How to have a parameter value automatically selected when another parameter value Selected in MS SSRS.

Step 1: Create cascade parameter in SSRS.
Step 2: One Parameter value is depend on another parameter value.
Step 3: The Depending parameter data set always return One Value.
Step 4:In Parameter Select-->Default Value Tab-->Get value from a Query-->Select Dependent data set--Select Value.

Example:
Dataset1:

select distinct

snapshot_WK

,cast(snapshot_Wkstart as date) as Snapshot_WKstart

,cast(snapshot_Wkend as date) as Snapshot_WKend

from sandbox..[Rawdata_Master](nolock)

order by snapshot_Wk

Dataset2:

select top 1

cast(snapshot_Wkstart as date) as Snapshot_WKstart

,cast(snapshot_Wkend as date) as Snapshot_WKend

from sandbox..[Rawdata_Master](nolock)

where snapshot_WK = @Reporting_Wk

Dataset2 is depend on Dataset1.Both data set are using for Parameter in Report. 

Result:When we select Snapshot_Wk in one parameter,other two parameter automatically filled with corresponding Wk_Start data and Wk_End Date.