[wpf] How can I provide multiple conditions for data trigger in WPF?

THIS ANSWER IS FOR ANIMATIONS ONLY


If you wanna implement the AND logic, you should use MultiTrigger, here is an example:

Suppose we want to do some actions if the property Text="" (empty string) AND IsKeyboardFocused="False", then your code should look like the following:

<MultiTrigger>
    <MultiTrigger.Conditions>
        <Condition Property="Text" Value="" />
        <Condition Property="IsKeyboardFocused" Value="False" />
    </MultiTrigger.Conditions>
        <MultiTrigger.EnterActions>
            <!-- Your actions here -->
        </MultiTrigger.EnterActions>
</MultiTrigger>

If you wanna implement the OR logic, there are couple of ways, and it depends on what you try to do:

The first option is to use multiple Triggers.
So, suppose you wanna do something if either Text="" OR IsKeyboardFocused="False",
then your code should look something like this:

<Trigger Property="IsEnabled" Value="false">
    <Setter Property="Opacity" TargetName="border" Value="0.56"/>
</Trigger>
<Trigger Property="IsMouseOver" Value="true">
    <Setter Property="BorderBrush" TargetName="border" 
            Value="{StaticResource TextBox.MouseOver.Border}"/>
</Trigger>

But the problem in this is what will I do if i wanna do something if either Text ISN'T null OR IsKeyboard="True"? This can be achieved by the second approach:
Recall De Morgan's rule, that says !(!x && !y) = x || y.
So we'll use it to solve the previous problem, by writing a multi trigger that it's triggered when Text="" and IsKeyboard="True", and we'll do our actions in EXIT ACTIONS, like this:

<MultiTrigger>
    <MultiTrigger.Conditions>
        <Condition Property="Text" Value="" />
        <Condition Property="IsKeyboardFocused" Value="False" />
    </MultiTrigger.Conditions>
    <MultiTrigger.ExitActions>
        <!-- Do something here -->
    </MultiTrigger.ExitActions>
</MultiTrigger>