原文:

在实际工作中，WPF提供的控件并不能完全满足不同的设计需求。这时，需要我们设计自定义控件。

这里LZ总结一些自己的思路，特性如下：

• Coupling
• UITemplate
• Behaviour
• Function Package

下面举例说说在项目中我们经常用到调音台音量条，写一个自定义控件模拟调音台音量条。

自定义控件SingnalLight,实现功能

• 接收来自外部的范围0~100的数值
• 实时显示接收数值
• 数值范围0~50显示绿色，50~85显示黄色，85~100显示红色，没有数值显示褐色
• 可在父控件上拖拽该控件

 

public class SingnalLight : ContentControl {        public int ValueA {            get { return (int)GetValue(ValueAProperty); }            set { SetValue(ValueAProperty, value); }        }            public SingnalLight() {            this.AllowDrop = true;        }        static SingnalLight() {            DefaultStyleKeyProperty.OverrideMetadata(typeof(SingnalLight), new FrameworkPropertyMetadata(typeof(SingnalLight)));        }    }

ValueA为接受外部数值的属性

2.复写控件UITemplate

1  

 

3.接受值判断，SingnalLight通过实现IValueConverter和Override Arrange & Measure Methods，实现了UI呈现的绑定，

1     public class SingnalLightStatusConverter : IValueConverter { 2         public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { 3             SolidColorBrush result = Brushes.Transparent; 4             if (value.GetType() == typeof(int)) { 5                 var color = System.Convert.ToInt32(value); 6                 if (color < 50) result = Brushes.Green; 7                 else if (color < 85 && color >= 50) result = Brushes.Yellow; 8                 else if (color <= 100 && color >= 85) result = Brushes.Red; 9                 else result = Brushes.Gray;10             }11             return result;12         }13 14         public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) {15             throw new NotImplementedException();16         }17     }18 19     public class SingnalLightValueConverter : IMultiValueConverter {20         public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture) {21             double result = 0;22             if (values[0].GetType() == typeof(int) && values[1].GetType() == typeof(double)) {23                 result = (double)values[1] / 100 * System.Convert.ToDouble(values[0]);24             }25             return result;26         }27 28         public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture) {29             throw new NotImplementedException();30         }31     }

1         protected override Size MeasureOverride(Size constraint) {2             if (ActualHeight > 0) LightHeight = ActualHeight * .7;3             return base.MeasureOverride(constraint);4         }5 6         protected override Size ArrangeOverride(Size arrangeBounds) {7             return base.ArrangeOverride(arrangeBounds);8         }

4.控件支持拖拽，覆写MouseDown,MouseMove,MouseUp方法。这样写的好处是，如果在父控件的事件中实现Drag，父控件如果有多个对象，这样逻辑会十分混乱。

1         protected override void OnMouseMove(MouseEventArgs e) { 2             base.OnMouseMove(e); 3             if (e.LeftButton == MouseButtonState.Pressed) { 4                 _currentPoint = e.GetPosition(this); 5                 X += _currentPoint.X - _startPoint.X; 6                 Y += _currentPoint.Y - _startPoint.Y; 7             } 8         } 9 10         protected override void OnMouseDown(MouseButtonEventArgs e) {11             base.OnMouseDown(e);12             _startPoint = e.GetPosition(this);13             this.CaptureMouse();14         }15 16         protected override void OnMouseUp(MouseButtonEventArgs e) {17             base.OnMouseUp(e);18             this.ReleaseMouseCapture();19         }

 

 

自定义控件系列博文链接：