How To Fix WD288 - Expression '&' has an invalid type or reference

SAP Error Message - Details

• Message type: E = Error

• Message class: WD - Workflow definition

• Message number: 288

• Message text: Expression '&' has an invalid type or reference

What causes this issue?

You have entered the expression &V1&. This has a data type reference
that cannot accept organizational objects.

System Response

The expression is not permitted by the system.

How to fix this error?

Use an expression that can accept organizational objects.

Procedure for System Administrators

Use an ABAP Dictionary reference that refers to the domain
<AB>HROBJEC_14</> as data type reference for the expression.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message WD288 - Expression '&' has an invalid type or reference ?

  The SAP error message:
  WD288 Expression '&' has an invalid type or reference
  typically occurs in the context of Web Dynpro ABAP development, specifically when there is an issue with an expression used in the UI element properties, context bindings, or in the code where an expression is evaluated.
  
  Cause
  
  The error indicates that the expression containing the character & (ampersand) is invalid due to:
  
  Incorrect syntax in the expression.
  Use of an invalid or undefined reference (e.g., a context attribute or variable that does not exist or is not accessible).
  The expression is expected to be of a certain data type, but the actual type is incompatible.
  The & character is often used in expressions for concatenation or as a placeholder, but if used incorrectly, it causes this error.
  
  
  
  In Web Dynpro ABAP, expressions are used in property bindings or in the IF_WD_CONTEXT_ELEMENT~GET_ATTRIBUTE method, and the expression parser expects valid references and types.
  
  Typical Scenarios
  
  Using & in an expression where it is not allowed or without proper context.
  Binding a UI element property to an expression that references a context attribute incorrectly.
  Typo in the attribute name or missing context node/attribute.
  Trying to concatenate strings or variables incorrectly in the expression.
  
  
  Solution
  
  
  Check the Expression Syntax:
  
  Verify that the expression is syntactically correct.
  In Web Dynpro, expressions should follow the correct syntax, e.g., context_node.attribute or use the expression editor.
  
  
  
  Validate References:
  
  Ensure that all context nodes and attributes referenced in the expression exist.
  Check spelling and case sensitivity.
  
  
  
  Correct Use of &:
  
  If you are trying to concatenate strings, use the proper syntax.
  In Web Dynpro ABAP expressions, concatenation is usually done by the CONCATENATE statement in ABAP code, not by & in expressions.
  If you want to use & as a literal character, escape it properly or avoid using it in expressions.
  
  
  
  Use Expression Editor:
  
  Use the Web Dynpro expression editor to build expressions rather than typing manually.
  This helps avoid syntax errors and invalid references.
  
  
  
  Check Data Types:
  
  Make sure the expression returns the expected data type.
  For example, if a property expects a string, the expression should evaluate to a string.
  
  
  
  Debugging:
  
  Use the Web Dynpro debugger or add breakpoints to check the values and references at runtime.
  Check the context structure in the Web Dynpro Explorer.
  
  
  
  
  Related Information
  
  
  SAP Note / Documentation:
  
  Check SAP Help Portal for Web Dynpro ABAP expressions.
  SAP Community forums often discuss similar issues with expression errors.
  
  
  
  Expression Syntax in Web Dynpro:
  
  Expressions are used for property bindings, visibility, enablement, etc.
  They must reference valid context attributes or constants.
  
  
  
  Example:
  Incorrect expression causing error:
  &context_node.attribute&
  Correct usage:
  context_node.attribute
  Or in ABAP code:
  CONCATENATE var1 var2 INTO result.
  
  
  
  Summary
  
  
  
  Aspect
  Details
  
  
  
  
  Cause
  Invalid expression syntax or invalid reference involving & in Web Dynpro ABAP expression.
  
  
  Solution
  Correct the expression syntax, validate references, avoid improper use of &, use expression editor.
  
  
  Related
  Web Dynpro ABAP expression syntax, context node/attribute validation, SAP Help and Notes.
  
  
  
  
  If you provide the exact expression or context where the error occurs, I can help you correct it specifically.