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[Solved] 4004 error when assigning DataContext -- new for build 1208 not in 1103

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arthurd asked on 11 Dec 2009, 06:53 PM

I was using 2009 3 1103. I just upgraded to 2009 3 1208. Now I get error 4004 InvalidCastException.

I have a grid that is bound to a List<DemographicData> but it actually contains several types of objects whose base class is DemographicsData.

For example:

BaseData
DemographicData derived from BaseData
    PersonalDemographicData derived from DemographicData
    EmployerDemographicData derived from DemographicData
    FamilyDemographicData derived from DemographicData

List<DemographicData> has PersonalDemographicData, EmployerDemographicData , and FamilyDemographicData

Calling "grid.DataContext = demographicdata" now crashes with 4004.

If the List only contains objects of one type (Personal, Employer, or Family) then it works fine. But if you have 2 or more types, it breaks.

The grid has AutoGenerateColumns="False" and the only 2 columns in the grid that are bound are bound to properties of BaseData.

Any ideas?

Looks like the grid is assuming that the object types of all entries must be the same.

[Solved] 4004 error when assigning DataContext -- new for build 1208 not in 1103

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