将数据从属性绑定到文本块 - MVVM Light 和 WPF
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Bind Data From Property to Textblock - MVVM Light and WPF
提问by user2975939
I have a textblock in WPF which is bound to a property in my ViewModel class. On click of a button I wish to modify the property and expect the same to be reflected in my textblock. I want all these to be done purely using MVVM (MVVMLight). I am using MMVM light and VS 2012. Challenges- On button click the changes are not being reflected. Though the program execution is going inside the property , changes are not being made.
我在 WPF 中有一个文本块，它绑定到我的 ViewModel 类中的一个属性。单击按钮时，我希望修改该属性，并希望在我的文本块中反映相同的内容。我希望所有这些都完全使用 MVVM (MVVMLight) 完成。我正在使用 MMVM light 和 VS 2012。挑战 - 单击按钮时，更改未得到反映。尽管程序在属性内部执行，但并未进行更改。
Please Help !!
请帮忙 ！！
Program- View:
程序视图：
<Window x:Class="MvvmLight1_Trail.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:ignore="http://www.ignore.com"
mc:Ignorable="d ignore"
Height="500"
Width="500"
Title="MVVM Light Application"
DataContext="{Binding Main, Source={StaticResource Locator}}">
<Grid x:Name="LayoutRoot">
<TextBlock FontSize="34"
Text="{Binding Path=MyText,UpdateSourceTrigger=Default, Mode=TwoWay}"
VerticalAlignment="Center"
HorizontalAlignment="Center"
TextWrapping="Wrap" />
<Button Width="100" Height="100" Command="{Binding PressCommand}" Margin="198.985,277.537,193.014,92.462" Content="Press Me"/>
</Grid>
View Model
查看模型
using GalaSoft.MvvmLight;
using GalaSoft.MvvmLight.Command;
using MvvmLight1_Trail.Model;
using System.ComponentModel;
using System.Threading;
namespace MvvmLight1_Trail.ViewModel
{
public class MainViewModel : ViewModelBase
{
public RelayCommand PressCommand { get; private set; }
Thread t;
private string _welcomeTitle = string.Empty;
public string MyText
{
get
{
return _welcomeTitle;
}
set
{
if (_welcomeTitle == value)
{
return;
}
_welcomeTitle = value;
RaisePropertyChanged(MyText);
}
}
/// <summary>
/// Initializes a new instance of the MainViewModel class.
/// </summary>
public MainViewModel()
{
PressCommand = new RelayCommand(() => MyFunc());
myfunc();
}
private void MyFunc()
{
this.MyText = "Hi2";
}
private void myfunc()
{
this.MyText = "Hello";
this.MyText = "Hi";
}
}
}
回答by Rohit Vats
Replace
代替
RaisePropertyChanged(MyText);
RaisePropertyChanged(MyText);
to
到
RaisePropertyChanged("MyText");
RaisePropertyChanged("MyText");
PropertyChanged event should be raised on property name and not on property value.
PropertyChanged 事件应该在属性名称而不是属性值上引发。
回答by arpl
Already answered by @Rohit Vats. You can also call RaisePropertyChanged like, RaisePropertyChanged( () => MyText)to ease renaming later.
@Rohit Vats 已经回答了。您还可以调用 RaisePropertyChanged 之类的方法，RaisePropertyChanged( () => MyText)以便稍后重命名。
回答by barakcaf
Late to the game but:
比赛迟到了，但是：
in new C# 6 you can also use nameof like this:
在新的 C# 6 中，您还可以像这样使用 nameof：
RaisePropertyChanged(nameof(MyText))
