Looping through SQLdatareader and comparing row values - sql

Question

I have a function that calls a stored procedure. I need to compare the result to an input parameter. I keep getting a warning that the function does not return on all code paths, but I can't figure out where.
So, 2 questions:
1. Am I looping through the SqlDataReader correctly or should I fill a datatable with my reader results?
2. Where am I missing a return value?
Function code:
Function FZCheck(FZ As String) As Boolean
Dim constr As String = My.Settings.devTOD.ToString
Dim con As New SqlConnection(constr)
Dim cmd As New SqlCommand("spSelectFloodZones", con)
cmd.CommandType = CommandType.StoredProcedure
If con.State = ConnectionState.Closed Then
con.Open()
End If
Dim rdr As SqlDataReader
rdr = cmd.ExecuteReader
If rdr.HasRows Then
Do While rdr.Read
If String.Equals(rdr(0).ToString, FZ) = True Then
Return True
Else
Return False
End If
Loop
Else
Return False
End If
If con.State = ConnectionState.Open Then
con.Close()
End If
rdr.Close()
End Function
Stored proc code: (very simple)
ALTER PROCEDURE [dbo].[spSelectFloodZones]
AS
SET NOCOUNT ON
SET ROWCOUNT 0
-- ====================
-- Select flood zones
-- ====================
SELECT DISTINCT FloodZone
FROM TOD.dbo.FloodZones
Language is VB.NET, using SQL Server 2012.

Answer 1

Here you go with some minor refactoring.
Function FZCheck(FZ As String) As Boolean
Dim constr As String = My.Settings.devTOD.ToString
Dim con As New SqlConnection(constr)
Dim result As Boolean = False
Dim cmd As New SqlCommand("spSelectFloodZones", con)
cmd.CommandType = CommandType.StoredProcedure
If con.State = ConnectionState.Closed Then
con.Open()
End If
Dim rdr As SqlDataReader
rdr = cmd.ExecuteReader
If rdr.HasRows Then
Do While rdr.Read
If String.Equals(rdr(0).ToString, FZ) = True Then
result = True
End If
Loop
End If
If con.State = ConnectionState.Open Then
con.Close()
End If
rdr.Close()
Return result
End Function