How to select all text in Winforms NumericUpDown upon tab in?

I was looking around i had the same issue and this Works for me, first select the Item and the second one selects the Text, hope it helps in future

myNumericUpDown.Select();
 myNumericUpDown.Select(0, myNumericUpDown.Value.ToString().Length);

I wanted to add to this for future people who have been search for Tab and Click.

Jon B answer works perfect for Tab but I needed to modify to include click

Below will select the text if you tab in or click in. If you click and you enter the box then it will select the text. If you are already focused on the box then the click will do what it normally does.

    bool selectByMouse = false;

    private void quickBoxs_Enter(object sender, EventArgs e)
    {
        NumericUpDown curBox = sender as NumericUpDown;
        curBox.Select();
        curBox.Select(0, curBox.Text.Length);
        if (MouseButtons == MouseButtons.Left)
        {
            selectByMouse = true;
        }
    }

    private void quickBoxs_MouseDown(object sender, MouseEventArgs e)
    {
        NumericUpDown curBox = sender as NumericUpDown;
        if (selectByMouse)
        {
            curBox.Select(0, curBox.Text.Length);
            selectByMouse = false;
        }
    }

You can use this for multiple numericUpDown controls. Just need to set the Enter and MouseDown Events

private void NumericUpDown1_Enter(object sender, EventArgs e)
{
    NumericUpDown1.Select(0, NumericUpDown1.Text.Length);
}

(Note that the Text property is hidden in Intellisense, but it's there)