How to change button's image source programmatically?

Question

I have a button like this:

<Button Name="Btn_Import"
        Grid.Row="33"
        Grid.Column="15"
        Grid.ColumnSpan="36"
        Grid.RowSpan="36"
        Click="Btn_Import_Click"
        MouseEnter="import_desc"
        MouseLeave="desc_clear">
    <Button.Template>
        <ControlTemplate>
            <Grid RenderTransformOrigin="0.5,0.5"
                  x:Name="bg">
                <Image Name="import_image"
                       Source="/Images/01_Main_Screen/MS_START_IMPORT_NORMAL.png" />
            </Grid>
            <ControlTemplate.Triggers>
                <Trigger Property="IsMouseOver"
                         Value="True">
                    <!-- hover effect -->
                    <Setter TargetName="import_image"
                            Property="Source"
                            Value="/Images/01_Main_Screen/MS_START_IMPORT_OVER.png" />
                </Trigger>
                <Trigger Property="Button.IsPressed"
                         Value="True">
                    <!-- press effect -->
                    <Setter TargetName="bg"
                            Property="RenderTransform">
                        <Setter.Value>
                            <ScaleTransform ScaleX="0.9"
                                            ScaleY="0.9" />
                        </Setter.Value>
                    </Setter>
                </Trigger>
            </ControlTemplate.Triggers>
        </ControlTemplate>
    </Button.Template>
    <Button.Style>
        <!-- initially disabled-->
        <Style TargetType="Button">
            <!--<Setter Property="IsEnabled" Value="False" />-->
            <!--<Setter Property="Opacity" Value="0.3" />-->
        </Style>
    </Button.Style>
</Button>

And then at some point in code behind, I locally change its image source to something else like this:

ControlTemplate ct1 = Btn_Import.Template;
Image btnImage1 = (Image)ct1.FindName("import_image", Btn_Import);
btnImage1.Source = new BitmapImage(new Uri("/Images/01_Main_Screen/MS_START_IMPORT_FINISH.png", UriKind.RelativeOrAbsolute));

After doing this, I lose the 'mouse over' effect probably because I overwrite the original button's template. How to locally again 'tell' the button to trigger on mouse over? Or in other words, how to write this in C#:

<ControlTemplate.Triggers>
    <Trigger Property="IsMouseOver" 
          Value="True">
     <!-- hover effect -->
     <Setter TargetName="import_image" Property="Source"
             Value="/Images/01_Main_Screen/MS_START_IMPORT_OVER.png" />
    </Trigger>

Use data binding instead of code-behind. It's how WPF was designed to be used and why you run into countless problems just like this when you try to do things the old WinForms way. — Mark Feldman
– Mark Feldman, Commented Oct 5, 2015 at 10:27
Once you set the Source on the Button, you are setting the local value of the Button's Sourceproperty, which is a DependencyProperty (Button.SourceProperty). The local value overrides any other possible value until it is cleared. — martinm
– martinm, Commented Oct 5, 2015 at 10:39

AnjumSKhan · Accepted Answer · 2015-10-05 10:45:38Z

It is probably because of property value precedence. I have added some resources in your template. Now when you want to change some source value, do it by accessing the resource.

Also note that for binding to our resources we are using DynamicResource otherwise any code level changes won't be visible.

Below changes are working like a breeze.

<Button.Template>
                <ControlTemplate>

                    <ControlTemplate.Resources>
                        <Image x:Key="NORMAL" Source="images/01_Main_Screen/MS_START_IMPORT_NORMAL.png"/>
                        <Image x:Key="OVER" Source="images/01_Main_Screen/MS_START_IMPORT_OVER.png"/>
                    </ControlTemplate.Resources>

                    <Grid RenderTransformOrigin="0.5,0.5"
                  x:Name="bg">
                        <Label x:Name="import_image" Content="{DynamicResource NORMAL}" HorizontalContentAlignment="Center" HorizontalAlignment="Stretch"/>                        
                    </Grid>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsMouseOver"
                         Value="True">
                            <!-- hover effect -->
                            <Setter TargetName="import_image"
                            Property="Content"
                            Value="{DynamicResource OVER}" />
                            <Setter TargetName="bg"
                            Property="Background"
                            Value="Purple" />
                        </Trigger>
                        <Trigger Property="Button.IsPressed"
                         Value="True">
                            <!-- press effect -->
                            <Setter TargetName="bg"
                            Property="RenderTransform">
                                <Setter.Value>
                                    <ScaleTransform ScaleX="0.9"
                                            ScaleY="0.9" />
                                </Setter.Value>
                            </Setter>
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Button.Template>

Then in code,

ControlTemplate ct1 = Btn_Import.Template;
Image normalImage = (Image)ct1.Resources["NORMAL"];
normalImage.Source = new BitmapImage(new Uri("Images/01_Main_Screen/MS_START_IMPORT_FINISH.png", UriKind.RelativeOrAbsolute));

note that if you are not changing source of images, then you can also use ImageBrush, as Brushes won't allow themselves to be changed in code.

Collectives™ on Stack Overflow

How to change button's image source programmatically?

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related