使用MVVM範例填充與c＃的組合框使用MVVM範例填充組合框

Question

我想在組合框中顯示'用戶組'，並將選定的用戶組鍵綁定到我的視圖模型中的變量。我正在使用MVVM範例，我知道它非常接近工作，但我無法看到問題出在哪裏。用戶組在登錄後通過網絡通話動態填充。我知道綁定正在工作，因爲如果我刪除了xaml中的DisplayMemberPath屬性，我看到了這些組。

班裏用戶組

public class UserGroup 
{ 

    public long ugp_id; 
    public String groupName; 
    public float ugp_credits; 
    public String logo; 

    public UserGroup() 
    { 
    } 
} 

我有一個XAML

.... 
<ComboBox Grid.Row="0" Grid.Column="2" Height="30" VerticalAlignment="Top" Margin="0,4,0,0" 
     ItemsSource="{Binding userGroupCollection, Mode=OneWay}" 
     DisplayMemberPath="groupName" 
     SelectedValue="{Binding SelectedUgpId}" 
     SelectedValuePath="ugp_id" > 

在我的ViewModel類我建立了一個觀察的集合：

public ObservableCollection<UserGroup> _userGroupCollection; 
    public ObservableCollection<UserGroup> userGroupCollection 
    { 
     get 
     { 
      return _userGroupCollection; 
     } 
     set 
     { 
      if (_userGroupCollection != value) 
      { 
       this._userGroupCollection = value; 
       DynamicOnPropertyChanged(); 
      } 
     } 
    } 

網絡把這個數據照顧正如我預計的那樣...

但是當我在看網頁時看到我看到的組合框條目是空白的輸出窗口（但正確的數字顯示），但此錯誤：

'i3SoftClient.vshost.exe' (CLR v4.0.30319: i3SoftClient.vshost.exe): Loaded 'C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\PresentationFramework-SystemCore\v4.0_4.0.0.0__b77a5c561934e089\PresentationFramework-SystemCore.dll'. Skipped loading symbols. Module is optimized and the debugger option 'Just My Code' is enabled. 
System.Windows.Data Error: 40 : BindingExpression path error: 'ugp_id' property not found on 'object' ''UserGroup' (HashCode=29245900)'. BindingExpression:Path=ugp_id; DataItem='UserGroup' (HashCode=29245900); target element is 'ComboBox' (Name=''); target property is 'NoTarget' (type 'Object') 
System.Windows.Data Error: 40 : BindingExpression path error: 'groupName' property not found on 'object' ''UserGroup' (HashCode=29245900)'. BindingExpression:Path=groupName; DataItem='UserGroup' (HashCode=29245900); target element is 'ComboBox' (Name=''); target property is 'NoTarget' (type 'Object') 
System.Windows.Data Error: 40 : BindingExpression path error: 'ugp_id' property not found on 'object' ''UserGroup' (HashCode=29245900)'. BindingExpression:Path=ugp_id; DataItem='UserGroup' (HashCode=29245900); target element is 'ComboBox' (Name=''); target property is 'NoTarget' (type 'Object') 
System.Windows.Data Error: 40 : BindingExpression path error: 'ugp_id' property not found on 'object' ''UserGroup' (HashCode=29245900)'. BindingExpression:Path=ugp_id; DataItem='UserGroup' (HashCode=29245900); target element is 'ComboBox' (Name=''); target property is 'NoTarget' (type 'Object') 
System.Windows.Data Error: 40 : BindingExpression path error: 'ugp_id' property not found on 'object' ''UserGroup' (HashCode=6695955)'. BindingExpression:Path=ugp_id; DataItem='UserGroup' (HashCode=6695955); target element is 'ComboBox' (Name=''); target property is 'NoTarget' (type 'Object') 

我已經看了看周圍，但我可以似乎無法理解錯誤信息。

Answer 1

你要做這樣的：

public long ugp_id { get; set; } 
public String groupName { get; set; } 

現在再試試:)

什麼錯誤是，那些wernt性能，這些都是單純的變量:) 結合的任何工作成員，您應該如下聲明 :)

Answer 2

您不能使用公共字段進行綁定。你必須使用屬性

public class UserGroup 
{ 

    public long ugp_id { get; set; }; 
    public String groupName { get; set; }; 
    public float ugp_credits { get; set; }; 
    public String logo { get; set; }; 

    public UserGroup() 
    { 
    } 
}