CODEWITHSUNDEEP
mvvm
user3502966
user3502966

Reputation: 59

mvvm:How should i bind boolean value to combobox

I am doing an application in MVVM and I am new at it... I have a boolean field and want to show a combobox to user with items Yes/No but when user selects it, but in data context values are 1 and 0. i have the following code:

<TextBlock Grid.Row="2" Grid.Column="2" Text="Batch Flag" Margin="5,0,0,0" />
                                <ComboBox Grid.Row="2" Grid.Column="3" x:Name="cboBtchFlg" SelectedItem="{Binding SelectedADM_M022.BtchFlg,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"  Margin="5,0,0,2" Background="Transparent">
                                    <ComboBoxItem Tag="1">True</ComboBoxItem>
                                    <ComboBoxItem Tag="0">False</ComboBoxItem>
                                </ComboBox>

Upvotes: 2

Views: 1377

Answers (1)

Mal
Mal

Reputation: 441

You could use a converter. If the view model property is a bool, and this is bound to the SelectedIndex property of your combobox, which is an int, then this example will provide what you need.

public class IntToBoolConverter : IValueConverter
{
    // from view model to view
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        if (value is bool)
        {
            bool trueFalse = (bool)value;
            return trueFalse == true ? 0 : 1;
        }
        return value;
    }

    // from view to model
    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        if (value is int)
        {
            int index = (int)value;
            if (index == 0)
                return true;
            if (index == 1)
                return false;
        }
        return value;
    }
}

Amend the SelectedIndex binding to

SelectedItem="{Binding SelectedADM_M022.BtchFlg,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged, Converter={StaticResource boolConverter}}"

given you have a resource called boolConverter that references your converter class e,g,

<Window.Resources>
    <local:IntToBoolConverter x:Key="boolConverter" />
</Window.Resources>

Upvotes: 2

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