C#

Form newForm = (Form) Activator.CreateInstance(Type.GetType(YourNameSpace + "." + YourNewFormName));

Form newForm = (Form) Activator.CreateInstance(Type.GetType(YourNameSpace + "." + YourNewFormName));
newForm.Owner = this;
newForm.Name = YourNewFormName;
newForm.Show();

1. You create a new instance of the form type;
2. You check to see if there is an open form of the same type;
3. If there is, you call the Focus method on the new form instance;

private Form FindOpenFormOfType(Type formType)
{
    foreach (Form form in Application.OpenForms)
    {
        if (form.GetType() == formType)
        {
            return form;
        }
    }
    
    return null;
}

private void klikMenu(object sender, EventArgs e)
{
    string sFormName = "AIO_System." + ((ToolStripMenuItem)sender).Tag.ToString();
    System.Reflection.Assembly asm = System.Reflection.Assembly.GetExecutingAssembly();
    Type formType = asm.GetType(sFormName);
    
    Form frm = FindOpenFormOfType(formType);
    if (frm == null)
    {
        frm = (Form)Activator.CreateInstance(formType);
        frm.Owner = this;
        frm.Show();
    }
    else
    {
        frm.Focus();
    }
}

Richard Deeming wrote:

I suspect that calling Focus on an invisible form causes it to be shown.

BillWoodruff wrote:

all too typical of the so often valueless, poorly written, code samples on MSDN

Dave Kreskowiak wrote:

not seen the "examples" and "documentation" put forth by Telerik and the Kendo UI library

private private Point hitPoint;

private int deleteThreshold = 100;

private void SomeComboBox_SelectedIndexChanged(object sender, EventArgs e)
{
    hitPoint = SomeComboBox.PointToClient(MousePosition);

    // in any "real world" solution, I'd put up a confirmation DialogBox here before allowing a delete
    if(hitPoint.X > deleteThreshold) SomeComboBox.Items.Remove(SomeComboBox.SelectedItem);
}

Member 10413292 wrote:

I like DIY, not just taking.

// define variables to hold calculated
// sizes, and positions for PictureBox
private int pbSizeIncrement = 12;

private Size pbBaseSize;
private Size pbEnterSize;
private Point pbBaseLocation;
private Point pbEnterLocation;

// in your Form's Load EventHandler
// pre-calculate Size, and Location
// for your PictureBox
private void Form1_Load(object sender, EventArgs e)
{
    pbBaseSize = pictureBox1.Size;
    pbEnterSize = new Size(pbBaseSize.Width + pbSizeIncrement, pbBaseSize.Height + pbSizeIncrement);

    pbBaseLocation = pictureBox1.Location;
    pbEnterLocation = pbBaseLocation;
    pbEnterLocation.Offset(pbSizeIncrement / -2, pbSizeIncrement / -2);
}

// use calculated values in your EventHandlers
private void pictureBox1_MouseEnter(object sender, EventArgs e)
{
    pictureBox1.Size = pbEnterSize;
    pictureBox1.Location = pbEnterLocation;
}

private void pictureBox1_MouseLeave(object sender, EventArgs e)
{
    pictureBox1.Size = pbBaseSize;
    pictureBox1.Location = pbBaseLocation;
}

private void pictureBox1_MouseEnter(object sender, EventArgs e)
{
    pictureBox2.Visible = true;
    pictureBox1.Visible = false;
}

private void pictureBox2_MouseLeave(object sender, EventArgs e)
{
    pictureBox1.Visible = true;
    pictureBox2.Visible = false;
}