c# 表达式 lambda 到 vb.net

Question

使用转换器（Redgate、Telerik 等）后，我无法将此表达式 c# 转换为 vb.net

if (afterItemRemoved != null)
        {
            cacheItemPolicy.RemovedCallback = x => afterItemRemoved(
                x.CacheItem.Key,
                (T)x.CacheItem.Value);
        }

我尝试了以下表达式但没有成功 (Reflector 8.5 de RedGate y converter.telerik.com)

If (afterItemRemoved IsNot Nothing) Then
    cacheItemPolicy.RemovedCallback = x => afterItemRemoved.Invoke(x.CacheItem.Key, DirectCast(x.CacheItem.Value, T))
End If


If afterItemRemoved IsNot Nothing Then
    cacheItemPolicy.RemovedCallback = Function(x) afterItemRemoved(x.CacheItem.Key, DirectCast(x.CacheItem.Value, T))
End If

Answer 1

正在查看 RemovedCallback we can see that the required delegate signature is a void method (A Sub in VB.Net) (see CacheEntryRemovedCallback) 的文档。

所以所需的 lambda 表达式必须是 "Sub Lambda" 而不是 "Function lambda"

If afterItemRemoved IsNot Nothing Then
    cacheItemPolicy.RemoveCallback =
        Sub(x) afterItemRemoved(x.CacheItem.Key, DirectCast(x.CacheItem.Value, T))
End If

c# 表达式 lambda 到 vb.net

c# Expression lambda to vb.net

c#

vb.net

lambda

expression