[英]DataGridCheckBoxColumn does not update in MVVM when property is changed
[英]MVVM View binding does not update even with Property Changed fired when update happens from an event handler
我面臨以下問題:我使用一個類來封裝串行端口操作,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)
{
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; }
}
當它檢測到符合我標准的正確序列號時,將觸發onSerialNumberDetected事件。 在視圖模型中,我將此事件疊加為以下內容:
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)); }
}
我的視圖綁定如下
<Window.DataContext>
<local:mvm/>
</Window.DataContext>
<Label FontFamily="Console"
FontSize="20"
Content="{Binding SerialNumber}"
Margin="5"
VerticalAlignment="Center"
Width="400"/>
在調試期間,視圖模型可以從事件中接收序列號,但視圖不會更新。
您正在通知錯誤的屬性名稱:
public string SerialNumber
{
get { return _sn; }
set { _sn = value; NotifyPropertyChanged(nameof(_sn)); }
}
而不是NotifyPropertyChanged(nameof(_sn))
應該是NotifyPropertyChanged(nameof(SerialNumber));
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