IExpressionEval::ParseXML
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Use this method to check whether an Extensible Markup Language (XML) fragment is a syntactically correct expression.
Definition
HRESULT IExpressionEval::ParseXML(BSTRbstrXMLExpr,VARIANT_BOOL*pbValid);
Parameters
bstrXMLExpr
[in] A BSTR that contains the XML text defining an expression.
pbValid
[out, retval] A pointer to a VARIANT_BOOL indicating the validity of the expression.
Return Values
This method returns an HRESULT indicating whether it completed successfully. See the Error Values section for more details.
Error Values
This method returns S_OK (0x00000000) to indicate success and either standard or custom COM HRESULT error values to indicate failure. For more information about standard COM errors, see Standard COM Errors.
The following table shows the custom COM errors that this method can return.
| Constant | Value | Description |
| E_EXPR_BADARGTYPE | 0x81100018 | Argument datatype information missing from expression, or unrecognized argument data type encountered in expression |
| E_EXPR_BADARGVALUE | 0x81100022 | Invalid expression argument value, or impossible conversion |
| E_EXPR_BADCLAUSE | 0x81100016 | Invalid clause encountered |
| E_EXPR_BADOPER | 0x81100017 | Operator missing, unrecognized operator encountered, or type mismatch |
| E_EXPR_BADTERM | 0x81100015 | Term type missing, or unrecognized term type encountered |
| E_EXPR_BADXML | 0x81100014 | An unrecognized XML element was encountered |
| E_EXPR_XMLPARSE | 0x81100013 | XML DOM object parsing error |
Additional information may be available using the global Err object, which can be accessed using the API function GetErrorInfo. In particular, the GetDescription method of the IErrorInfo interface may return a text description of the error.
Remarks
Since this method only checks syntax, the expression may still be invalid even though the method succeeds.
The expression store is not used for XML fragments.
For more information about memory ownership issues related to COM property and method parameters, see Managing COM Parameter Memory.
The pbValid parameter contains valid data only if the method completes successfully.