数据绑定计算字段 [英] DataBinding to Calculated Field

问题描述

我运行到哪里我想一个DataGrid的DataTextColumn绑定到计算字段的小问题。

I'm running into a small problem where I'm trying to bind a DataTextColumn of a DataGrid to a Calculated Field.

WPF

<DataGrid ItemsSource="{Binding Path=CurrentRoster, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" 
          AutoGenerateColumns="False" 
          AlternatingRowBackground="Gainsboro"  
          AlternationCount="2">
    <DataGrid.Columns>
    <DataGridComboBoxColumn Header="Student Enrolled"
                            ItemsSource="{Binding Source={StaticResource AvailableStudents}}"
                            SelectedItemBinding="{Binding Path=Student}">
    </DataGridComboBoxColumn>
    <DataGridTextColumn Header="Registration" Binding="{Binding Path=RegistrationCosts, StringFormat='{}{0:C}'}"/>
    <DataGridTextColumn Header="Lodging" Binding="{Binding Path=LodgingCosts, StringFormat='{}{0:C}'}"/>
    <DataGridTextColumn Header="Travel" Binding="{Binding Path=TravelCosts, StringFormat='{}{0:C}'}"/>
    <DataGridTextColumn Header="Dining" Binding="{Binding Path=DiningCosts, StringFormat='{}{0:C}'}"/>
    <DataGridTextColumn Header="Total Costs" IsReadOnly="True" Binding="{Binding Path=TotalCosts, StringFormat='{}{0:C}'}"/>
</DataGrid.Columns>

在哪里学生是一个小的添加实体对象。 TotalCosts是不是对数据库表的字段，所以我创建了一个局部类此。

Where Student is a Entity object with one small addition. TotalCosts isn't a field on the db tables, so I created a partial class for this.

public partial class Student
{
    public  Decimal TotalCosts
    {
        get { return (LodgingCosts + RegistrationCosts + TravelCosts + DiningCosts); }
    }
}

我遇到的问题是，TotalCosts是当你在其他任何领域的填不自动更新。我猜是因为它不是作为依赖属性中列出。我该如何解决这一对在没有设置属性？

The problem I'm experiencing is that TotalCosts is not automatically updating when you fill in any of the other fields. My guess it is because it is not listed as a dependency property. How do I resolve this for a property where there is no set ?

推荐答案

您可以致电 OnPropertyChanged（ TotalCosts）在 TotalCosts 在于，将刷新绑定

You can call OnPropertyChanged("TotalCosts") in the setters of each property that TotalCosts depends on, it will refresh the binding

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