CODEWITHSUNDEEP
wpfbindingmvvmmvvm-lightwpfdatagrid
katie77
katie77

Reputation: 1813

Using CommandParameters and MultiBindings?

Is it possible to use CommandParameter="{Binding}" in a multi binding? I am trying to do this in a data grid.

<CheckBox.CommandParameter>
    <MultiBinding Converter="{StaticResource CDetailConverter}">
        <Binding Path ="IsChecked" ElementName="chkSelection"/>                                        
        <Binding ConverterParameter="{Binding}"/>
    </MultiBinding>
</CheckBox.CommandParameter>

The second Binding throws an error.

Upvotes: 1

Views: 1340

Answers (1)

RandomActsOfCode
RandomActsOfCode

Reputation: 3285

In a nutshell, the answer is no.

In your second inner Binding you have set ConverterParameter. There are a couple of problems with this:

First, Binding is its own class separate from MultiBinding with both Converter and ConverterParameter properties. Here you have set the ConverterParameter property without setting the Converter property. Remember that ConverterParameter is passed to the Binding's specified converter regardless if it is used within a MultiBinding or not. If you were to add a Converter here, then the converter would be passed the specified ConverterParameter.

What you probably meant to do was set the ConverterParameter on the outer MultiBinding which also has this property:

<CheckBox.CommandParameter>
    <MultiBinding Converter="{StaticResource CDetailConverter}" ConverterParameter="{Binding }">
        <Binding Path ="IsChecked" ElementName="chkSelection"/>                                        
    </MultiBinding>
</CheckBox.CommandParameter>

If you try this, you will quickly see that ConverterParameter can not be the target of a Binding expression since it is not a DependencyProperty.

Since you can not bind to CommandParameter, the typical workaround is to modify your IMultiConverter to accept an additional value, and supply this value through a binding expression:

<CheckBox.CommandParameter>
    <!-- CDetailConverter updated to expect an additional value in the values array -->
    <MultiBinding Converter="{StaticResource CDetailConverter}">
        <Binding Path ="IsChecked" ElementName="chkSelection"/>
        <Binding />                                   
    </MultiBinding>
</CheckBox.CommandParameter>

Hope this helps!

Upvotes: 2

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