MDI窗体工具栏(ToolStrip)合并

public interface IToolStrip
{
    ToolStrip OwnToolStrip
    {
        get;
    }
}

public partial class Form2 : Form, IToolStrip
{
    public Form2()
    {
        InitializeComponent();
        
    }

    public ToolStrip OwnToolStrip
    {
        get
        {
            //toolStrip1为子窗体工具栏
            return toolStrip1;
        }
    }
}

private void Form1_MdiChildActivate(object sender, EventArgs e)
{
    //toolStrip1为父窗体工具栏
    ToolStripManager.RevertMerge(toolStrip1);
    if (this.ActiveMdiChild != null)
    {
        if ((ActiveMdiChild as IToolStrip).OwnToolStrip != null)
        {
            ToolStripManager.Merge((ActiveMdiChild as IToolStrip).OwnToolStrip, toolStrip1);
        }
    }
    //若工具栏没有工具项时,隐藏该工具栏
    if (toolStrip1.Items.Count > 0)
        toolStrip1.Visible = true;
    else
        toolStrip1.Visible = false;
}