The dataset that you choose to populate the dropdown does not have a value called NULL. And SSRS does not give this value either when you select "Allow Null Value". So the only way that you can add this value to the dropdown is to edit the dataset query and add a string value named "NULL" to it.
The query for the dataset that populates your dropdown should look something like;
Select Distinct EmployeeNames FROM Employee_Info
Union
Select 'NULL' FROM Employee_Info
This dataset should be used to populate a dropdown with a parameter say @EmployeeName
Now for the dataset parameter set the value "NULL" as the default value.
Finally the main dataset query should look like;
Select * From Employee_Information WHERE (EmployeeName = @EmployeeName or @EmployeeName = 'NULL')
The outcome of this approach is that, the value "NULL" would be selected when you render the form by default instead of "Select a Value"
Does that make sense?
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Proposed as answer by
Challen FuModerator
Wednesday, April 07, 2010 7:18 AM
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Marked as answer by
Challen FuModerator
Monday, April 19, 2010 10:30 AM