字符串属性和 Button.Content 的 WPF 绑定
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WPF binding of string property and Button.Content
提问by Begtostudy
I want to bind string property with Button.Content.
我想将字符串属性与 Button.Content 绑定。
But why it didn't work?
但为什么它不起作用？
The data class:
数据类：
namespace test4
{
public class Test : INotifyPropertyChanged
{
string _Text = "Begin";
public string Text
{
get{return _Text;}
protected set { _Text = value; }
}
public void Start()
{
Text = "Begin";
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(Text));
}
public void End()
{
Text = "End";
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(Text));
}
public event PropertyChangedEventHandler PropertyChanged;
}
}
The logical code:
逻辑代码：
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
test4.Test ttt = new test4.Test();
private void Window_Loaded(object sender, RoutedEventArgs e)
{
System.Windows.Data.CollectionViewSource testViewSource = ((System.Windows.Data.CollectionViewSource)(this.FindResource("testViewSource")));
testViewSource.Source = new object[]{ttt};
}
private void button1_Click(object sender, RoutedEventArgs e)
{
if (ttt.Text == "Begin")
ttt.End();
else
ttt.Start();
}
}
The XAML:
XAML：
<Window x:Class="test5.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525" mc:Ignorable="d" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:my="clr-namespace:test4" Loaded="Window_Loaded">
<Window.Resources>
<CollectionViewSource x:Key="testViewSource" d:DesignSource="{d:DesignInstance my:Test, CreateList=true}" />
</Window.Resources>
<Grid DataContext="{StaticResource testViewSource}">
<Button Content="{Binding Path=Text, Mode=OneWay, UpdateSourceTrigger=PropertyChanged}" Height="23" HorizontalAlignment="Left" Margin="158,95,0,0" Name="button1" VerticalAlignment="Top" Width="75" Click="button1_Click" />
</Grid>
</Window>
采纳答案by Nir
The quotes around Text in the call to the PropertyChangedEventArgs constructor are missing:
在对 PropertyChangedEventArgs 构造函数的调用中 Text 周围的引号丢失：
Text = "Begin";
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs("Text"));
回答by HCL
PropertyChangedwants to see the name of the property that has changed and not the value. Change the event invocation to:
PropertyChanged想要查看已更改的属性的名称而不是值。将事件调用更改为：
PropertyChanged(this, new PropertyChangedEventArgs("Text"));
and it will do the job. However I also would change the construction to
它会完成这项工作。但是，我也会将构造更改为
public string Text {
get{return _Text;}
protected set {
_Text = value;
if(null != PropertyChanged){
PropertyChanged(this,new PropertyChangedEventArgs("Text"));
}
}
}
and then dont call the PropertyChanged-event from Start and End.
然后不要从开始和结束调用 PropertyChanged 事件。
And to go even a step further, create invocation-methods like:
更进一步，创建调用方法，如：
protected virtual void OnPropertyChanged(string propertyName) {
OnPropertyChanged(new PropertyChangedEventArgs(propertyName));
}
protected virtual void OnPropertyChanged(PropertyChangedEventArgs e) {
if (null != PropertyChanged) {
PropertyChanged(this,e);
}
}
and then call them from your property-setter.
然后从您的属性设置器中调用它们。
回答by Begtostudy
First of all, I used objectdataproviding, but it is not the object "ttt", they are two different things.
首先，我使用了objectdataproviding，但它不是对象“ttt”，它们是两个不同的东西。
Second, PropertyChanged(this,new PropertyChangedEventArgs("Text"));"Text" is the name not the variable.
其次，PropertyChanged(this,new PropertyChangedEventArgs("Text"));“文本”是名称而不是变量。
So, the code is following, may be helpful to others.
因此，代码如下，可能对其他人有帮助。
The data class:
数据类：
namespace test3
{
public class Test : INotifyPropertyChanged
{
string _Text = "Begin";
public string Text
{
get{return _Text;}
protected set { _Text = value;
NotifyPropertyChanged("Text");
}
}
public void Start()
{
Text = "Begin";
}
public void End()
{
Text = "End";
}
public event PropertyChangedEventHandler PropertyChanged;
public void NotifyPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
}
The logical cs:
逻辑 cs：
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
button1.DataContext=ttt;
}
Test ttt = new Test();
private void button1_Click(object sender, RoutedEventArgs e)
{
if (ttt.Text == "Begin")
ttt.End();
else
ttt.Start();
}
}
}
The xaml:
xml：
<Window x:Class="test3.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:test3"
Title="MainWindow" Height="350" Width="525" >
<Grid>
<Button Content="{Binding Path=Text,UpdateSourceTrigger=PropertyChanged}" Height="23" HorizontalAlignment="Left" Margin="121,69,0,0" Name="button1" VerticalAlignment="Top" Width="75" Click="button1_Click" />
</Grid>
</Window>
回答by Faenrig
You need to use quotes around the property:
您需要在属性周围使用引号：
public void Start()
{
Text = "Begin";
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs("Text"));
}
I suggest to rather use the nameof()-method as you cannot rename the property while it's located between quotes:
我建议宁可使用 nameof() 方法，因为当属性位于引号之间时，您无法重命名该属性：
public void Start()
{
Text = "Begin";
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(nameof(Text)));
}
