Invalid attempt to call Read when reader is closed. vb.net - vb.net

Question

I have this sub in my WinForm:
Public Function CheckSentToday(ByVal date1 As DateTime) As Boolean
Dim cmSql As New SqlCommand("Check_Today", cnSql)
Try
cmSql.CommandType = CommandType.StoredProcedure
cmSql.Parameters.AddWithValue("#date1", String.Format("{0:yyyy-MM-dd}", date1))
If Not cnSql Is Nothing AndAlso cnSql.State = ConnectionState.Closed Then cnSql.Open()
If cmSql.ExecuteScalar IsNot Nothing Then
Return True
Else
Return False
End If
Catch ex As Exception
WriteToText("CheckSentToday", ex.ToString)
CheckSentToday = False
Finally
If Not cnSql Is Nothing AndAlso cnSql.State = ConnectionState.Open Then cnSql.Close()
End Try
End Function
I am opening the connection before executing the SqlCommand,
and closing the connection in the finally clause
Still, it is returning the following error everytime this sub is called:
Description:System.InvalidOperationException: Invalid attempt to call Read when reader is closed.
at System.Data.SqlClient.SqlDataReader.ReadInternal(Boolean setTimeout)
at System.Data.SqlClient.SqlDataReader.Read()
at System.Data.SqlClient.SqlCommand.CompleteExecuteScalar(SqlDataReader ds, Boolean returnSqlValue)
at System.Data.SqlClient.SqlCommand.ExecuteScalar()
Can Anyone help me figure out why?
Any help would be appreciated

Answer 1

Use the Using-statement instead and don't reuse the SqlConnection:
Public Function CheckSentToday(ByVal date1 As DateTime) As Boolean
Using cnSql = New SqlConnection("connection-string")
Using cmSql As New SqlCommand("Check_Today", cnSql)
cmSql.CommandType = CommandType.StoredProcedure
cmSql.Parameters.AddWithValue("#date1", String.Format("{0:yyyy-MM-dd}", date1))
Try
cnSql.Open()
If cmSql.ExecuteScalar IsNot Nothing Then
Return True
Else
Return False
End If
Catch ex As Exception
WriteToText("CheckSentToday: ", ex.ToString)
CheckSentToday = False
End Try
End Using
End Using
End Function