CODEWITHSUNDEEP
c#winformscustom-controls
TeamWild
TeamWild

Reputation: 2550

How to expose events in a WinForms custom control

I've developed a custom control that acts like a group box with a check box over the group label. The idea being, once the check box is unchecked all the controls in the group are disabled.

I need to expose the Check changed event so that external actions could be performed if required. I've also exposed the Check state changed.

Currently, when the control is used it changes the check state when any of the controls in the group loose focus.

When I handle the check changed event, should I then re-fire the event for any external handlers?

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The events defined:

/// <summary>
/// Event to forward the change in checked flag
/// </summary>
public event EventHandler CheckedChanged;

/// <summary>
/// Event to forward the change in checked state of the checkbox
/// </summary>
public event EventHandler CheckStateChanged;

The event handler code:

private void chkBox_CheckedChanged(object sender, EventArgs e)
{
    // Disable the controls within the group
    foreach( Control ctrl in this.Controls )
    {
        if( ctrl.Name != "chkBox" && ctrl.Name != "lblDisplay" )
        {
            ctrl.Enabled = this.chkBox.Checked;
        }
    }

    // Now forward the Event from the checkbox
    if (this.CheckedChanged != null)
    {
        this.CheckedChanged(sender, e);
    }
}

private void chkBox_CheckStateChanged(object sender, EventArgs e)
{
    // Forward the Event from the checkbox
    if( this.CheckStateChanged != null )
    {
        this.CheckStateChanged( sender, e );
    }
}

Upvotes: 0

Views: 2126

Answers (1)

CharithJ
CharithJ

Reputation: 47570

You are almost there. You just have to register your event with a event handler in external class.

CheckedChanged += ExternalChkBox_CheckChanged;

private void ExternalChkBox_CheckChanged(object sender, EventArgs e)
{
    // External trigger
}

Upvotes: 1

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