how to prevent a certain mdichild form from getting focus/activation when switching between other mdichild forms using Ctrl+Tab? C#

Question

In my mdi application i have four mdichild forms, one of them is used as a background and holding some controls..

How to prevent this background mdichild form from getting focus/activation when switching between other mdichild forms using Ctrl+Tab?

In other word how to skip this background mdi child form from the Ctrl+Tab sequence? and also make its z-order to be the last one so that it doesn't hide other mdichild forms when switching between them?

thanks in advance.

Answer 1

By overriding Form.ProcessCmdKey and skip the background form.

    protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
    {
        if ((keyData & Keys.Tab) == Keys.Tab && (keyData & Keys.Control) == Keys.Control)
        {

            Form nextForm = GetNexMdiChildForm();
            if (nextForm != null)
            {
                nextForm.Activate();
                return false;
            }
        }

        return base.ProcessCmdKey(ref msg, keyData);
    }

    private Form GetNexMdiChildForm()
    {
        //get current form index
        Form currentForm = this.ActiveMdiChild;
        int currentFormIndex = Array.IndexOf(this.MdiChildren, currentForm);

        //get next form index
        int nextFormIndex = currentFormIndex + 1;
        if (this.MdiChildren.Length == nextFormIndex)
        {
            nextFormIndex = 0;
        }

        //check if next form is Form 3
        if (this.MdiChildren[nextFormIndex] == background_mdichild_form )
        {
            nextFormIndex++;
            if (this.MdiChildren.Length == nextFormIndex)
            {
                nextFormIndex = 0;
            }
        }
        return MdiChildren[nextFormIndex];
    }