：并非所有代码路径都返回值

Question

我有一个dialogContent TemplateSelector，用于打开一个对话框。我收到这个错误;

  

错误2＆＃39; CentralPrintUnitSystem.Dialogs.DialogContentTemplateSelector.SelectTemplate（object，System.Windows.DependencyObject）＆＃39 ;:并非所有代码路径都返回值C：\ Users \ 2337704 \ documents \ visual studio 2012 \ Projects \ CentralPrintUnitSystem \ CentralPrintUnitSystem \ Dialogs \ DialogContentTemplateSelector.cs 22 53 CentralPrintUnitSystem

我的DialogContentTemplateSelector代码是;

namespace CentralPrintUnitSystem.Dialogs
{
    public class DialogContentTemplateSelector : DataTemplateSelector
    {
        public override System.Windows.DataTemplate SelectTemplate(object item, System.Windows.DependencyObject container)
        {
            FrameworkElement element = container as FrameworkElement;

            if (item != null && container != null)
            {
                if (item is CentralPrintUnitSystem.Dialogs.EditNewEntryDialogView)
                {
                    return element.FindResource("EditNewEntryDataTemplate") as DataTemplate;
                }

                if (item is   CentralPrintUnitSystem.Dialogs.EditNewDepartmentDialogView)
                {
                    return element.FindResource("CreateNewDepartmentDataTemplate") as DataTemplate;
                }
                else
                {
                    return null;
                }

                return null;
            }
        }
    }
}

所有和任何帮助将不胜感激。

Answer 1

这应该可以解决这个错误 -

public override System.Windows.DataTemplate SelectTemplate(object item, System.Windows.DependencyObject container)
        {
                FrameworkElement element = container as FrameworkElement;
                if (item != null && container != null)
            {

                if (item is CentralPrintUnitSystem.Dialogs.EditNewEntryDialogView)
            {

                return element.FindResource("EditNewEntryDataTemplate") as DataTemplate;
            }

                if (item is   CentralPrintUnitSystem.Dialogs.EditNewDepartmentDialogView)
            {

                return element.FindResource("CreateNewDepartmentDataTemplate") as DataTemplate;
            }

            else
            {
                return null;
            }

            return null;
            }
        return null;
        }