在项目中，由于使用到了活动积温运算，也就是指当日平均气温稳定上升到10℃以上时，大多数农作物才能活跃生长。把大于等于10℃持续期内的日平均气温累加起来，得到的气温总和，叫做活动积温。所以我决定采用dojo的原生仪表盘的图片素材进行封装，作出一个silverlight版本来。下面是其界面截图和具体的调用方法：
调用方法如下：
1: Data d = new Data();
2: d.Val = 40;
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4: var uc = new ChartControl(d);
5: Test.Children.Add(uc);
由于本控件做的比较仓促，所以XAML代码并未加以清理，还请各位看官凑合这看吧。
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2: xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
3: xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
4: xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
5: xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
6: xmlns:converter="clr-namespace:TinyFrame.Silverlight"
7: mc:Ignorable="d"
8: Loaded="UserControl_Loaded"
9: d:DesignHeight="248" d:DesignWidth="400">
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后台代码如下：
1: using System.Windows.Controls;
2: using System.ComponentModel;
3: using System.Windows.Threading;
4:
5: namespace TinyFrame.Silverlight
6: { 7: public partial class ChartControl : UserControl
8: { 9: public ChartControl(Data data)
10: { 11: InitializeComponent();
12: this.data = data;
13: Grid.DataContext = data;
14: }
15:
16: private Data data;
17: private DispatcherTimer timer;
18: private static double temp;
19: }
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21: public class Data:INotifyPropertyChanged
22: { 23: /*转30゜的角，表盘上的区间是 动了10
24: 0 刻度对应的角是 -150゜
25: 10 刻度对应的角是 -120゜
26: 20 刻度对应的角是 -90゜
27: ...
28: 100刻度对应的角是 150゜
29: 刻度数(x)转角度数(y): x = -150+3y;
30: 角度数(y)转刻度数(x): y = x/3 +50;
31: */
32: private double val = 0;
33: public double Val
34: { 35: get
36: { 37: return val;
38: }
39: set
40: { 41: if(val!=value)
42: { 43: preVal = val;
44:
45: val=value;
46: Notify("Val"); 47: }
48: }
49: }
50:
51: private double preVal;
52: public double PreVal
53: { 54: get
55: { 56: return preVal;
57: }
58: set
59: { 60: if (preVal != value)
61: { 62: preVal = value;
63: Notify("PreVal"); 64: }
65: }
66: }
67:
68: public event PropertyChangedEventHandler PropertyChanged;
69:
70: public void Notify(string propertyName)
71: { 72: if (PropertyChanged != null)
73: PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
74: }
75: }
76: }
由于用户输入的当前积温值（X）和刻度值（Y）有如下的对应关系：X=-150+3*Y，所以这里我们需要进行一下值的转换，就是让用户输入当前积温值的时候，能够自动转换为表盘需要转的度数，这里我们采用Value Converter来实现：
1: using System;
2: using System.Windows.Data;
3: using System.Globalization;
4:
5: namespace TinyFrame.Silverlight
6: { 7: public class RotationConverter:IValueConverter
8: { 9: public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
10: { 11: if (value != null)
12: return -150 + 3 * double.Parse(value.ToString());
13: return null;
14: }
15:
16: public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
17: { 18: return null;
19: }
20: }
21: }
在XAML中，我们这样使用，就可以了：
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最后附上代码下载：