mdichild表单不显示

Question

我已经设计了一堆mdichild表单，并希望将这些表单显示为mdichild。我将主表单设置为mdi，并且能够正确地将其中一个表单显示为mdichild。给我惹麻烦的代码是：

    public partial class KeyboardSettingsForm : Form
    {
        private mainForm _mForm;

        public KeyboardSettingsForm()
        {
            InitializeComponent();
            _mForm = new mainForm(); //<---mdiparent
            this.MdiParent = _mForm; //<---Commenting out this line shows the form

            this.Shown += new System.EventHandler(this.KeyboardSettingsForm_Shown);

        }
    }

我不知道为什么，如果我评论掉：this.MdiParent = _mForm;表单将显示(但不是作为一个mdichild)。如果代码完好无损，表单就会拒绝显示。我怎么才能把那张表格显示成一个小东西呢？

更新的工作代码

public partial class mainForm : Form
{
    private NavigationForm _navForm;
    public mainForm()
    {
        InitializeComponent();


        this.Shown += new System.EventHandler(this.mainForm_Shown);

    }

    private void mainForm_Shown(object sender, EventArgs e)
    {
        _navForm = new NavigationForm(this);
        _navForm.MdiParent = this;
        _navForm.Show();
    }

    private void mainForm_Load(object sender, EventArgs e)
    {

    }

}

public partial class NavigationForm : Form
{

    private KeyboardSettingsForm _wKeyboard;

    public NavigationForm(Form frm)
    {
        InitializeComponent();

        _wKeyboard = new KeyboardSettingsForm(frm);


    }

    private void NavigationForm_Load(object sender, EventArgs e)
    {

    }

    private void keyboardPictureBox_Click(object sender, EventArgs e)
    {
        _wKeyboard.Show();

    }

}

public partial class KeyboardSettingsForm : Form
{
    private Form _mdiParent;

    public KeyboardSettingsForm(Form frm)
    {
        InitializeComponent();
        _mdiParent = frm;
        this.MdiParent = frm;

        this.Shown += new System.EventHandler(this.KeyboardSettingsForm_Shown);

    }

    private void KeyboardSettingsForm_Load(object sender, EventArgs e)
    {
        MessageBox.Show(_mdiParent.Name);
    }

    private void KeyboardSettingsForm_Shown(object sender, EventArgs e)
    {

    }
}

Answer 1

您需要使mForm成为mdi容器：

mForm.IsMdiContainer = true;

Answer 2

您需要显式地显示主表单如下：

_mForm = new mainForm();
this.MdiParent = _mForm;

this.Shown += this.KeyboardSettingsForm_Shown;

_mForm.Show(); // show mdi-parent explicitly because only the application's start-up form shows automatically.

Answer 3

你是说谁是KeyboardSettingsForm的父母，但你在向父母展示什么？

_mForm = new mainForm(); //<---mdiparent not shown :(
this.MdiParent = _mForm;

尝尝这个

_mForm = new mainForm();
_mForm.Show();//show your parent first
this.MdiParent = _mForm;

但是即使在上面的代码也没有什么意义。你是故意这样做的吗？

public partial class KeyboardSettingsForm : Form
{
    private mainForm _mForm;

    public KeyboardSettingsForm(mainForm mForm)
    {
        InitializeComponent();
        this._mForm = mForm;//Did you mean this?
        this.MdiParent = _mForm;

        this.Shown += new System.EventHandler(this.KeyboardSettingsForm_Shown);

    }
}