How do I get a reference to another control?

[Daniel_HjorthChristensen1]

Let's say I have the following simple case: 

I have a combobox and a button. When I press the button, I want to display the selected item from the combobox in a messagebox.

How do I, from the button click event handler, access the items and selected item from the combobox?

I have tried the pluginwrapper, but that only permits access to DAML properties (i.e. caption etc.). It is frustrating because when debugging, I can see a reference to the combobox, but it is private and cannot be accessed. I have tried casting the pluginwrapper and I have failed to find any way of unwrapping it.

I further tried to use DAML categories and Categories.GetComponentElements, however I don't get anything back there.

Full source attached (it's very simple code).

• Am I using categories wrong? If so, how?
• What is the right way to access elements of another control?  (either as e.g. ComboBox, or even better as the implementation ComboBox1 or whatever it may be called).

[Wolf]

Hi Daniel,

 One common pattern is to use the Module1 class to hold your selected values and allow other controls to access the value through the Module1 class (which is a singleton).  So in your example you need to add a public property, which I call 'MyComboboxValue', to the Module1 class in order to hold the combobox selection:

internal class Module1 : Module
{
  private static Module1 _this = null;

  /// <summary>
  /// Retrieve the singleton instance to this module here
  /// </summary>
  public static Module1 Current
  {
...
  }
 
  // Add your 'shared' properties here:
  public string MyComboboxValue { get; set; }

...
}‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Now you need to store the ComboBox selection by modifying the ComboBox1 class' OnSelectionChange method:

/// <summary>
/// The on comboBox selection change event. 
/// </summary>
/// <param name="item">The newly selected combo box item</param>
protected override void OnSelectionChange(ComboBoxItem item)
{
  if (item == null) return;

  // save the selection in your module1 class
  Module1.Current.MyComboboxValue = item.Text;
}‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Finally you can use the 'shared' property throughout your add-in by using the Modul1 class' Current member: Module1.Current.MyComboboxValue.  For example:

MessageBox.Show($@"From Combo Box: {Module1.Current.MyComboboxValue}");‍‍

If you need to access any values from another add-in you can use a Pro FrameworkApplication function to get the Module1 instance like this:

((Module1)FrameworkApplication.FindModule("ProAppModule1_Module")).MyComboboxValue‍‍

Hope this helps