(WPF) Grid渐入渐出效果

//渐入

            DoubleAnimation dLoginFadeIn = new DoubleAnimation(0, 1, new Duration(TimeSpan.FromSeconds(1)));
            this.Grid_Login.BeginAnimation(UIElement.OpacityProperty, dLoginFadeIn);

//渐出

                DoubleAnimation dLoginFadeOut = new DoubleAnimation(1, 0, new Duration(TimeSpan.FromSeconds(1)));
                this.Grid_Login.BeginAnimation(UIElement.OpacityProperty, dLoginFadeOut);