At first, if you want to go back to the previous activity in your dialogframent, you can try to call the
base.OnBackPressed(); in the
private void BtnLogOut1_Click(object sender, EventArgs e). In addition, maybe you need to call it twice, from dialog to dashboard activity and then the main activity.
Then if you want to exit the app, you can use the following code:
private void BtnExitapp1_Click(object sender, EventArgs e)
{
Android.OS.Process.KillProcess(Android.OS.Process.MyPid());
}