我做:命令模式如何工作?
<Button
Style="{StaticResource buttonstyle}"
HorizontalAlignment="Left" Margin="12,21,10,0"
VerticalAlignment="Top" Height="78" Width="83"
BorderThickness="2" Content="add event"
Command="{Binding NewEvent}"
CommandParameter="This is the report."
>
</Button>
其中的命令是:
public class StringDelegateCommand : ICommand
{
//methodes without return value
Action<string> m_ExecuteTargets = delegate { };
//methodes without parmtters inside
Func<bool> m_CanExecuteTargets = delegate { return false; };
//the value whom allows execution
bool m_Enabled = false;
#region ICommand Members
public bool CanExecute(object parameter)
{
Delegate[] targets = m_CanExecuteTargets.GetInvocationList();
foreach (Func<bool> target in targets)
{
m_Enabled = false;
bool localEnable = target.Invoke();
if (localEnable)
{
m_Enabled = true;
break;
}
}
return m_Enabled;
}
public event EventHandler CanExecuteChanged = delegate { };
public void Execute(object parameter)
{
if (m_Enabled)
m_ExecuteTargets(parameter != null ? parameter.ToString() : null);
}
#endregion
public event Action<string> ExecuteTargets
{
add
{
m_ExecuteTargets += value;
}
remove
{
m_ExecuteTargets -= value;
}
}
public event Func<bool> CanExecuteTargets
{
add
{
m_CanExecuteTargets += value;
CanExecuteChanged(this, EventArgs.Empty);
}
remove
{
m_CanExecuteTargets -= value;
CanExecuteChanged(this, EventArgs.Empty);
}
}
}
,並在我的視圖模型(這是在上下文中綁定使事情綁定!!!):
//called in ctor where newEvent is defined : StringDelegateCommand newEvent;
private void setNewEventCommand()
{
newEvent = new StringDelegateCommand();
newEvent.CanExecuteTargets += isThereAnotherNewEvent;
newEvent.ExecuteTargets += exacuteNewEvent;
NewEvent = newEvent;
}
void exacuteNewEvent(string message)
{
Window1 w = new Window1();
w.ShowDialog();
}
當我點擊按鈕什麼都沒發生時,我做錯了什麼?有人能幫我理解我的錯誤...
謝謝...
編輯我應該提到這是什麼compliler寫道:
System.Windows.Data錯誤:40:BindingExpression路徑錯誤:在「對象未找到 'NewEvent' 屬性'''viewModel'(HashCode = 18612316)'。 BindingExpression:路徑= NewEvent; DataItem ='viewModel'(HashCode = 18612316);目標元素是'Button'(Name ='');目標屬性是'命令'(類型'ICommand')
我希望我的spp能夠被xmal驅動,所以當有人更換代碼時,它將是可移植的 – 2010-11-07 11:29:37