52 lines
1.0 KiB
Plaintext
52 lines
1.0 KiB
Plaintext
When raising an event, two arguments are expected by the ``++EventHandler++`` delegate: Sender and event-data. There are three guidelines regarding these parameters:
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* Do not pass ``++null++`` as the sender when raising a non-static event.
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* Do pass ``++null++`` as the sender when raising a static event.
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* Do not pass ``++null++`` as the event-data. If no data should be passed, then ``++EventArgs.Empty++`` should be used.
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This rule raises an issue when any of these guidelines is not met.
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== Noncompliant Code Example
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[source,text]
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----
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using System;
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namespace MyLibrary
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{
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class Foo
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{
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public event EventHandler ThresholdReached;
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protected virtual void OnThresholdReached(EventArgs e)
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{
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ThresholdReached?.Invoke(null, e); // Noncompliant
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}
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}
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}
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----
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== Compliant Solution
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[source,text]
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----
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using System;
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namespace MyLibrary
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{
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class Foo
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{
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public event EventHandler ThresholdReached;
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protected virtual void OnThresholdReached(EventArgs e)
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{
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ThresholdReached?.Invoke(this, e);
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}
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}
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}
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----
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