Call a parent method from UserControl using WPF in C#

I was implementing some paging functionality in a system I was building and realized that I had created the same forward, backward, first and last buttons and logic 3 times. After doing this I realized these buttons and logic were a perfect example of where I could reduce complexity and encapsulate my code better. I wasn’t able to easily find an example for a situation I ran in to. I needed to call a method from the user control that existed on the parent WPF window. After some trial and error I came up with the below solution.

In the User Control place the below logic.

public event EventHandler ExecuteMethod;
 
protected virtual void OnExecuteMethod()
{
    if (ExecuteMethod != null) ExecuteMethod(this, EventArgs.Empty);
}
 
public void ChildButton_Click(object sender, EventArgs e)
{
    OnExecuteMethod();
}

I first create an event and then a virtual method to call the event. As you can see, when you want to execute an event, you need to pass it the (object, sender) standard parameters. Finally, I had a button in the control, that when pressed would execute the method that in turn executes the event.

In the Parent WPF MainWindow, I added this code:

xmlns:Child="clr-namespace:className;assembly=assemblyName"
 
<Child:className Name="uc_Child" />

Within the opening Window tag, you need to place the reference to your User Control. As well, add it to the references for the project. Then add the tag to your WPF window where you want it displayed.

In the Parent WPF code-behind, MainWindow.xaml.cs, I added this code:

protected void ParentWPF_method(object sender, EventArgs e)
{
   MessageBox.Show("ParentWPF_method called by ChildButton_Click", 
                   "User Control Test", MessageBoxButton.OK, 
                   MessageBoxImage.Asterisk);
}
 
public MainWindow()
{
   InitializeComponent();
 
   uc_Child.ExecuteMethod += new EventHandler(ParentWPF_method);
}  

The ParentWPF_method is the method I want called / executed when the ChildButton_Click occurs. For this example, it simply deploys a messagebox saying that the method was successfully called. In the constructor of the MainWIndow I "wire up" the User Controls’ ExecuteMethod event to the ParentWPF_method function. That is where the magic happens…

I saw a number of other examples that seemed much more complex and others that tightly coupled the user control and parent together. Both things I wanted to avoid when implementing my solution.




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