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copied!<p>Just threw a test together, both of these work for me:</p> <p>Using full syntax:</p> <pre><code> <TextBox Name="Threshold" Margin="5" Grid.Column="1"> <i:Interaction.Triggers> <i:EventTrigger EventName="KeyDown"> <cal:ActionMessage MethodName="ExecuteFilterView"> <cal:Parameter Value="$executionContext"/> </cal:ActionMessage> </i:EventTrigger> </i:Interaction.Triggers> </TextBox> </code></pre> <p>Using CM syntax (prefer this as it's way more readable)</p> <pre><code> <TextBox Name="Threshold" Margin="5" Grid.Column="1" cal:Message.Attach="[Event KeyDown] = [Action ExecuteFilterView($executionContext)]" /> </code></pre> <p>This was the test VM:</p> <pre class="lang-cs prettyprint-override"><code>public class MainWindowViewModel { public void ExecuteFilterView(ActionExecutionContext context) { // This method is hit and the context is present and correct } } </code></pre> <p>Can you post your full code - are you sure you have the framework setup correctly? (have you followed the getting started example? </p> <p><a href="http://caliburnmicro.codeplex.com/wikipage?title=Basic%20Configuration%2c%20Actions%20and%20Conventions&referringTitle=Documentation" rel="noreferrer">http://caliburnmicro.codeplex.com/wikipage?title=Basic%20Configuration%2c%20Actions%20and%20Conventions&referringTitle=Documentation</a></p> <p><strong>Edit:</strong></p> <p>Ok after your clarification I can give you some examples of how to do this - I'll tell you my personal preference and why, but choose the one that fits you best</p> <ol> <li>Using <code>ActionExecutionContext</code> and casting the eventargs:</li> </ol> <pre class="lang-xml prettyprint-override"><code> cal:Message.Attach="[Event KeyDown] = [Action ExecuteFilterView($executionContext)]" </code></pre> <pre class="lang-cs prettyprint-override"><code> public void ExecuteFilterView(ActionExecutionContext context) { var keyArgs = context.EventArgs as KeyEventArgs; if (keyArgs != null && keyArgs.Key == Key.Enter) { // Do Stuff } } </code></pre> <ol start="2"> <li>Using <code>EventArgs</code> directly</li> </ol> <pre class="lang-xml prettyprint-override"><code> cal:Message.Attach="[Event KeyDown] = [Action ExecuteFilterView($eventArgs)]" </code></pre> <pre class="lang-cs prettyprint-override"><code> public void ExecuteFilterView(KeyEventArgs keyArgs) { if (keyArgs.Key == Key.Enter) { // Do Stuff } } </code></pre> <ol start="3"> <li>My personal fave, creating your own <code>SpecialValues</code> dictionary entry:</li> </ol> <p>In your <code>Bootstrapper.Configure</code> method...</p> <pre class="lang-cs prettyprint-override"><code>MessageBinder.SpecialValues.Add("$pressedkey", (context) => { // NOTE: IMPORTANT - you MUST add the dictionary key as lowercase as CM // does a ToLower on the param string you add in the action message, in fact ideally // all your param messages should be lowercase just in case. I don't really like this // behaviour but that's how it is! var keyArgs = context.EventArgs as KeyEventArgs; if (keyArgs != null) return keyArgs.Key; return null; }); </code></pre> <p>Your action:</p> <pre><code>cal:Message.Attach="[Event KeyDown] = [Action ExecuteFilterView($pressedKey)]" </code></pre> <p>And the code: </p> <pre class="lang-cs prettyprint-override"><code>public void ExecuteFilterView(Key key) { if (key == Key.Enter) { // Do Stuff } } </code></pre> <p>The reason this is my favourite? It means that your VM just receives the value you want (most of the time you don't care about a lot of the other parameters) and you don't need to know how to or bother to cast the eventargs - you can just operate on the value. Obviously use whatever is best for you</p> <p>It's also worth noting, that if you have other types of controls that subclass <code>KeyEventArgs</code> this will work for them. If they don't subclass <code>KeyEventArgs</code> but they still return a value of type <code>Key</code> this will still work too as you can just add another cast to the delegate if the first one fails:</p> <p>e.g.</p> <pre class="lang-cs prettyprint-override"><code>MessageBinder.SpecialValues.Add("$pressedkey", (context) => { var keyArgs = context.EventArgs as KeyEventArgs; if (keyArgs != null) return keyArgs.Key; // Ok so it wasn't KeyEventArgs... check for some other type - maybe a 3rd party implementation var thirdPartyKeyArgs = context.EventArgs as ThirdPartyKeyArgs; if (thirdPartyKeyArgs != null) return thirdPartyKeyArgs.KeyProperty; return null; }); </code></pre>

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