вход в систему с помощью запроса select 1

Question

Я пытаюсь закодировать страницу входа, вот мой код:

      'login form code
Private Sub btnLogin_Click(sender As Object, e As EventArgs) Handles btnLogin.Click

        Dim username As String = txtUsername.Text.Trim
        Dim pwd As String = txtPassword.Text.Trim
        Dim insertQry As String = "select 1 from UserInfo where username = '" & username & "' and userpassword = '" & pwd & "'"  
        Dim res As Boolean = executeReader(insertQry)
End Sub

database module

Imports System.Data.SqlClient

Module DBconn
    Public conn_ As New SqlConnection("")   

    Public Function executeReader(ByVal query As String)
        Try
            Dim cmd As New SqlCommand(query, conn_)
            conn_.Open()
            Dim r2 As SqlDataReader = cmd.ExecuteReader()
            
            Return True
        Catch ex As Exception
            Return False
        End Try
    End Function

End Module

Мой вопрос: как выполнить проверку имени пользователя и пароля с помощью запроса select 1?