如何禁用基于 wpf 中其他组合框的组合框

Question

I have 2 combobox in a same wpf window. The first item in first combobox is selectversion and it is selected by default(isselected=true). Now i need the second combobox to be disabled if the first item of first combobox is selected Otherwise enabled.

I tried following,

If(absversion.selectedindex !=0) 

  Secondcombo.isenabled=false://here i am getting null reference exception 

Else
  Secondcombo.isenabled = true:

In page_loaded event I have,

Secondcombo.isenabled = false //so that Secondcombo will be disabled by default wen loaded. 

Could anyone please help me,to get this done.

Answer 1

I'd be more inclined to do this in XAML than in codebehind:

<Grid x:Name="LayoutRoot">
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto" />
        <RowDefinition Height="Auto" />
    </Grid.RowDefinitions>
    <ComboBox Grid.Row="0" x:Name="ComboBox1">
        <ComboBoxItem>Item 1</ComboBoxItem>
        <ComboBoxItem>Item 2</ComboBoxItem>
        <ComboBoxItem>Item 3</ComboBoxItem>
    </ComboBox>
    <ComboBox Grid.Row="1">
        <ComboBox.Style>
            <Style TargetType="{x:Type ComboBox}">
                <Setter Property="IsEnabled" Value="True" />
                <Style.Triggers>
                    <DataTrigger Binding="{Binding ElementName=ComboBox1, Path=SelectedIndex}" Value="0">
                        <Setter Property="IsEnabled" Value="False" />
                    </DataTrigger>
                </Style.Triggers>
            </Style>
        </ComboBox.Style>
        <ComboBoxItem>Item 1</ComboBoxItem>
        <ComboBoxItem>Item 2</ComboBoxItem>
        <ComboBoxItem>Item 3</ComboBoxItem>
    </ComboBox>
</Grid>