[英]The type or namespace name 'T' could not be found (are you missing a using directive or an assembly reference?)
[英]Getting error The type or namespace name 'T' could not be found (are you missing a using directive or an assembly reference?)
我收到编译错误错误“无法找到类型或命名空间名称'T'(您是否缺少using指令或程序集引用?
以下是我的代码:
static class ExtensionMethods
{
public static Collection<T> ToCollection(this IEnumerable<T> source)
{
Collection<T> sourceCollection = new Collection<T>();
foreach (T currentSourceInstance in source)
{
sourceCollection.Add(currentSourceInstance);
}
return sourceCollection;
}
}
把它改成这个:
public static class ExtensionMethods
{
public static Collection<T> ToCollection<T>(this IEnumerable<T> source)
{
Collection<T> sourceCollection = new Collection<T>();
foreach (T currentSourceInstance in source)
{
sourceCollection.Add(currentSourceInstance);
}
return sourceCollection;
}
}
注意ToCollection<T>
,否则编译器不知道这个T
来自何处。
你可以像这样调用它(在这个例子中Thing
是你的自定义类型):
var items = new List<Thing>();
var collection = items.ToCollection<Thing>();
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