Try using this
short iRow = (short)VisRowIndices.visRowFirst;
while (shape.get_CellsSRCExists((short)VisSectionIndices.visSectionProp, iRow, (short)VisCellIndices.visCustPropsValue, (short)0) != 0)
{
string label = shape.get_CellsSRC(
(short)VisSectionIndices.visSectionProp,
iRow,
(short)VisCellIndices.visCustPropsLabel
).get_ResultStr(VisUnitCodes.visNoCast);
string value = shape.get_CellsSRC(
(short)VisSectionIndices.visSectionProp,
iRow,
(short)VisCellIndices.visCustPropsValue
).get_ResultStr(VisUnitCodes.visNoCast);
string strProperties = shape.Name + " - " + label + " - " + value;
Console.WriteLine(strProperties);
iRow++;
}