Question

I have object with 3 property:

CouldBeWhite bool
CouldBeGreen bool
CouldBeRed bool

    If CouldBeWhite is true, then foreground of row should be white,  if
    CouldBeGreen is true, and CouldBeWhite is false, then row should be
    Green If CouldBeRed is true, and  and CouldBeWhite is false and
    CouldBeGreen is false then row should be Red In other case row
    should be blue.

My idea now is to have some new property at viewmodel Color, when I would count color of row.

Or maybe there is some nicer way to implement this?

Answer 1

Add this enum to your project:-

public enum RowState
{
     Blue,
     Red,
     Green,
     White
}

Then add this property to your ViewModel:-

private RowState _RowState;
public RowState RowState
{
     get { return _RowState; }
     set
     {
         if (value != _RowState)
         {
               _RowState = value;
               NotifyPropertyChanged("RowState"); // Assumes typical implementation of INotifyPropertyChanged 
         }
     }
}

private void UpdateRowState()
{
    if (CouldBeWhite)
         RowState = RowState.White;
    else if (CouldBeGreen)
         RowState = RowState.Green;
    else if (CouldBeRed)
         RowState = RowState.Red;
    else
         RowState = RowState.Blue;
}

Call UpdateRowState when every the CouldBeXXX properties change.

Consider that you are probably not making the foreground white or red or green just as a whim. There will be be some reason why its white, red or green. So in your code think of a simple short name to represent those reasons and replace the color names with those more meaningful names.

Now go fetch the code for StringToValueConverter in this blog. Add an instance of this to your Xaml in the UserControl.Resources:

         <local:StringToObjectConverter x:Key="RowStateToBrush">
             <ResourceDictionary>
                 <SolidColorBrush Color="Red" x:Key="Red" />
                 <SolidColorBrush Color="Green" x:Key="Green" />
                 <SolidColorBrush Color="White" x:Key="White" />
                 <SolidColorBrush Color="Blue" x:Key="__default__" /> 
            </ResourceDictionary>
         </local:StringToObjectConverter>

You can bind on a TextBlock:

  <TextBlock Text="{Binding SomeTextProperty}"  Foreground="{Binding RowState, Converter={StaticResource RowStateToBrush}}" />