Wildcard Syntax NO RESULTS WHEN Using Preview Data

Hello

 I have come across a problem today when working with data sets/table adapter in vs05 for use in ASP.net.

SELECT  ws_Agent.Telephone, ws_Agent.Email, ws_Agent.Name, ws_Agent.AgentId, ws_Agent.forename, ws_Agent.surname, ws_Agent.Acc_PcentreID, ws_ProfitCentre.ShortCode, ws_Branch.Name AS branchname, ws_Branch.ManagerId,
            ws_Branch.Fax AS branchFax, ws_Branch.Telephone AS branchtelephone, ws_Branch.Address1, ws_Branch.Address4, ws_Branch.Postcode, ws_ProfitCentre.Telephone AS PCentreTelephone,
            ws_ProfitCentre.Status AS PCentreStatus, ws_ProfitCentre.Fax AS PCentreFax, ws_ProfitCentre.Email AS PCentreEmail, ws_Agent.Status, ws_Agent.DisableAccount, ws_ProfitCentre.PCentreID,
            ws_Branch.Status AS BranchStatus
FROM    ws_Agent INNER JOIN
            ws_ProfitCentre ON ws_Agent.Acc_PcentreID = ws_ProfitCentre.PCentreID INNER JOIN
            ws_Branch ON ws_ProfitCentre.BranchID = ws_Branch.BranchId
WHERE  (ws_Agent.Status <> 3) AND (ws_ProfitCentre.Status = 0) AND (ws_Agent.forename LIKE  @forename) AND (ws_Agent.surname LIKE  @surname ) AND
            (ws_ProfitCentre.ShortCode LIKE  @profitcentreshortcode) AND (ws_Branch.Name LIKE @branchname )

The wildcard syntax works fine when tested in the query builder when passing in % to the parameters

 , but does not work correctly NO RESULTS WHEN using preview data and in the subsequent use of data set in code.

Can anyone please comment on this or is there a setting I have missed?

Regards,

Matthew