CODEWITHSUNDEEP
c#outlookvsto
DWE
DWE

Reputation: 137

Outlook VSTO - testing whether a property exists, prior to attempting to get the property through the PropertyAccessor

Is there a means of testing whether a property exists, prior to attempting to get the property through the PropertyAccessor?

I utilise the function below, using the Outlook PropertyAccessor, to return a string value of a property. If the property doesn't exist, the function catches the error and returns a null value string. I write out the error using the debug.writeline method to visibly identify what error is thrown - the only error that I really come across is Exception thrown: 'System.Runtime.InteropServices.COMException and that usually is related to the property being unknown or cannot be found. The DASL being passed and property names are correct and work - however not all emails have these properties - they are created by an independent software vendor.

    ...
    using Outlook = Microsoft.Office.Interop.Outlook;
    ...
    private string GetPropertyString(Outlook.PropertyAccessor pa, string property)
    {
        string retVal = null;

        try
        {
            retVal = (string)pa.GetProperty(property);
        }
        catch (Exception ex)
        {
            retVal = null;
            Debug.WriteLine("OutlookProperties - GetPropertyString() - Error:=" + ex.Message);
            //throw;
        }
        finally
        {

        }
        return retVal;
    }

When a property does not exist, an exception is thrown, and whilst it is caught, it doesn't seem to be (properly)handled - the output being:

Exception thrown: 'System.Runtime.InteropServices.COMException' in Office777.dll

OutlookProperties - GetPropertyString() - Error:=The property "http://schemas.microsoft.com/mapi/string/{41FFBD02-4241-4EBD-A7B3-93DD2DF86CA9}/CaseGUID" is unknown or cannot be found.

Many thanks in Advance

Upvotes: 1

Views: 461

Answers (1)

Dmitry Streblechenko
Dmitry Streblechenko

Reputation: 66276

Handling the exception is the only way - older versions of Outlook used to return null, but the latest versions always throw the exception. Checking COMException.ErrorCode won't help either: it is usually 0x80020009 (DISP_E_EXCEPTION) rather than something more informative, like MAPI_E_NOT_FOUND.

Upvotes: 2

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