C# 如何在WPF中使用DelegateCommand从列表中填充列表框?
我在填写列表框时遇到了一个问题。 我的xaml文件中有一个按钮:C# 如何在WPF中使用DelegateCommand从列表中填充列表框?,c#,wpf,listbox,viewmodel,delegatecommand,C#,Wpf,Listbox,Viewmodel,Delegatecommand,我在填写列表框时遇到了一个问题。 我的xaml文件中有一个按钮: <Button Content="Show" Command="{Binding ShowSongsBy}" ... > 当我按下按钮时,会发生以下情况(同样在ViewModel中): 我看到了我希望在列表框中看到的内容:“1”、“2”和“Test1” 如果我只想列出“1”和“2”,我该怎么办 我的DelegateCommand类: class DelegateCommand : ICommand {
<Button Content="Show" Command="{Binding ShowSongsBy}" ... >
当我按下按钮时,会发生以下情况(同样在ViewModel中):
我看到了我希望在列表框中看到的内容:“1”、“2”和“Test1”
如果我只想列出“1”和“2”,我该怎么办
我的DelegateCommand类:
class DelegateCommand : ICommand
{
private Action<object> execute;
private Func<object, bool> canExecute;
public event EventHandler CanExecuteChanged
{
add { CommandManager.RequerySuggested += value; }
remove { CommandManager.RequerySuggested -= value; }
}
public DelegateCommand(Action<object> execute, Func<object, bool> canExecute = null)
{
this.execute = execute;
this.canExecute = canExecute;
}
public bool CanExecute(object parameter)
{
return this.canExecute == null || this.canExecute(parameter);
}
public void Execute(object parameter)
{
this.execute(parameter);
}
}
class DelegateCommand:ICommand
{
私人行动执行;
私人职能执行;
公共事件事件处理程序CanExecuteChanged
{
添加{CommandManager.RequerySuggested+=value;}
删除{CommandManager.RequerySuggested-=value;}
}
公共DelegateCommand(执行操作,Func canExecute=null)
{
this.execute=execute;
this.canExecute=canExecute;
}
公共布尔CanExecute(对象参数)
{
返回this.canExecute==null | | this.canExecute(参数);
}
public void Execute(对象参数)
{
执行(参数);
}
}
谢谢。使用
可观察收集
而不是列表
private observeCollection\u sortedList;
公共可观察收集分类列表VM
{
获取=>\u排序列表;
设置
{
_sortedList=值;
onPropertyChanged();
}
}
。。。做你想用它做的事。与使用列表
操作的方式相同
ListBox
将在您对集合进行任何更改时动态更新其布局
private List<string> _sortedList;
public List<string> SortedListVM
{
set
{
_sortedList = value;
onPropertyChanged();
}
get { return _sortedList; }
}
public event PropertyChangedEventHandler PropertyChanged;
public void onPropertyChanged([CallerMemberName]string prop = "")
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(prop));
}
public ICommand ShowSongsBy
{
get
{
return new DelegateCommand((obj) =>
{
SortedListVM = new List<string>();
List<string> testlist = new List<string>();
testlist.Add("1");
testlist.Add("2");
foreach (string i in testlist)
{
SortedListVM.Add(i);
}
});
}
}
public ICommand ShowSongsBy
{
...
foreach (string i in testlist)
{
SortedListVM.Add(i);
}
SortedListVM.Add("Test1");
...
class DelegateCommand : ICommand
{
private Action<object> execute;
private Func<object, bool> canExecute;
public event EventHandler CanExecuteChanged
{
add { CommandManager.RequerySuggested += value; }
remove { CommandManager.RequerySuggested -= value; }
}
public DelegateCommand(Action<object> execute, Func<object, bool> canExecute = null)
{
this.execute = execute;
this.canExecute = canExecute;
}
public bool CanExecute(object parameter)
{
return this.canExecute == null || this.canExecute(parameter);
}
public void Execute(object parameter)
{
this.execute(parameter);
}
}