你如何将两个文本框的内容添加在一起并显示在一个文本块中答案

【问题标题】：How do you to Add The Contents of Two TextBoxes Together and Display in a TextBlock你如何将两个文本框的内容添加在一起并显示在一个文本块中
【发布时间】：2014-08-13 00:53:24
【问题描述】：

我正在动态创建两个文本框和一个文本块。用户首先单击添加一行控件的按钮，然后在每个文本框中输入数字。给定行的两个框的总和将显示在文本块中。

这是 XAML。

    <Window x:Class="ModelBuilder_080614.MainWindow"
            xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
            xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
            xmlns:local="clr-namespace:ModelBuilder_080614"
            Title="MainWindow" Height="350" Width="525">
        <Window.DataContext>
            <!-- this is a comment -->
            <local:MainWindowViewModel />
        </Window.DataContext>
        <Canvas>
            <Button Canvas.Top="21" Canvas.Left="20" Content="Add TextBox" Command="{Binding TestCommand}"/>
            <ItemsControl  Canvas.Top="50" Canvas.Left="50" ItemsSource="{Binding SomeCollection}">
                <ItemsControl.ItemTemplate>
                    <DataTemplate>
                        <Grid >
                            <Grid.RowDefinitions>
                                <RowDefinition Height="Auto"/>
                                <RowDefinition Height="Auto"/>
                            </Grid.RowDefinitions>
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition Width="Auto"/>
                                <ColumnDefinition Width="Auto"/>
                                <ColumnDefinition Width="Auto"/>
                            </Grid.ColumnDefinitions>
                            <TextBox Grid.Column="0" Grid.Row="0" Text="{Binding Path=.}"/>
                            <TextBox Grid.Column="1" Grid.Row="0"   Name="Bench" Text="{Binding Path=.}"/>
                            <TextBlock Grid.Column="2" Grid.Row="0"  Text="{Binding <!-- I'm LOST -->}"/>
<!-- I want this TextBlock to sum the Two TextBlocks -->
                        </Grid>
                    </DataTemplate>
                </ItemsControl.ItemTemplate>
            </ItemsControl>
        </Canvas>
    </Window>

这是我的 C# 模型和视图模型。

using System;
using System.ComponentModel;
using System.Windows.Input;
using System.Collections.ObjectModel;
using System.Windows.Controls;
using System.Windows.Data;
using MicroMvvm;

namespace ModelBuilder_080614
{

    public class MainWindowViewModel
    {
        public ObservableCollection<Model> SomeCollection { get; set; }

        public ICommand TestCommand { get; private set; }

        public MainWindowViewModel()
        {
            SomeCollection = new ObservableCollection<Model>();
            TestCommand = new RelayCommand<object>(CommandMethod);
        }

        private void CommandMethod(object parameter)
        {
            SomeCollection.Add(new Model());
        }
    }

    public class Model : INotifyPropertyChanged
    {
        double _actual;
        double _bench;
        double _active;

        public double Actual
        {
            get { return _actual; }
            set { _actual = value; }
        }

        public double Bench
        {
            get { return _bench; }
            set { _bench = value; }
        }

        public double Active
        {
            get { return _active; }
            set { _active = Actual - Bench; }

        }


        public event PropertyChangedEventHandler PropertyChanged;
        protected void OnPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }
}

如何绑定文本框的内容以在TextBlock中显示它们的总和？

【问题讨论】：

标签： c# wpf xaml

【解决方案1】：

绑定到 ViewModel 中的属性：（我删除了网格设置以使示例更清晰）

<TextBox Text="{Binding Path=Actual, UpdateSourceTrigger=PropertyChanged}" />
<TextBox Text="{Binding Path=Bench, UpdateSourceTrigger=PropertyChanged" />
<TextBlock Text="{Binding Path=Active" />

然后，当您的值发生变化时，请在“活动”属性上发出通知，以便它更新。您只需要在“Active”属性上添加一个“getter”...当您调用 OnPropertyChanged() 时，它会执行计算并为您更新字段。

double _actual;
double _bench;

public double Actual
{
    get { return _actual; }
    set
    {
        _actual = value;
        OnPropertyChanged("Active");
    }
}

public double Bench
{
    get { return _bench; }
    set
    {
        _bench = value;
        OnPropertyChanged("Active");
    }
}

public double Active
{
    get { return Actual - Bench; }
}

【讨论】：