c# - С#。错误“具有不同签名的预期方法”。但显示相同的签名
问题描述
我有事件处理程序c_CriticalSituationHappened
方法Program.cs
void c_CriticalSituationHappened(object sender, CriticalSituationGacEventArgs e)
{
if (e.TypeDisrepair != TypeDisrepairGac.None)
{
start_time = DateTime.UtcNow;
typeDisrepair = e.TypeDisrepair;
WriteLine("Crit sit time: " + start_time);
isStarted = true;
}
}
如果我将它移到类库中,我会导入它。
public class CorrectBehaviorCheck
{
public void CriticalSituationHappened1(object sender, CriticalSituationGacEventArgs e)
{
if (e.TypeDisrepair != TypeDisrepairGac.None)
{
criticalSituationStartTime = DateTime.Now;
TypeDisrepair = e.TypeDisrepair;
Console.WriteLine("111");
isStarted = true;
}
}
}
签名保持完全相同。 但如果尝试
using cbc = mymodule.CorrectBehaviorCheck;
class Program{
static void Main(string[] args){
cbc a = new cbc();
CriticalSituationHappened += a.CriticalSituationHappened1;
}
}
代替
class Program{
static void Main(string[] args){
CriticalSituationHappened += c_CriticalSituationHappened;
}
}
我有一个错误Expected a method with 'void CriticalSituationHappened1(object?, CriticalSituationGacEventArgs)' signature
我做错了什么?两种方法具有相同的签名。为什么当我将方法放入类库时程序会中断?
在 Program.cs 中:
protected virtual void OnCriticalSituationHappened(CriticalSituationGacEventArgs e)
{
EventHandler<CriticalSituationGacEventArgs> handler = CriticalSituationHappened;
if (handler != null)
{
handler(this, e);
}
}
public static event EventHandler<CriticalSituationGacEventArgs> CriticalSituationHappened;
解决方案
您的错误是由于CriticalSituationGacEventArgs
跨程序集的多个定义而发生的。为了说明一点,在主程序集(我们称之为A
)中,我们有:
namespace A
{
using cbc = B.CorrectBehaviorCheck;
public class CriticalSituationGacEventArgs : EventArgs
{
public string Message { get; set; }
}
public class Program
{
public static event EventHandler<A.CriticalSituationGacEventArgs> CriticalSituationHappened;
public static void Main(string[] args)
{
cbc a = new cbc();
CriticalSituationHappened += a.CriticalSituationHappened1;
CriticalSituationHappened(null, new A.CriticalSituationGacEventArgs { Message = "Hello!" });
}
}
}
然后在外部程序集中(我们称之为B
)我们有:
namespace B
{
public class CriticalSituationGacEventArgs : EventArgs
{
public string Message { get; set; }
}
public class CorrectBehaviorCheck
{
public void CriticalSituationHappened1(object sender, B.CriticalSituationGacEventArgs e)
{
Console.WriteLine("Listening in CorrectBehaviorCheck.CriticalSituationHappened1: " + e.Message);
}
}
}
这会导致 处的错误CriticalSituationHappened += a.CriticalSituationHappened1
。为了进一步理解这一点,我们可以更明确地将其定义为:
CriticalSituationHappened += (object sender, A.CriticalSituationGacEventArgs e) => a.CriticalSituationHappened1(sender, e);
这是试图传递A.CriticalSituationGacEventArgs
给期望的参数B.CriticalSituationGacEventArgs
,它会给出以下错误:
CS1503 Argument 2: cannot convert from 'A.CriticalSituationGacEventArgs' to 'B.CriticalSituationGacEventArgs'
因为编译器无法知道如何从一种类型转换为另一种类型。鉴于您的情况,有几种选择可以解决此问题:
1.手动转换事件args
CriticalSituationHappened += (sender, e) =>
a.CriticalSituationHappened1(sender, new B.CriticalSituationGacEventArgs
{
Message = e.Message,
// set other properties
});
2.在共享程序集中定义一次事件参数
创建一个新项目(例如MyEventArgs
)并在该项目中定义CriticalSituationGacEventArgs
一次。然后A
和B
都可以MyEventArgs.CriticalSituationGacEventArgs
在定义事件(in A
)和处理事件(in B
)时引用。这也避免了在A
or中定义单一类型的循环依赖B
。
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