组合框未在WPF中显示值

Question

在这里，我将通过wpf中的数据表绑定组合框，但组合框未在fornt端显示值，任何人都可以知道这是怎么回事。这也是代码

//XAML
<ComboBox Canvas.Left="148" Canvas.Top="62" Height="23" 
          Name="cmbGameProfile" Width="217" 
          ItemsSource="{Binding Path=PROFILE_NAME}" 
          DisplayMemberPath="PROFILE_NAME"  />     

//Code-behind
public static void GameProfileList(ComboBox ddlCategoryType)
{
    try
    {
            DataTable dtGameProfileList = null;   
            try
            {
                ClsDataLayer objDataLayer = new ClsDataLayer();
                objDataLayer.AddParameter("@REF_USER_ID",0);
                dtGameProfileList = objDataLayer.ExecuteDataTable("COMNODE_PROC_GetGameProfile");
                if (dtGameProfileList != null && dtGameProfileList.Rows.Count > 0)
                {
                    ddlCategoryType.DataContext = dtGameProfileList;
                    ddlCategoryType.DisplayMemberPath = dtGameProfileList.Rows[0]["PROFILE_NAME"].ToString();
                    ddlCategoryType.SelectedValuePath = dtGameProfileList.Rows[0]["PROFILE_ID"].ToString();
                }
            }
            catch (Exception)
            {
                throw;
            }                                  
    }
    catch
    {
    }
}

Answer 1

据我了解， PROFILE_NAME只是您搜索结果中的一列。 当ItemsSource需要设置为IEnumerable时，它已绑定属性PROFILE_NAME 。 您需要将其设置为DataTable某些视图，这样

ddlCategoryType.ItemsSource = dtGameProfileList.DefaultView;

要么

ddlCategoryType.ItemsSource = new DataView(dtGameProfileList);

Answer 2

考虑到WPF会在呈现之前尝试创建绑定，因此您可能要考虑使用ObservableCollection。

在您的xaml中，您将ItemsSource更新为ItemsSource =“ {Binding YourClassInstanceMember}”，然后在GameProfileList（..）中，将非可观察的集合类转换为ObservableCollection并将其分配给您的后备字段（随后会通知UI进行更新）。

一些推荐的阅读

[数据绑定概述] http://msdn.microsoft.com/zh-cn/library/ms752347(v=vs.110).aspx

[INotifyPropertyChanged]

http://msdn.microsoft.com/zh-CN/library/vstudio/system.componentmodel.inotifypropertychanged

用伪代码..

<Window xmlns:vm="clr-namespace:YourProject.YourViewModelNamespace">
    <Window.DataContext>
        <vm:YourViewViewModel />
    </Window.DataContext>
    <ComboBox ItemsSource="{Binding GameProfileListItems}"/>
</Window>

public class YourViewViewModel : ViewModelBase (this is something that implements INotifyPropertyChanged)
{
    ObservableCollection<string> _gameProfileListItems;
    ObservableCollection<string> GameProfileListItems
    {
        get { return _gameProfileListItems; }
        set { _gameProfileListItems = value; OnPropertyChanged("GameProfileListItems"); }
    }

    public void SetGameProfileListItems()
    {
        //    go and get your data here, transfer it to an observable collection
        //    and then assign it to this.GameProfileListItems (i would recommend writing a .ToObservableCollection() extension method for IEnumerable)
        this.GameProfileListItems = SomeManagerOrUtil.GetYourData().ToObservableCollection();
    }
}

public class YourView : Window
{
    public void YourView()
    {
        InitializeComponent();

        InitializeViewModel();
    }

    YourViewViewModel ViewModel
    {
        { get return this.DataContext as YourViewViewModel; }
    }

    void InitializeViewModel()
    {
        this.ViewModel.SetGameProfileListItems();
    }
}