Processing Command Clicks

Command clicks can occur from several situations. One is when a button command link is clicked or one of its keyboard shortcuts is pressed. Another is if a custom control's (such as a textbox or combobox) value changes and is committed.

There currently are two ways to handle and process command clicks.

Handling the BarManager.CommandClick Event

This method of processing command clicks is similar to a "dispatch" type of method. Basically, you handle the CommandClick event exposed by the BarManager and in it, use a large switch statement to forward command processing to other methods. Or you can handle the processing directly in the event handler itself.

The CommandClick event arguments indicate which BarCommand should be processed. They also will pass which BarCommandLink was clicked if the click originated from the user interface.

This sample demonstrates how to handle command clicks using this approach:

/// <summary>
/// Occurs when a <see cref="BarCommand"/> is clicked.
/// </summary>
/// <param name="sender">Sender of the event.</param>
/// <param name="e">Event arguments.</param>
private void barManager_CommandClick(object sender, ActiproSoftware.UI.WinForms.Controls.Bars.BarCommandLinkEventArgs e) {
	switch (e.Command.FullName) {
		case "File.New":
			this.ProcessFileNew();
			break;
		case "File.Exit":
			this.ProcessFileExit();
			break;
	}
}

Overriding Command Classes

Another option, which is much more advanced, is to create a command class for each command. For instance, you could make a FileNewCommand that inherits BarButtonCommand. Then you would place all your code for "File.New" in the override of the OnClick method.

This sample demonstrates how to handle command clicks using this approach:

public class FileNewCommand : BarButtonCommand {

	/// <summary>
	/// Initializes a new instance of the <c>FileNewCommand</c> class.
	/// </summary>
	/// <param name="category">The category of the bar command.</param>
	/// <param name="name">The name of the bar command.</param>
	/// <param name="text">The text caption.</param>
	/// <param name="imageIndex">The index of an image within an <c>ImageList</c>.</param>
	public FileNewCommand(string category, string name, string text, int imageIndex) :
		base(category, name, text, imageIndex) {}

	/// <summary>
	/// Raises the <c>Click</c> event.
	/// </summary>
	/// <param name="e">A <c>BarCommandLinkEventArgs</c> that contains the event data.</param>
	protected override void OnClick(BarCommandLinkEventArgs e) {
		// Get some sort of pre-set context object from the BarManager's Tag property
		BarForm.BarFormContext context = (BarForm.BarFormContext)e.BarManager.Tag;

		// NOTE: Create a new document here
	}
}

The downside to this method is that there is no designer-oriented way to swap the normal command with your custom command type. However, you can modify the InitializeComponent code directly to make the switch.

To make the switch you'd change this line...

ActiproSoftware.UI.WinForms.Controls.Bars.BarButtonCommand fileNewBarButtonCommand =
	new ActiproSoftware.UI.WinForms.Controls.Bars.BarButtonCommand("File", "New", "&New...", -1);

To this:

MyNamespace.FileNewCommand fileNewBarButtonCommand = new MyNamespace.FileNewCommand("File", "New", "&New...", -1);

Once that code is in place, the designer should remember to code serialize your class.