In WPF telerik control RadColorPicker, can't apply black color, if the color already selected is null

[Randeep]

We are using WPF telerik control RadColorPicker. In the beginning, we choose to set null color for the entity. The problem is, this null color is being treated as black color by the RadColorPicker and so we can't apply a black color immidiately. Refer to the working code below

XAML:

<telerik:RadColorPicker x:Name="radColorPicker" IsRecentColorsActive="True" SelectedColor="{Binding Path=MyColor}" SelectedColorChanged="radColorPicker_SelectedColorChanged">
<telerik:RadColorPicker.ContentTemplate>
<DataTemplate>
<Rectangle MinWidth="40" MinHeight="20">
<Rectangle.Fill>
<SolidColorBrush Color="{Binding ElementName=radColorPicker, Path=SelectedColor, Mode=TwoWay}"/>
</Rectangle.Fill>
</Rectangle>
</DataTemplate>
</telerik:RadColorPicker.ContentTemplate>
</telerik:RadColorPicker>

Code Behind/View Model:

public Window9()
{
InitializeComponent();
this.DataContext = this;

MyColor = null; // I can't apply a black color in this case because null is being treated as black color
//MyColor = "Red"; // I can apply a black color, when the already applied color is red.
}

private void radColorPicker_SelectedColorChanged(object sender, EventArgs e)
{
MessageBox.Show("Color changed!");
}

public string MyColor { get; set; }

 

However, if I would choose some other color than black, say Red, then after that I am able to apply a black color or if we by default set a red color first as shown in the code, then also we would be able to set a black color.
How to make RadColorPicker treat null color as null only and not black, so that we can apply black color immidiately.​

 

[Petar Mladenov]

Hi Randeep,

You are binding the SelectedColor property (of type Color) of the RadColorPicker to string property from your Main View.
The built-in WPF converters kick in because of the XAML binding you use and convert the string.Empty and the null to Black Color. However, to better represent null color I would suggest the following:

-instead of string in the model, use Color:

public Color MyColor { get; set; }

- initialize the start color with this contructor:

MyColor = Color.FromArgb(0, 0, 0 , 0);

This way when you change the color to black runtime, the SelectedColor will be successfully set to Black.

Regards,
Petar Mladenov
Telerik