the same functionality when calling the report from .Net.
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Posted: 28 Sep 2007 at 9:30am
I haven't looked at this in .NET 2005 yet, but in VB.NET 2003 you can do this. Using the object model and the ParameterField class, set the Value property to Nothing. This lets you pass nulls to a stored procedure via code (I cover this on page 362 of my book Crystal Reports .NET Programming).
Edited by BrianBischof - 28 Sep 2007 at 10:55am
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Posted: 28 Sep 2007 at 10:44am
Thank you Brian.
I'm actually using C#, so the value is "null" instead of nothing. I'm not sure what I was doing wrong before (I really thought I had tried this!), but it is now working!
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Posted: 28 Sep 2007 at 10:50am
Excellent!
The bad thing about Crystal is that it often gets blamed for not being able to do something, when in reality it is just poorly documented. But hey - that gives me more reasons to write these crazy books!
Edited by BrianBischof - 28 Sep 2007 at 10:53am
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