将以下行从C#转换为VB.Net时,我得到了
表达式不产生值
C#
query.ToList().ForEach(ti => cat.Add(ti));
VB.NET
query.ToList().ForEach(Function(ti) cat.Add(ti))
C#代码:
void MainWindow_Loaded(object sender, RoutedEventArgs e)
{
new DesignerMetadata().Register();
var toolbox = new ToolboxControl();
var cat = new ToolboxCategory("Standard Activities");
var assemblies = new List<Assembly>();
assemblies.Add(typeof(Send).Assembly);
assemblies.Add(typeof(Delay).Assembly);
assemblies.Add(typeof(ReceiveAndSendReplyFactory).Assembly);
var query = from asm in assemblies
from type in asm.GetTypes()
where type.IsPublic &&
!type.IsNested &&
!type.IsAbstract &&
!type.ContainsGenericParameters &&
(typeof(Activity).IsAssignableFrom(type) ||
typeof(IActivityTemplateFactory).IsAssignableFrom(type))
orderby type.Name
select new ToolboxItemWrapper(type);
query.ToList().ForEach(ti => cat.Add(ti));
toolbox.Categories.Add(cat);
Grid.SetColumn(toolbox, 0);
Grid.SetRow(toolbox, 1);
LayoutGrid.Children.Add(toolbox);
}
我想要Vb.net转换。当我在vb.net中转换此代码时,在query.ToList()。ForEach(Function(ti)cat.Add(ti))中出现错误,此行.error是Expression不会产生值。
转换后的VB.NET代码
Private Sub MainWindow_Loaded(ByVal sender As Object, ByVal e As RoutedEventArgs)
Dim metadata = New DesignerMetadata()
metadata.Register()
'Create the ToolBoxControl
Dim toolbox = New ToolboxControl()
'Create a collection of category items
Dim cat = New ToolboxCategory("Standard Activities")
Dim assemblies = New List(Of Assembly)()
assemblies.Add(GetType(SendAndReceiveReplyFactory).Assembly)
assemblies.Add(GetType(Delay).Assembly)
assemblies.Add(GetType(ReceiveAndSendReplyFactory).Assembly)
Dim query = _
From asm In assemblies
From type In asm.GetTypes() _
Where type.IsPublic AndAlso Not type.IsNested AndAlso Not type.IsAbstract AndAlso Not type.ContainsGenericParameters AndAlso (GetType(Activity).IsAssignableFrom(type) OrElse GetType(IActivityTemplateFactory).IsAssignableFrom(type)) _
Order By type.Name
Select New ToolboxItemWrapper(type)
query.ToList().ForEach(Function(ti) cat.Add(ti))
toolbox.Categories.Add(cat)
Grid.SetColumn(toolbox, 0)
Grid.SetRow(toolbox, 1)
LayoutGrid.Children.Add(toolbox)
End Sub
将有问题的行更改为该行:
query.ToList().ForEach(Sub(ti) cat.Add(ti))
这是必要的,因为没有单独的语法Action<T>
(Sub(T)
)和Func<T>
(Function(t)
)在VB.NET(但不是在C#)。
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