Please suggest vb.net code for downloading bulk data on single button click to specified folder with unique name(table name:-Candidate_Ref_No).

str = "SELECT Top 10 [Candidate_Ref_No]
           ,[Candidate_Name]
           ,[Photodata]
           ,[Signdata],id
       FROM [DATA_5051].[dbo].[Candidate_PhotoSign_Details]"
Dim cmd As New SqlCommand(str, Conn1)
Dim dr As SqlDataReader = cmd.ExecuteReader()
dt.Load(dr)
GridView1.DataSource = dt
GridView1.DataBind()
cmd.ExecuteNonQuery()
Conn1.Close()