Can't you check the Parameters.Count property to see how many items are selected and use that to determine whether an object is visible? Something like
Hi , I have a report which has two parameters 1)ENTER ID ( you can enter id ) 2) SELECT ID LIST (multiple values) .......Both of the parameters set to value ' ' /null. so when i preview report , by default parameters are set to null , it still shows empty tablix. How can i hide tablix if parameters both are not selected?
Set the visibility of the tablix to an expression: =IIF(IsNothing(Parameters!ParmName1.Value), IIF(IsNothing(Parameters!ParmName2.Value),True, False),False)
Be sure to substitute in the names of your parameters.