當組合框打開時從ObjectDataProvider獲取數據

Question

如何獲取每次擴展組合框而不是一次的ObjectDataProvider觸發器？

<UserControl.Resources> 
    <ObjectDataProvider x:Key="possibleExpressionValues" 
       MethodName="GetWatchVariableNames" 
       ObjectType="{x:Type mu:UserInterfaceHelper}" IsInitialLoadEnabled="False"> 
    </ObjectDataProvider> 
</UserControl.Resources> 

<Grid> 
    <ComboBox IsEditable="True" Text="{Binding ID}" ItemsSource="{Binding Source={StaticResource possibleExpressionValues}}" VerticalAlignment="Top" /> 
</Grid> 

Answer 1

隨着ObjectDataProvider的被觸發，你的意思是你想有一個新的UserInterfaceHelper對象創建？

在這種情況下，將組合框的DropDownOpened事件掛接到以下方法。

private void ComboBox_DropDownOpened(object sender, EventArgs e) 
{ 
    ObjectDataProvider odp = Resources["possibleExpressionValues"] as ObjectDataProvider; 
    odp.ObjectType = null; 
    odp.ObjectInstance = new UserInterfaceHelper(); 
}