How to: Use the byref Keyword for CLR Interop

Applies To: Microsoft Dynamics AX 2012 R3, Microsoft Dynamics AX 2012 R2, Microsoft Dynamics AX 2012 Feature Pack, Microsoft Dynamics AX 2012

In X++, you use the byref keyword when you call a .NET Framework method that takes parameters by reference.

For more information about how the byref keyword works with value types and reference types, see Understanding the X++ Keyword byref for CLR Interop.

Code Samples

The following C# and X++ code samples work together to show when and how to use the byref keyword.

C# Called Method

The following C# code sample shows a method that takes parameters by reference. Note the C# keywords ref and out, which both mean pass by reference.

using System;
namespace DotNetNamespace {
public class DotNetClass {

static public void CalledCSharp // Method.
        (
        int iLengthOfOldPrefix         // by value
        ,string sWhole                 // by value
        ,ref string sNewPrefixPlusName // by reference
        ,out string sDiscardedPrefix   // by reference
        )
{
    sNewPrefixPlusName = sNewPrefixPlusName
        + sWhole.Substring(iLengthOfOldPrefix);
    sDiscardedPrefix = sWhole.Substring
        (0, iLengthOfOldPrefix);
}}}

X++ Caller Job

The following X++ code sample shows how to use the byref keyword to call the example C# method CalledCSharp.

static void JobByrefCallerXpp(Args _args)
    {
        int iLengthOfOldPrefix;
        str sWhole;
        str sNewPrefix;
    
        str sNewPrefixPlusName
            ,sDiscardedPrefix;
        ;
    
        iLengthOfOldPrefix = 5; // 'Foods' is 5 characters.
        sWhole = "Foods: triangle, square, circle.";
        sNewPrefix = "Shapes";
    
        sNewPrefixPlusName = sNewPrefix;
    
        DotNetNamespace.DotNetClass::CalledCSharp
            (
            iLengthOfOldPrefix
            ,sWhole
            ,byref sNewPrefixPlusName
            ,byref sDiscardedPrefix
            );
    
        info("sNewPrefixPlusName = " + sNewPrefixPlusName);
        info("sDiscardedPrefix = " + sDiscardedPrefix);
    
    /*****  Infolog actual output.
    Message (07:24:21 pm)
    sNewPrefixPlusName = Shapes: triangle, square, circle.
    sDiscardedPrefix = Foods
    *****/
    }

See also

.NET Interop from X++

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