This error says that you try to use a value that is of diffident type than the column's values. If the actual type of the property is a ObservableCollection`1[MarketValueWeb.RateServiceReference.PortfolioInfo]' , then it cannot be treated as a PortfolioInfoExtended оr а string, because comparisons have to be made and those two types don't compare to each other out-of-the-box.
You should ensure the DataType of the bound data is the same as the DataType of the Value you set.
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