選定的價值組合框沒有約束力

Question

好吧，所以我花了幾個小時，試圖找出這一點，我不能。 我有下面的組合框，它正確地綁定到我的數據收集。

<ComboBox Name="cbx" Width="250" Height="25" 
    Visibility="{Binding Path=IsComboBox,Converter={StaticResource BoolConverter}}" 
    ItemsSource="{Binding Path=Answers}" 
    SelectedValuePath="AnswerId" 
    SelectedItem="{Binding Path=SelectedAnswer, Mode=TwoWay}" 
    DisplayMemberPath="Answer"/> 

然而，選定的項目並未填充到我選擇的答案屬性的頂部。我在窗體上放置了一個文本框並將其綁定到了SelectedAnswer.Answer，並且正確地綁定了答案。 出於某種原因，儘管我的組合框不會選擇的答案

• 我看過一些有關組合框屬性的佈局，並試圖改變結合，還可以通過屬性的getter和setter加強，以確保它沒有清理（這不像它會綁定到文本框）

請幫助這一點。

SurveyAnswer：

public class SurveyAnswer : INotifyPropertyChanged 
{ 
    private Guid answerId; 
    public Guid AnswerId 
    { 
     get { return answerId; } 
     set { 
      answerId = value; 
      NotifyPropertyChanged("AnswerId"); 
     } 
    } 

    private string answer; 
    public string Answer 
    { 
     get { return answer; } 
     set { 
      answer = value; 
      NotifyPropertyChanged("Answer"); 
     } 
    } 

    public Guid SurveyLineID { get; set; } 

    private bool isSelected; 
    public bool IsSelected 
    { 
     get { return isSelected; } 
     set { 
      isSelected = value; 
      NotifyPropertyChanged("IsSelected"); 
     } 
    } 


    #region NotifyPropertyChanged 

    public event PropertyChangedEventHandler PropertyChanged; 
    private void NotifyPropertyChanged(String info) 
    { 
     if (PropertyChanged != null) 
     { 
      PropertyChanged(this, new PropertyChangedEventArgs(info)); 
     } 
    } 

    #endregion   

} 

Answer 1

我想你需要的SelectedItem改變的SelectedValue。有時參數順序也很重要。

<ComboBox Name="cbx" Width="250" Height="25"               
    Visibility="{Binding Path=IsComboBox,Converter={StaticResource BoolConverter}}" 
    ItemsSource="{Binding Path=Answers}"   
    SelectedValue="{Binding Path=SelectedAnswer, Mode=TwoWay}" 
    DisplayMemberPath="Answer" SelectedValuePath="AnswerId"/> 

這是有幫助的： http://johnpapa.net/binding-to-silverlight-combobox-and-using-selectedvalue-selectedvaluepath-and-displaymemberpath