C# MVVM视图绑定不会更新,即使在从事件处理程序进行更新时触发了属性更改
我面临以下问题: 我使用一个类来封装串行端口操作,如下所示:C# MVVM视图绑定不会更新,即使在从事件处理程序进行更新时触发了属性更改,c#,mvvm,C#,Mvvm,我面临以下问题: 我使用一个类来封装串行端口操作,如下所示: public class SNScanner : IDisposable { public string COMPort { get; set; } public int Baudrate { get; set; } SerialPort sp; string Rsv; public SNScanner(string cOMPort, int bauderate) {
public class SNScanner : IDisposable
{
public string COMPort { get; set; }
public int Baudrate { get; set; }
SerialPort sp;
string Rsv;
public SNScanner(string cOMPort, int bauderate)
{
COMPort = cOMPort;
Baudrate = bauderate;
sp = new SerialPort()
{
PortName = COMPort,
BaudRate = Baudrate,
DataBits = 8,
StopBits = StopBits.One,
Parity = Parity.None
};
sp.DataReceived += Sp_DataReceived;
if (!sp.IsOpen)
{
sp.Open();
}
}
private void Sp_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
Thread.Sleep(100);
Rsv = string.Empty;
Rsv = sp.ReadExisting();
if (!string.IsNullOrEmpty(Rsv) && Rsv.Length == 17 )
{
OnSerialNumberDetected(new SerialNumberDetectedEventArgs {
SerialNumber = Rsv.Substring(1,15) });
}
}
#region Serial number detected event
public event EventHandler SerialNumberDetected;
protected virtual void OnSerialNumberDetected(EventArgs e) => SerialNumberDetected?.Invoke(this, e);
public void Dispose()
{
sp.Close();
try
{
sp.Dispose();
}
catch (Exception)
{
}
}
#endregion
}
public class SerialNumberDetectedEventArgs : EventArgs
{
public string SerialNumber { get; set; }
}
myscanner = new SNScanner("COM3", 9600);
SerialNumber = "Empty";
myscanner .SerialNumberDetected += myscanner_SerialNumberDetected;
}
private void myscanner_SerialNumberDetected(object sender, EventArgs e)
{
SerialNumber = ((SerialNumberDetectedEventArgs)e).SerialNumber;
}
private string _sn;
public string SerialNumber
{
get { return _sn; }
set { _sn = value; NotifyPropertyChanged(nameof(_sn)); }
}
当它检测到符合我的条件的正确序列号时,将触发SerialNumber Detected事件。
在视图模型中,我将此事件上标如下:
public class SNScanner : IDisposable
{
public string COMPort { get; set; }
public int Baudrate { get; set; }
SerialPort sp;
string Rsv;
public SNScanner(string cOMPort, int bauderate)
{
COMPort = cOMPort;
Baudrate = bauderate;
sp = new SerialPort()
{
PortName = COMPort,
BaudRate = Baudrate,
DataBits = 8,
StopBits = StopBits.One,
Parity = Parity.None
};
sp.DataReceived += Sp_DataReceived;
if (!sp.IsOpen)
{
sp.Open();
}
}
private void Sp_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
Thread.Sleep(100);
Rsv = string.Empty;
Rsv = sp.ReadExisting();
if (!string.IsNullOrEmpty(Rsv) && Rsv.Length == 17 )
{
OnSerialNumberDetected(new SerialNumberDetectedEventArgs {
SerialNumber = Rsv.Substring(1,15) });
}
}
#region Serial number detected event
public event EventHandler SerialNumberDetected;
protected virtual void OnSerialNumberDetected(EventArgs e) => SerialNumberDetected?.Invoke(this, e);
public void Dispose()
{
sp.Close();
try
{
sp.Dispose();
}
catch (Exception)
{
}
}
#endregion
}
public class SerialNumberDetectedEventArgs : EventArgs
{
public string SerialNumber { get; set; }
}
myscanner = new SNScanner("COM3", 9600);
SerialNumber = "Empty";
myscanner .SerialNumberDetected += myscanner_SerialNumberDetected;
}
private void myscanner_SerialNumberDetected(object sender, EventArgs e)
{
SerialNumber = ((SerialNumberDetectedEventArgs)e).SerialNumber;
}
private string _sn;
public string SerialNumber
{
get { return _sn; }
set { _sn = value; NotifyPropertyChanged(nameof(_sn)); }
}
我的观点如下
<Window.DataContext>
<local:mvm/>
</Window.DataContext>
<Label FontFamily="Console"
FontSize="20"
Content="{Binding SerialNumber}"
Margin="5"
VerticalAlignment="Center"
Width="400"/>
调试期间,视图模型可以从事件接收序列号,但视图不会更新。您正在通知错误的属性名称:
public string SerialNumber
{
get { return _sn; }
set { _sn = value; NotifyPropertyChanged(nameof(_sn)); }
}
不是NotifyPropertyChangednameof,而是应为NotifyPropertyChangednameof序列号 ViewModel的基类是什么?它是否实现INotifyPropertyChanged?事件是在UI线程还是后台线程上触发的?是,我的基本模型实现了INotifyPropertyChanged。默认情况下,串行端口在单独的线程中工作,但在我的视图模型中,我不直接侦听SP事件。谢谢。但是为什么,我曾经更新私有属性content={Binding SerialNumber}将您的视图绑定到SerialNumber属性。因此,您应该通知视图SerialNumber属性已更改。