topic Type conversion? in ArcObjects SDK Questions

'Error HRESULT E_FAIL has been returned from a call to a COM component' get selected.

kju — Mon, 04 Nov 2013 15:39:15 GMT

Post my code at first:

 #region Member.
        private AxMapControl _MapCon = null;    //MapControl from the main form.
        private IGeometry _BufferResult = null;
        #endregion
        public FrmBufferAnalyst(AxMapControl mapControl) {
            this._MapCon = mapControl;
            InitializeComponent();
        }
        private void FrmBufferAnalyst_Load(object sender, EventArgs e) {
            ShowSelectedFeatures();
        }
        /// <summary>
        /// //Show selected feature.
        /// </summary>
        void ShowSelectedFeatures() {
            lbox_selectedFeature.Items.Clear();
            ISelection fSelection = this._MapCon.Map.FeatureSelection;
            IEnumFeature enumF = (IEnumFeature)fSelection;
            IFeature f = null;
            while((f = enumF.Next()) != null) {
                lbox_selectedFeature.Items.Add("Feature layer:" + f.Class.AliasName);
                lbox_selectedFeature.Items.Add("OID:" + f.OID);
                lbox_selectedFeature.Items.Add("-----");    //Separator.
            }
        }

Before,I used the same project to execute buffer analyst,such as compute the area or query feature within the buffered feature.It works well.
But now,when I select the specifed feature and past them into another form and load.But it throws exception when trying to get the 'OID' property.Is something wrong with my code?Thanks.

Type conversion?

DuncanHornby — Mon, 04 Nov 2013 20:36:20 GMT

If the error is occurring on the line:

lbox_selectedFeature.Items.Add("OID:" + f.OID);

Then it may be a type conversion error as OID will return an Integer. SO in VB I would do something like:

lbox_selectedFeature.Items.Add("OID:" + f.OID.ToString())

Re: Type conversion?

kju — Tue, 05 Nov 2013 03:44:22 GMT

If the error is occurring on the line:
lbox_selectedFeature.Items.Add("OID:" + f.OID);
Then it may be a type conversion error as OID will return an Integer. SO in VB I would do something like:
lbox_selectedFeature.Items.Add("OID:" + f.OID.ToString())

Thanks for your response but,It shouldn't that issue, 'f.OID' cencerns nothing with the exception.when debuging,'f' exsist but throws exception when get it's OID property.

Re: 'Error HRESULT E_FAIL has been returned from a call to a COM component' get selec

BruceNielsen — Tue, 05 Nov 2013 17:56:19 GMT

Does f.HasOID return True?