Rethrow the current exception

To rethrow the current exception, use the throwstatement without passing it an exception.
The following code snippet demonstrates this technique:

try
{
    // Do something dangerous.
}
catch (Exception)
{
    // Log the error.
    // Re-throw the exception.
    throw;
}

Contrast this code with the following version:

try
{
    // Do something dangerous.
}
catch (Exception ex)
{
    // Log the error.
    // Re-throw the exception.
    throw ex;
}

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