DockPanel 子窗体如何在父窗体打开另一子窗体，以选项卡式存在

父窗体代码：

//dockPanel1为DockPanel的实例
FrmOption frmOption = new FrmOption(dockPanel1);
frmOption.Show(dockPanel1);

子窗体代码:

public partial class FrmOption : DockContent
{
private readonly DockPanel dockPanel1 = new DockPanel();

public FrmOption(DockPanel dockPanel1)
{
InitializeComponent();
this.dockPanel1 = dockPanel1;
}

private void FrmOption_Load(object sender, EventArgs e)
{
//调用父窗体的ToolStripProgressBar ,在父窗体ToolStripProgressBar

必须设置为Modifier=Internal以上级别
ToolStripProgressBar toolStripProgressBar = ((MainForm)MdiParent).toolStripProgressBar;
toolStripProgressBar.Visible = true;
toolStripProgressBar.Value = 90;
}

private void button1_Click(object sender, EventArgs e)
{
MainForm mainForm = MdiParent as MainForm;
foreach (Form child in mainForm.MdiChildren)
{
//此处将在父窗体选项卡上显示
if (child.Name == "FrmDepartment")
{
child.Activate();
return;
}
}
FrmDepartment frm = new FrmDepartment();
frm.Show(dockPanel1);
}
}

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