WPF. Must have non-null value for 'Property' for multitrigger condition

Question

Have multitrigger, one of the conditions is not null, so if StowedAssetDetailedThumbnailViewModel != null then set template

<Style.Triggers>
    <MultiTrigger>
        <MultiTrigger.Conditions>
            <Condition Property="IsSelected" Value="true" />
            <Condition Binding="{Binding Path=StowedAssetDetailedThumbnailViewModel,
                                         Converter={StaticResource isNull}}"
                       Value="False"/>
        </MultiTrigger.Conditions>
        <Setter Property="Template" Value="{StaticResource SelectedTemplate}" />
    </MultiTrigger>
</Style.Triggers>

Using simple converter:

return isNull == null;

the error is Must have non-null value for Property

UPDATE: Thanks, the final solution is

<Style.Triggers>
    <MultiDataTrigger>
        <MultiDataTrigger.Conditions>
            <Condition Binding="{Binding IsSelected, RelativeSource={RelativeSource Self}}"
                       Value="true" />
            <Condition Binding="{Binding Path=StowedAssetDetailedThumbnailViewModel,
                                 Converter={StaticResource isNull}}"
                                 Value="false"/>
        </MultiDataTrigger.Conditions>

        <Setter Property="Template" Value="{StaticResource SelectedTemplate}" />
    </MultiDataTrigger>
</Style.Triggers>

Is it your custom control? – JleruOHeP Jan 13 '14 at 05:57 — JleruOHeP, Jan 13 '14 at 05:57

score 48 · Accepted Answer · answered Jan 13 '14 at 06:02

48

You'll want to use a MultiDataTrigger in this case. A MultiTrigger can only be triggered by dependency properties.

answered Jan 13 '14 at 06:02

Patrick Y

763
7
10

4

The converse appears to be true as well... if triggering on DPs, you can only use `MultiTrigger`. – Robert Gowland Nov 07 '14 at 14:45
At least in some situations. – Robert Gowland Nov 07 '14 at 15:37

WPF. Must have non-null value for 'Property' for multitrigger condition

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