WPF实现强大的动态公式计算

数据库可以定义表不同列之间的计算公式，进行自动公式计算，但如何实现行上的动态公式计算呢？行由于可以动态扩展，在某些应用场景下将能很好的解决实际问题。

1、VS2012新建一个WPF应用程序WpfApp_DynCalc，并添加一个类DynCalc.cs，如下图：

 

2、编辑MainWindow.xaml，代码如下：

  1 <Window x:Class="WpfApp_DynCalc.MainWindow"
  2         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  3         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  4         Title="WPF动态计算示例" Height="350" Width="525">
  5     <Grid>
  6         <Grid.Resources>
  7         <Style TargetType="DataGrid">
  8             
  9             <Setter Property="CanUserResizeColumns" Value="false"/>
 10             <Setter Property="Background" Value="#E6DBBB" />
 11             <Setter Property="BorderBrush" Value="#d6c79b" />
 12             <Setter Property="HorizontalGridLinesBrush">
 13                 <Setter.Value>
 14                     <SolidColorBrush Color="#d6c79b"/>
 15                 Setter.Value>
 16             Setter>
 17             <Setter Property="VerticalGridLinesBrush">
 18                 <Setter.Value>
 19                     <SolidColorBrush Color="#d6c79b"/>
 20                 Setter.Value>
 21             Setter>
 22         Style>
 23 
 24         
 25         
 32 
 33         <Style TargetType="DataGridColumnHeader">
 34             <Setter Property="SnapsToDevicePixels" Value="True" />
 35             <Setter Property="MinWidth" Value="0" />
 36             <Setter Property="MinHeight" Value="28" />
 37             <Setter Property="Foreground" Value="#323433" />
 38             <Setter Property="FontSize" Value="14" />
 39             <Setter Property="Cursor" Value="Hand" />
 40             <Setter Property="Template">
 41                 <Setter.Value>
 42                     <ControlTemplate TargetType="DataGridColumnHeader">
 43                         <Border x:Name="BackgroundBorder" BorderThickness="0,1,0,1" 
 44                              BorderBrush="#e6dbba" 
 45                               Width="Auto">
 46                             <Grid >
 47                                 <Grid.ColumnDefinitions>
 48                                     <ColumnDefinition Width="*" />
 49                                 Grid.ColumnDefinitions>
 50                                 <ContentPresenter  Margin="0,0,0,0" VerticalAlignment="Center" HorizontalAlignment="Center"/>
 51                                 <Path x:Name="SortArrow" Visibility="Collapsed" Data="M0,0 L1,0 0.5,1 z" Stretch="Fill"  Grid.Column="2" Width="8" Height="6" Fill="White" Margin="0,0,50,0" 
 52                             VerticalAlignment="Center" RenderTransformOrigin="1,1" />
 53                                 <Rectangle Width="1" Fill="#d6c79b" HorizontalAlignment="Right" Grid.ColumnSpan="1" />
 54                                 
 56                             Grid>
 57                         Border>
 58                     ControlTemplate>
 59                 Setter.Value>
 60             Setter>
 61             <Setter Property="Height" Value="25"/>
 62         Style>
 63         
 64         
 65         <Style  TargetType="DataGridRow">
 66             <Setter Property="Background" Value="#F2F2F2" />
 67             <Setter Property="Height" Value="25"/>
 68             <Setter Property="Foreground" Value="Black" />
 69             <Style.Triggers>
 70                 
 71                 <Trigger Property="AlternationIndex" Value="0" >
 72                     <Setter Property="Background" Value="#e7e7e7" />
 73                 Trigger>
 74                 <Trigger Property="AlternationIndex" Value="1" >
 75                     <Setter Property="Background" Value="#f2f2f2" />
 76                 Trigger>
 77 
 78                 <Trigger Property="IsMouseOver" Value="True">
 79                     <Setter Property="Background" Value="LightGray"/>
 80                     
 81                 Trigger>
 82 
 83                 <Trigger Property="IsSelected" Value="True">
 84                     <Setter Property="Foreground" Value="Black"/>
 85                 Trigger>
 86             Style.Triggers>
 87         Style>
 88 
 89         
 90         <Style TargetType="DataGridCell">
 91             <Setter Property="Template">
 92                 <Setter.Value>
 93                     <ControlTemplate TargetType="DataGridCell">
 94                         <TextBlock TextAlignment="Center" VerticalAlignment="Center"  >
 95                            <ContentPresenter />
 96                         TextBlock>
 97                     ControlTemplate>
 98                 Setter.Value>
 99             Setter>
100             <Style.Triggers>
101                 <Trigger Property="IsSelected" Value="True">
102                     
104                     <Setter Property="Foreground" Value="Black"/>
105                 Trigger>
106             Style.Triggers>
107         Style>
108         Grid.Resources>
109 
110 
111         <DataGrid  Name="dgrid"   HorizontalAlignment="Left" Margin="10,10,0,0" VerticalAlignment="Top" Height="256" Width="498"  AutoGenerateColumns="False" >
112             <DataGrid.Columns>
113                 <DataGridTextColumn  Header="指标" Binding="{Binding Zb}" Width="118"/>
114                 <DataGridTextColumn  Header="值" Binding="{Binding Value}" Width="100"/>
115                 <DataGridTextColumn  Header="公式" Binding="{Binding Formula}" Width="188"/>
116             DataGrid.Columns>
117         DataGrid>
118         <Button Content="计 算" HorizontalAlignment="Left" Margin="419,281,0,0" VerticalAlignment="Top" Width="85" Click="Button_Click_1" Height="28" />
119         <TextBlock Name="lblResult" HorizontalAlignment="Left" Margin="28,281,0,0" TextWrapping="Wrap" Text="" VerticalAlignment="Top"/>
120 
121     Grid>
122 Window>

3、编辑后台文件MainWindow.xaml.cs，代码如下：

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Threading.Tasks;
 6 using System.Windows;
 7 using System.Windows.Controls;
 8 using System.Windows.Data;
 9 using System.Windows.Documents;
10 using System.Windows.Input;
11 using System.Windows.Media;
12 using System.Windows.Media.Imaging;
13 using System.Windows.Navigation;
14 using System.Windows.Shapes;
15 
16 using System.Collections.ObjectModel;
17 namespace WpfApp_DynCalc
18 {
19     /// 

20     /// MainWindow.xaml 的交互逻辑
21     /// 
22     public partial class MainWindow : Window
23     {
24         public MainWindow()
25         {
26             InitializeComponent();
27 
28           
29             ObservableCollection ofs = new ObservableCollection();
30             ofs.Add(new Dynformula { Zb = "A", Value = "1", Formula = "" });
31             ofs.Add(new Dynformula { Zb = "B", Value = "2", Formula = "2*A+1" });
32             ofs.Add(new Dynformula { Zb = "C", Value = "3", Formula = "B*B" });
33             ofs.Add(new Dynformula { Zb = "D", Value = "4", Formula = "C-2" });
34             ofs.Add(new Dynformula { Zb = "Z", Value = "5", Formula = "D+C" });
35             this.dgrid.ItemsSource = ofs;
36          
37          
38         }
39 
40         private void Button_Click_1(object sender, RoutedEventArgs e)
41         {
42             this.lblResult.Text = "计算...";
43              this.dgrid.ItemsSource=   DynCalc.CalcScript(ref this.dgrid);
44              this.lblResult.Text = "计算完成!";
45           
46         }
47     }
48 
49     public class Dynformula
50     {
51         private string zb;
52 
53         public string Zb
54         {
55             get { return zb; }
56             set { zb = value; }
57         }
58         private string value;
59 
60         public string Value
61         {
62             get { return this.value; }
63             set { this.value = value; }
64         }
65         private string formula;
66 
67         public string Formula
68         {
69             get { return formula; }
70             set { formula = value; }
71         }
72 
73     }
74 }

3、编辑类DynCalc.cs，代码如下：

  1 using System;
  2 using System.Collections.Generic;
  3 using System.Linq;
  4 using System.Text;
  5 using System.Threading.Tasks;
  6 
  7 namespace WpfApp_DynCalc
  8 {
  9 using System.Collections.ObjectModel;
 10 using System.Windows; 
 11 using System.Windows.Controls;
 12 using System.Reflection; 
 13 using System.Globalization; 
 14 using Microsoft.CSharp;
 15 using System.CodeDom; 
 16 using System.CodeDom.Compiler;
 17    public static class DynCalc
 18     {
 19 
 20        public static ObservableCollection CalcScript(ref DataGrid dgrid)
 21        {
 22          
 23            CSharpCodeProvider objCSharpCodePrivoder = new CSharpCodeProvider();     
 24            ICodeCompiler objICodeCompiler = objCSharpCodePrivoder.CreateCompiler();
 25            CompilerParameters objCompilerParameters = new CompilerParameters();
 26            objCompilerParameters.ReferencedAssemblies.Add("System.dll");
 27            objCompilerParameters.GenerateExecutable = false;
 28            objCompilerParameters.GenerateInMemory = true;
 29            CompilerResults cr = objICodeCompiler.CompileAssemblyFromSource(objCompilerParameters, GenerateCode(ref dgrid));
 30            if (cr.Errors.HasErrors)
 31            {
 32                Console.WriteLine("编译错误：");
 33                foreach (CompilerError err in cr.Errors)
 34                {
 35                    Console.WriteLine(err.ErrorText);
 36                }
 37                return null;
 38            }
 39            else
 40            {
 41                // 通过反射，调用实例
 42                Assembly objAssembly = cr.CompiledAssembly;
 43                object objDynCalc = objAssembly.CreateInstance("DynamicCodeGenerate.RunScript");
 44                //MethodInfo objMI = objHelloWorld.GetType().GetMethod("OutPut");
 45                //Console.WriteLine(objMI.Invoke(objHelloWorld, null));
 46 
 47                ObservableCollection ofsnew = new ObservableCollection();
 48                //循环datagrid进行公式计算并赋值
 49                for (int i = 0; i < dgrid.Items.Count; i++)
 50                {
 51                    Dynformula item = dgrid.Items[i] as Dynformula;
 52                    if (item == null)
 53                    {
 54                        break;
 55                    }
 56                    string zb = item.Zb;
 57                    PropertyInfo pinfo = objDynCalc.GetType().GetProperty(zb);
 58                    if (pinfo != null && pinfo.CanRead)                   {
 59                        //获取属性get值
 60                        object obj_Name = pinfo.GetValue(objDynCalc, null);
 61                      //  item.Value = obj_Name.ToString();
 62                        ofsnew.Add(new Dynformula { Zb = item.Zb, Value = obj_Name.ToString(), Formula = item.Formula});
 63                    }
 64                }
 65                return ofsnew;
 66            }
 67        }
 68        /// 

 69        /// 计算逻辑C#脚本动态构建
 70        /// 
 71        /// 存有指标以及指标计算公式的datagrid
 72        /// C#脚本
 73         static string GenerateCode(ref DataGrid dgrid)
 74         {
 75             StringBuilder sb = new StringBuilder();
 76             StringBuilder sb构建函数内容 = new StringBuilder();
 77             sb.Append("using System;");
 78             sb.Append(Environment.NewLine);
 79             sb.Append("namespace DynamicCodeGenerate");
 80             sb.Append(Environment.NewLine);
 81             sb.Append("{");
 82             sb.Append(Environment.NewLine);
 83             sb.Append("    public class RunScript");
 84             sb.Append(Environment.NewLine);
 85             sb.Append("    {");
 86             //------------------------------------------------------------
 87             for(int i=0;i)
 88             {
 89                 Dynformula item = dgrid.Items[i] as Dynformula;
 90                 if (item == null)
 91                 {
 92                     break;
 93                 }
 94                 string zb = item.Zb;
 95                 sb.Append(Environment.NewLine);
 96                 sb.AppendFormat("        public double _{0};", item.Zb);
 97                 sb.Append(Environment.NewLine);
 98                 sb.AppendFormat("        public double {0}",item.Zb);
 99                 sb.Append(Environment.NewLine);
100                 sb.Append("        {");
101                 sb.Append(Environment.NewLine);
102               
103                 if (item.Formula.Trim() != "")
104                 {
105                     sb.Append("             set{ "+item.Zb+"=value;}" );
106                     sb.Append(Environment.NewLine);
107                     sb.Append("             get{return "+ item.Formula + ";}");
108                 }
109                 else
110                 {
111                     sb.Append("             set{ _" + item.Zb + "=value;}");               
112                     sb.Append(Environment.NewLine);
113                     sb.Append("             get{return  _"+item.Zb+";} ");
114                     sb.Append(Environment.NewLine);
115                     sb构建函数内容.Append("       _" + item.Zb + "=" + item.Value);
116                 }
117                 sb.Append(Environment.NewLine);
118                 sb.Append("        }");
119                 sb.Append(Environment.NewLine);
120             }         
121             //--------------------------------------------
122             //构造函数进行赋值
123             sb.Append(Environment.NewLine);
124             sb.Append("        public  RunScript()");
125             sb.Append(Environment.NewLine);
126             sb.Append("        {");
127             sb.Append(Environment.NewLine);
128             sb.AppendFormat("            {0};",sb构建函数内容.ToString());
129             sb.Append(Environment.NewLine);
130             sb.Append("        }");
131             sb.Append(Environment.NewLine);
132 
133             //----------------------------------------------
134             sb.Append(Environment.NewLine);
135             sb.Append("        public string OutPut()");
136             sb.Append(Environment.NewLine);
137             sb.Append("        {");
138             sb.Append(Environment.NewLine);
139             sb.Append("             return \"Hello world!\";");
140             sb.Append(Environment.NewLine);
141             sb.Append("        }");
142             //-----------------------------------------
143             sb.Append(Environment.NewLine);
144             sb.Append("    }");
145             sb.Append(Environment.NewLine);
146             sb.Append("}");
147 
148             string code = sb.ToString();
149             Console.WriteLine(code);
150             return code;
151         }
152 
153     }
154 }

4、运行程序，其中值列的值为初始值，点击计算后会根据公式列配置进行动态计算，初始化界面如下:

 5、点击计算后界面如下：

可见现在的值是根据公式配置进行动态计算的。当然代码经过扩展还可以支持函数和简单的逻辑判断，如if ...else等。实现更强大的逻辑处理。