I want to test the following code:
private bool TestException(Exception ex)
{
if ((Marshal.GetHRForException(ex) & 0xFFFF) == 0x4005)
{
return true;
}
return false;
}
I'd like to set up the Exception object somehow to return the correct HResult, but I can't see a field in the Exception class which allows this.
How would I do this?
I found three ways to do this:
Use the System.Runtime.InteropServices.ExternalException class, passing in the error code as a parameter:
var ex = new ExternalException("-", 0x4005);
Thanks to @HansPassant for his comment explaining this.
Pass a mock exception using inheritance to access a protected field:
private class MockException : Exception
{
public MockException() { HResult = 0x4005; }
}
var ex = new MockException();
Use .NET Reflection to set the underlying field:
BindingFlags flags = BindingFlags.Instance | BindingFlags.NonPublic;
FieldInfo hresultFieldInfo = typeof(Exception).GetField("_HResult", flags);
var ex = new Exception();
hresultFieldInfo.SetValue(ex, 0x4005);
Passing any one of these exceptions to the method in the question, will result in that method returning true. I suspect the first method is most useful.