'Graying Out' a WPF button image?

I have a simple Button control that contains an Image object as its content. I want so set the Image opacity to 0.5 when the Button is disabled to provide an additional visual cue as to the Button status.

What is the simplest way to accomplish that re开发者_运维百科sult in XAML? Thanks for your help.

---

Use a trigger in the Image style. (It would be more natural to put it in the Button style, but the Button style can't easily affect the Image for annoying technical reasons. It could be done in the Button's ControlTemplate but that's overkill for what you want here.)

<Button>
  <Image Source="something.png">
    <Image.Style>
      <Style TargetType="Image">
        <Style.Triggers>
          <Trigger Property="IsEnabled" Value="False">
            <Setter Property="Opacity" Value="0.5" />
          </Trigger>
        </Style.Triggers>
      </Style>
    </Image.Style>
  </Image>
</Button>

Note we are taking advantage here of the fact that the Image will be disabled when the Button is disabled, so we can trigger directly on the Image's own IsEnabled property. In other cases, the Button property we want to trigger on might not be inherited by the Image; in that case, we'd need to use a DataTrigger with the FindAncestor RelativeSource to bind to the containing button.

---

If you want something more generic, put this in your resources section for your window or UserControl .

<UserControl.Resources>     
    <Style x:Key="ImageEnabled" TargetType="Image">
        <Style.Triggers>
            <Trigger Property="IsEnabled" Value="False">
                <Setter Property="Opacity" Value="0.25"></Setter>
            </Trigger>
        </Style.Triggers>
    </Style>
</UserControl.Resources>

And in the actual button just do this

<Button>
    <Image Source="{StaticResource LinkImage}" Style="{StaticResource ImageEnabled}"/>
</Button>

---

Here's a more generic style you can apply:

<Style TargetType="Button">
    <Style.Resources>
        <Style TargetType="Image">
            <Style.Triggers>
                <Trigger Property="IsEnabled" Value="False">
                    <Setter Property="Opacity" Value="0.5" />
                </Trigger>
            </Style.Triggers>
        </Style>
    </Style.Resources>
</Style>

---

If you want the entire button greyed out, styling the button itself has worked for me. It seems to grey out all button content.

                    <Button.Style>
                        <Style TargetType="Button">
                            <Style.Triggers>
                                <Trigger Property="IsEnabled" Value="False">
                                    <Setter Property="Opacity" Value=".75"/>
                                </Trigger>
                            </Style.Triggers>
                        </Style>
                    </Button.Style>

---

previous solutions only change opacity and not the color of the image, to gray out an image one need to convert the image to grayscale as follow. I did it for a toggleButton but the same method can be used on a button.

<ToggleButton>
    <ToggleButton.Style>
        <Style TargetType="{x:Type ToggleButton}">
           <Setter Property="Content">
               <Setter.Value>
                    <Image
                         RenderOptions.BitmapScalingMode="HighQuality"
                         RenderOptions.EdgeMode="Aliased"
                         Source="/Resources/imageForButton.png"
                         Stretch="UniformToFill" />
                 </Setter.Value>
             </Setter>
             <Style.Triggers>
                 <Trigger Property="IsChecked" Value="False">
                     <Setter Property="Content">
                         <Setter.Value>
                             <Image
                               RenderOptions.BitmapScalingMode="HighQuality"
                               RenderOptions.EdgeMode="Aliased"
                               Stretch="UniformToFill">
                                 <Image.Source>
                                    <FormatConvertedBitmap
                                       x:Name="myImageFormat"
                                       DestinationFormat="Gray8"
                                       Source="/Resources/imageForButton.png" />
                                 </Image.Source>
                             </Image>
                       </Setter.Value>
                </Setter>
             </Trigger>
          </Style.Triggers>
       </Style>
    </ToggleButton.Style>
</ToggleButton>