c#在设计用于处理异常和保留堆栈跟踪的方法中重新抛出异常

Question

我想编写一个处理异常的方法,并在catch块内调用.根据传递的异常的类型,异常要么作为新异常的内部异常传递,要么只是重新抛出.如何在第二种情况下保留堆栈跟踪？

示例:

public void TestMethod()
{
    try
    {
        // can throw an exception specific to the project or a .Net exception 
        SomeWorkMethod() 
    }
    catch(Exception ex)
    {
        HandleException(ex);
    }
}

private void HandleException(Exception ex)
{
    if(ex is SpecificException)
         throw ex; //will not preserve stack trace...
    else
         throw new SpecificException(ex);
}

我不想做的是,因为模式在很多地方重复,并且没有因子分解:

try
{
    SomeWorkMethod();
}
catch(Exception ex)
{
    if(ex is SpecificException)
         throw;
    else
         throw new SpecificException(ex);
}

Answer 1

您需要在throw不指定异常的情况下使用以保留堆栈跟踪.这只能在catch块内完成.您可以做的是返回HandleException而不抛出原始异常,然后立即使用throw:

public void TestMethod()
{
    try
    {
        // can throw an exception specific to the project or a .Net exception 
        SomeWorkMethod() 
    }
    catch(Exception ex)
    {
        HandleException(ex);
        throw;
    }
}

private void HandleException(Exception ex)
{
    if(ex is SpecificException)
         return;
    else
         throw new SpecificException(ex);
}

只要您仅用于is对异常进行分类,首选方法是两个catch块:

public void TestMethod()
{
    try
    {
        // can throw an exception specific to the project or a .Net exception 
        SomeWorkMethod() 
    }
    catch (SpecificException)
    {
        throw;
    }
    catch(Exception ex)
    {
        throw new SpecificException(ex);
    }
}

使用C#6.0,您还可以使用when异常来解决:

public void TestMethod()
{
    try
    {
        // can throw an exception specific to the project or a .Net exception 
        SomeWorkMethod() 
    }
    catch(Exception ex) when (!(ex is SpecificException))
    {
        throw new SpecificException(ex);
    }
}