的DataGrid不绑定到的ObservableCollection

我有我的观点一个按钮，在视图模型执行此方法：的DataGrid不绑定到的ObservableCollection

public void GetAudits(Guid? userId, DateTime? from, DateTime? to, string form) 
     { 
      StringBuilder sCondition = new StringBuilder("WHERE 0=0"); 

      if (userId != null && userId != Guid.Empty) 
       sCondition.Append(string.Format(" AND UserId = '{0}' ", userId)); 

      if (!string.IsNullOrEmpty(form)) 
       sCondition.Append(string.Format(" AND FormName = '{0}' ", form)); 


      string query = string.Format("SELECT * FROM Common.TbHistoryLog {0}", sCondition); 
      Audits = new ObservableCollection<HistoryLog>(oContext.Database.SqlQuery<HistoryLog>(query).ToList()); 

     }

的Audits属性：

public ObservableCollection<HistoryLog> Audits 
    { 
     get 
     { 
      return audits; 
     } 
     set 
     { 
      audits = value; 
     } 
    } 
    ObservableCollection<HistoryLog> audits;

，这是为处理程序按钮：

private void BtnSearch(object sender, RoutedEventArgs e) 
     { 
      var userId = ((TbUsers)cmbUsers.SelectedItem)?.UserId; 
      var from = dtFromDate.Value; 
      var to = dtToDate.Value; 
      var form = ((BlCommon.TbObjects)cmbForms.SelectedItem)?.ObjectRealName; 
      using (ClsUserTransactions oUserTrans = new ClsUserTransactions()) 
      { 
       oUserTrans.GetAudits(userId, from, to, form); 
      } 
     }

但是当我点击按钮，dataGrid没有得到更新与th Ë审计收集：

<DataGrid Name="gvHistory" Grid.Column="0" Grid.Row="9" Margin="2" Visibility="Visible" ItemsSource="{Binding Audits}" Grid.ColumnSpan="8" IsReadOnly="True" Grid.RowSpan="2" AutoGenerateColumns="True" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" CanUserAddRows="False"/>

当我调试，我注意到，吸气块不打

来源

2017-08-16 Mohamed Elshawaf

在ViewModel中实现INotifyPropertyChanged，并在setter中为“审计”属性提出PropertyChanged事件 – ASh

可观察集合属性应为只读。他们向用户界面提供更改通知。添加和删除集合中的元素，请勿替换集合。 – Will

您的视图模型应该实现INotifyPropertyChanged接口，然后通知对审计二传手属性变化：

public class ViewModel : INotifyPropertyChanged 
{ 
    public event PropertyChangedEventHandler PropertyChanged; 
    protected void OnPropertyChanged(string name) 
    { 
     PropertyChangedEventHandler handler = PropertyChanged; 
     if (handler != null) 
     { 
      handler(this, new PropertyChangedEventArgs(name)); 
     } 
    } 
...

public ObservableCollection<HistoryLog> Audits 
{ 
    get 
    { 
     return audits; 
    } 
    set 
    { 
     audits = value; 
     OnPropertyChanged("Audits"); 
    } 
} 
ObservableCollection<HistoryLog> audits;

来源

2017-08-16 08:09:57 Lamelas84

它不起作用 –

你为什么不SIMPL Ÿ明确和重新填充相同ObservableCollection：

public void GetAudits(Guid? userId, DateTime? from, DateTime? to, string form) 
{ 
    StringBuilder sCondition = new StringBuilder("WHERE 0=0"); 

    if (userId != null && userId != Guid.Empty) 
     sCondition.Append(string.Format(" AND UserId = '{0}' ", userId)); 

    if (!string.IsNullOrEmpty(form)) 
     sCondition.Append(string.Format(" AND FormName = '{0}' ", form)); 


    string query = string.Format("SELECT * FROM Common.TbHistoryLog {0}", sCondition); 
    if (Audits != null) 
    { 
     Audits.Clear(); 
     var newItems = oContext.Database.SqlQuery<HistoryLog>(query).ToList(); 
     if (newItems != null) 
      foreach (var newItem in newItems) 
       Audits.Add(newItem); 
    } 
}

其次，这将创建一个新实例ClsUserTransactions的：

ClsUserTransactions oUserTrans = new ClsUserTransactions())

您需要将项目添加到一个该DataGrid是绑定以及你肯定不应该立即处理实例后，你已经填充其审计集合...：

private void BtnSearch(object sender, RoutedEventArgs e) 
{ 
    var userId = ((TbUsers)cmbUsers.SelectedItem)?.UserId; 
    var from = dtFromDate.Value; 
    var to = dtToDate.Value; 
    var form = ((BlCommon.TbObjects)cmbForms.SelectedItem)?.ObjectRealName; 
    ClsUserTransactions oUserTrans = gvHistory.DataContext as ClsUserTransactions; 
    oUserTrans.GetAudits(userId, from, to, form); 
}

来源

2017-08-16 10:05:06 mm8

的DataGrid不绑定到的ObservableCollection

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