How can I provide multiple conditions for data trigger in WPF

Question

User · Answer

jasonk - if you want to have  or  then negate all conditions since  A and B   lt       A or  B   but if you have values other than boolean try using type converters    lt MultiDataTrigger Conditions gt       lt Condition Value  True  gt           lt Condition Binding gt               lt MultiBinding Converter   StaticResource conditionConverter   gt                   lt Binding Path  Name    gt                   lt Binding Path  State    gt               lt  MultiBinding gt           lt  Condition Binding gt           lt Setter Property  Background  Value  Cyan    gt       lt  Condition gt   lt  MultiDataTrigger Conditions gt    you can use the values in Convert method any way you like to produce a condition which suits you

User · Answer

Use MultiDataTrigger type   lt Style TargetType  ListBoxItem  gt       lt Style Triggers gt         lt DataTrigger Binding   Binding Path State   Value  WA  gt           lt Setter Property  Foreground  Value  Red    gt         lt  DataTrigger gt             lt MultiDataTrigger gt           lt MultiDataTrigger Conditions gt             lt Condition Binding   Binding Path Name   Value  Portland    gt             lt Condition Binding   Binding Path State   Value  OR    gt           lt  MultiDataTrigger Conditions gt           lt Setter Property  Background  Value  Cyan    gt         lt  MultiDataTrigger gt       lt  Style Triggers gt     lt  Style gt

User · Answer

To elaborate on  serine s answer and illustrate working with non-trivial multi-valued condition  I had a need to show a  quot dim-out quot  overlay on an item for the boolean condition NOT a AND  b OR NOT c    For background  this is a  quot Multiple Choice quot  question  If the user picks a wrong answer it becomes disabled  dimmed out and cannot be selected again   An automated agent has the ability to focus on any particular choice to give an explanation  border highlighted   When the agent focuses on an item  it should not be dimmed out even if it is disabled  All items that are not in focused are marked de-focused  and should be dimmed out  The logic for dimming is thus  NOT IsFocused AND  IsDefocused OR NOT Enabled   To implement this logic  I made a generic IMultiValueConverter named  awkwardly  to match my logic     P  represents a parenthesis           a  amp  amp     b        c   class NOT a AND P b OR NOT c P   IMultiValueConverter          redacted       for brevity     public object Convert object   values                     bool a   System Convert ToBoolean values 0            bool b   System Convert ToBoolean values 1            bool c   System Convert ToBoolean values 2             return  a  amp  amp   b     c                    In the XAML I use this in a MultiDataTrigger in a  lt Style gt  lt Style Triggers gt  resource  lt MultiDataTrigger gt       lt MultiDataTrigger Conditions gt           lt  -- when the equation is TRUE     -- gt           lt Condition Value  quot True quot  gt               lt Condition Binding gt                   lt MultiBinding Converter  quot  StaticResource NOT a AND P b OR NOT c P  quot  gt                       lt  -- NOT IsFocus AND   IsDefocused OR NOT Enabled   -- gt                       lt Binding Path  quot IsFocus quot   gt                       lt Binding Path  quot IsDefocused quot    gt                       lt Binding Path  quot Enabled quot    gt                   lt  MultiBinding gt               lt  Condition Binding gt           lt  Condition gt       lt  MultiDataTrigger Conditions gt       lt MultiDataTrigger Setters gt           lt  --     show the  dim-out  overlay -- gt           lt Setter Property  quot Visibility quot  Value  quot Visible quot    gt       lt  MultiDataTrigger Setters gt   lt  MultiDataTrigger gt   And for completeness sake  my converter is defined in a ResourceDictionary  lt ResourceDictionary xmlns conv  quot clr-namespace My Converters quot      gt       lt conv NOT a AND P b OR NOT c P x Key  quot NOT a AND P b OR NOT c P quot    gt   lt  ResourceDictionary gt

User · Answer

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    lt MultiTrigger gt       lt MultiTrigger Conditions gt           lt Condition Property  Text  Value      gt           lt Condition Property  IsKeyboardFocused  Value  False    gt       lt  MultiTrigger Conditions gt           lt MultiTrigger EnterActions gt               lt  -- Your actions here -- gt           lt  MultiTrigger EnterActions gt   lt  MultiTrigger gt    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    lt Trigger Property  IsEnabled  Value  false  gt       lt Setter Property  Opacity  TargetName  border  Value  0 56   gt   lt  Trigger gt   lt Trigger Property  IsMouseOver  Value  true  gt       lt Setter Property  BorderBrush  TargetName  border               Value   StaticResource TextBox MouseOver Border    gt   lt  Trigger gt     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  amp  amp   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    lt MultiTrigger gt       lt MultiTrigger Conditions gt           lt Condition Property  Text  Value      gt           lt Condition Property  IsKeyboardFocused  Value  False    gt       lt  MultiTrigger Conditions gt       lt MultiTrigger ExitActions gt           lt  -- Do something here -- gt       lt  MultiTrigger ExitActions gt   lt  MultiTrigger gt

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

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