Chrome有点类似于用GDI+画图一般,除了模板,也可以使用DrawingContext对象来画图.

WPF内置的很多控件都是如此实现的,虽然麻烦了一些,可能是为了提升性能考虑.

其方式与定义样式模板差不多,只不过换成代码形式了.

1.先定义控件不同状态下的颜色,如

private static SolidColorBrush CommonDisabledBackgroundOverlay {get {if (commonDisabledBackgroundOverlay == null) {lock (resourceAccess) {if (commonDisabledBackgroundOverlay == null) {SolidColorBrush brush = new SolidColorBrush(Color.FromRgb(0xf4, 0xf4, 0xf4));brush.Freeze();commonDisabledBackgroundOverlay = brush;}}}return commonDisabledBackgroundOverlay;}
}

2.定义控件样式状态

private Brush BackgroundOverlay {get {if (!base.IsEnabled) {return CommonDisabledBackgroundOverlay;}if (!this.Animates) {if (this.RenderPressed) {return CommonPressedBackgroundOverlay;}if (this.RenderMouseOver) {return CommonHoverBackgroundOverlay;}return null;}        return null; }
}

3.在OnRender方法中呈现样式

private void DrawBackground(DrawingContext dc, ref Rect bounds)
{if (base.IsEnabled || Corners.None != this.RoundCorners){Brush background = this.Background;if (background == null) background = this.BackgroundOverlay;if ((bounds.Width > 4.0) && (bounds.Height > 4.0)){Rect rectangle = new Rect(bounds.Left + 1.0, bounds.Top + 1.0, bounds.Width - 2.0, bounds.Height - 2.0);if (background != null){if (!this.RenderTransparentBackground || this.RenderDefaulted || this.RenderMouseOver || this.RenderPressed)dc.DrawRectangle(background, null, rectangle);elsedc.DrawRectangle(Brushes.Transparent, null, rectangle);}}}
}

现在为止一个背景色就设置好了,从这里回头看Border容器,也是采用用样的做法,WPF内置的Shape也是如此.

之前感觉比较困惑,Shape的呈现可以理解,Button的呈现还无法理解.
内置的Button使用了ButtonChrome,CheckBox使用了BulletChrome.估计其他控件也是如此.所以所有的控件还是一样,都是一点一滴画出来的.