rspec/rules/S4583/csharp/rule.adoc

include::../why-dotnet.adoc[]

== How to fix it

=== Code examples

==== Noncompliant code example

`BeginInvoke` without callback:

[source,csharp,diff-id=1,diff-type=noncompliant]
----
public delegate string AsyncMethodCaller();

public static void Main() 
{
    AsyncExample asyncExample = new AsyncExample();
    AsyncMethodCaller caller = new AsyncMethodCaller(asyncExample.MyMethod);

    // Initiate the asynchronous call.
    IAsyncResult result = caller.BeginInvoke(null, null); // Noncompliant: not paired with EndInvoke
}
----

`BeginInvoke` with callback:

[source,csharp,diff-id=2,diff-type=noncompliant]
----
public delegate string AsyncMethodCaller();

public static void Main() 
{
    AsyncExample asyncExample = new AsyncExample();
    AsyncMethodCaller caller = new AsyncMethodCaller(asyncExample.MyMethod);

    IAsyncResult result = caller.BeginInvoke(
        new AsyncCallback((IAsyncResult ar) => {}),
        null); // Noncompliant: not paired with EndInvoke
}
----

==== Compliant solution

`BeginInvoke` without callback:

[source,csharp,diff-id=1,diff-type=compliant]
----
public delegate string AsyncMethodCaller();

public static void Main() 
{
    AsyncExample asyncExample = new AsyncExample();
    AsyncMethodCaller caller = new AsyncMethodCaller(asyncExample.MyMethod);

    IAsyncResult result = caller.BeginInvoke(null, null);

    string returnValue = caller.EndInvoke(result);
}
----

`BeginInvoke` with callback:

[source,csharp,diff-id=2,diff-type=compliant]
----
public delegate string AsyncMethodCaller();

public static void Main() 
{
    AsyncExample asyncExample = new AsyncExample();
    AsyncMethodCaller caller = new AsyncMethodCaller(asyncExample.MyMethod);

    IAsyncResult result = caller.BeginInvoke(
        new AsyncCallback((IAsyncResult ar) =>
            {
                // Call EndInvoke to retrieve the results.
                string returnValue = caller.EndInvoke(ar);
            }), null);
}
----

include::../resources-dotnet.adoc[]

include::../rspecator.adoc[]