在WPF MVVM模式开发中，实现INotifyPropertyChanged的ViewModel是非常重要且常见的类：
public class MainViewModel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propertyName)
{
if (this.PropertyChanged != null)
this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
在类里，需要响应变化的属性都需要在Setter里调用属性变化的方法：
private string _appName;
public string AppName
{
get
{
return _appName;
}
set
{
if (_appName == value)
return;
_appName = value;
OnPropertyChanged(nameof(AppName));
}
}
这样的写法，一个两个属性还好，在有很多属性的情况下，就显得有一些繁杂，今天要介绍一款开源的工具就是为了解决这个问题。
Fody/PropertyChanged
使用方法
通过Nuget安装
PM> Install-Package PropertyChanged.Fody安装完成后，会在项目中，添加FodyWeavers.xml文件，这是Fody的配置文件，详细可以参考 Fody
<?xml version="1.0" encoding="utf-8"?>
<Weavers>
<PropertyChanged />
</Weavers>
说明
- 程序中的代码：
[ImplementPropertyChanged]
public class Person
{
public string GivenNames { get; set; }
public string FamilyName { get; set; }
public string FullName
{
get
{
return string.Format("{0} {1}", GivenNames, FamilyName);
}
}
}
或者
public class MainViewModel : INotifyPropertyChanged
{
public string GivenNames { get; set; }
public string FamilyName { get; set; }
public string FullName
{
get
{
return string.Format("{0} {1}", GivenNames, FamilyName);
}
}
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propertyName)
{
if (this.PropertyChanged != null)
this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
- 编译后对应的
public class Person : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
string givenNames;
public string GivenNames
{
get { return givenNames; }
set
{
if (value != givenNames)
{
givenNames = value;
OnPropertyChanged("GivenNames");
OnPropertyChanged("FullName");
}
}
}
string familyName;
public string FamilyName
{
get { return familyName; }
set
{
if (value != familyName)
{
familyName = value;
OnPropertyChanged("FamilyName");
OnPropertyChanged("FullName");
}
}
}
public string FullName
{
get
{
return string.Format("{0} {1}", GivenNames, FamilyName);
}
}
public virtual void OnPropertyChanged(string propertyName)
{
var propertyChanged = PropertyChanged;
if (propertyChanged != null)
{
propertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}