🚀 How to Dynamically Copy Matching Fields Between Tables in X++ using DictTable

 In Microsoft Dynamics AX (X++), there are many scenarios where you need to duplicate data from one table to another—especially during custom import, duplication, or versioning processes.

Traditionally, this is done by manually assigning each field:

targetTable.Field1 = sourceTable.Field1;

targetTable.Field2 = sourceTable.Field2;

...

But what if the tables have many fields? Or maybe you’re dealing with multiple similar table pairs?

That’s where the powerful DictTable class comes in. Let’s walk through how to use it to copy matching fields dynamically between two tables.

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💡 Use Case: Copy Customer Templates

Let’s assume you have these tables:

• CustTemplateHeader – stores predefined customer templates.

• CustTemplateHeaderHistory – a historical copy of templates for versioning.

You want to copy records from CustTemplateHeader to CustTemplateHeaderHistory, but only for fields that exist in both tables.

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✅ The Solution Using DictTable

SalesHeaderTemplate   salesHeader;

SalesHeaderHistory    salesHeaderHistory;

SalesTemplateGroup    templateGroup;

SalesTemplateGroup    templateGroup_TDS;

while select salesHeader

    where salesHeader.TemplateGroupId == templateGroup.RecId

{

    salesHeaderHistory.clear();

    DictTable dictFrom = new DictTable(tableNum(SalesHeaderTemplate));

    DictTable dictTo   = new DictTable(tableNum(SalesHeaderHistory));

    int fieldId;

    for (fieldId = dictFrom.fieldNext(0); fieldId; fieldId = dictFrom.fieldNext(fieldId))

    {

        str fieldName = dictFrom.fieldName(fieldId);

        FieldId toFieldId = dictTo.fieldName2Id(fieldName);

        if (toFieldId)

        {

            anyType value = salesHeader.(fieldId);

            salesHeaderHistory.(toFieldId) = value;

        }

    }

    salesHeaderHistory.RecId = 0;

    salesHeaderHistory.TemplateGroupId = templateGroup_TDS.RecId;

    salesHeaderHistory.insert();

}

🧠 Why This Approach Rocks

• ✅ No need to hardcode fields

• ✅ Automatically adapts to schema changes

• ✅ Great for data versioning or duplication logic

• ✅ Scales across multiple similar table pairs

⚠️ Points to Remember

• This technique only works for matching field names and compatible data types.

• You may want to exclude system fields like RecId, CreatedDateTime, etc.

• Set RecId = 0 to prevent conflicts and let the system assign a new one.

🔁 Bonus Tip: Turn It Into a Reusable Function

You could even encapsulate this logic into a utility method or static class so it can be reused across your project.

🔧 Reusable Utility Class: TableCopyHelper

📁 Step 1: Create a new class

Create a new class in AOT or through Visual Studio, name it something like: TableCopyHelper.

public class TableCopyHelper

{

    /// <summary>

    /// Copies matching fields from one table buffer to another.

    /// Skips the RecId field to avoid duplicate key issues.

    /// </summary>

    /// <param name="source">Source table buffer</param>

    /// <param name="target">Target table buffer</param>

    /// <param name="preserveRecId">If false, clears the RecId to force insert as a new    record</param>

    public static void copyMatchingFields(Common source, Common target, boolean preserveRecId = false)

    {

        DictTable dictFrom = new DictTable(source.TableId);

        DictTable dictTo   = new DictTable(target.TableId);

        FieldId   fieldId;

        FieldId   recIdFieldId = fieldNum(Common, RecId);

        for (fieldId = dictFrom.fieldNext(0); fieldId != 0; fieldId = dictFrom.fieldNext(fieldId))

        {

            str fieldName = dictFrom.fieldName(fieldId);

            FieldId toFieldId = dictTo.fieldName2Id(fieldName);

            // Skip if no matching field in target

            if (toFieldId == 0)

                continue;

            // Skip RecId field explicitly

            if (toFieldId == recIdFieldId)

                continue;

            anyType value = source.(fieldId);

            target.(toFieldId) = value;

        }

        if (!preserveRecId)

        {

            target.(recIdFieldId) = 0;

        }

    }

}

 Step 2: Use It in Your Code

Example: Copy from SalesHeaderTemplate to SalesHeaderHistory

SalesHeaderTemplate salesHeader;

SalesHeaderHistory  salesHeaderHistory;

while select salesHeader

    where salesHeader.TemplateGroupId == templateGroup.RecId

{

    salesHeaderHistory.clear();

    TableCopyHelper::copyMatchingFields(salesHeader, salesHeaderHistory);

    salesHeaderHistory.TemplateGroupId = templateGroup_TDS.RecId;

    salesHeaderHistory.insert();

}

🚀 Benefits

• ✅ Reusable for any pair of similar tables.

• 🛡 Prevents accidental copying of RecId, timestamps, or AutoIdentification fields.

• 🧼 Cleaner calling code with less repetitive logic.

• 📈 Easier maintenance — any future logic updates are made in one place.