The custom fields in FlexReport are available in C1.Win.FlexReport.CustomFields.4 assembly. You can create your own custom fields and add them to the Report Designer palette. To do that, you have to:

1. Create a custom field class that derives from C1.Win.FlexReport.CustomFields.
2. Register your custom field assembly in C1FlexReportDesigner.4.exe.settings.

For registering a custom field, say MyField, add your control to the <customfields> section in the C1FlexReportDesigner.4.exe.settings file as follows:

<customfields>
<!-- THIS LINE ADDS A NEW FIELD TO THE DESIGNER -->
<item value="MyCustomFieldAssembly;MyCustomFieldAssembly.MyField" />
</customfields>

Note that the code above assumes that your field is called "MyField" and it can be found in the assembly called "MyCustomFieldAssembly". Also, MyCustomFieldAssembly should be in the same folder as the designer.

Following are built-in standard custom fields that are loaded in the FlexReportDesigner application by default:

• SuperLabel
• Maps

The source code for implementing these custom fields is:
<customfields>
<item value="C1.Win.FlexReport.CustomFields;C1.Win.FlexReport.CustomFields.SuperLabel" />
<item value="C1.Win.FlexReport.CustomFields;C1.Win.FlexReport.CustomFields.Map" />
</customfields>