just put SendKeys.Send("{RIGHT}") in function and call it in valuechange event for the datetimepiker,and in click event for button that used to add the data to the data base write dateTimePicker1.Focus(); and call the function again .:
private void dateTimePicker1_ValueChanged(object sender, EventArgs e)
{
DoTheStuff();
}
private void button1_Click(object sender, EventArgs e)
{
dateTimePicker1.Focus();
DoTheStuff();
}
private void DoTheStuff()
{
SendKeys.Send("{RIGHT}");
}