从字符串“”到类型“布尔”的转换无效

我在 ASP.NET 登录表单的标题中收到错误消息，有谁知道我该如何解决它？非常感谢帮助

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click
  Dim conn As New MySqlConnection

  conn.ConnectionString = ("server=localhost;port=3307;user=user;password=password;database=DB;")

  Try

    Dim SQL As String = "select * from users3 where uname = '" & txtUName.Text & "' AND password = '" & txtPwd.Text & "'"

    conn.Open()

    Dim cmd As New MySqlCommand(SQL, conn)
    Dim reader As MySqlDataReader = cmd.ExecuteReader

        reader.Read()
        Dim isValidLogin As Boolean
        Boolean.TryParse(reader.GetValue(1), isValidLogin)

        If isValidLogin Then
            Session("UserName") = txtUName.Text
      Response.Redirect("REGISTERPROP.aspx")
    Else
      Response.Write("Invalid Login")
    End If

  Catch ex As Exception
    Response.Write("An Error Occurred: " & ex.Message.ToString())
  End Try
End Sub

Change:

Dim isValidLogin = reader.GetValue(1)

to:

Dim isValidLogin As Boolean
Boolean.TryParse(reader.GetValue(1), isValidLogin)