动态用户控件事件不执行 C# 中的方法

Question

我正在努力弄清楚为什么我的用户控件事件没有执行。我在动态用户控件 "MainControl" 中有一个动态用户控件 "MainMenu"。

在 MainMenu 中我有以下内容：

public partial class MainMenu : UserControl
{
    public MainMenu()
    {
        InitializeComponent();

        ///
        ///Event Subscriptions
        /// 
        this.LostFocus += this.MainMenu_LostFocus;
    }

    public void MainMenu_LostFocus(object sender, EventArgs e)
    {
        this.Visible = false;
    }
}

在主控件中：

public partial class MainControl : UserControl
{
    private Custom_UI.MainMenu mainMenu = new Custom_UI.MainMenu();
    public MainControl()
    {
        InitializeComponent();
        mainMenu.Visible = false;
        mainMenu.BringToFront();            
        this.Controls.Add(mainMenu);
        mainMenu.BringToFront();
    }
    private void menuButton1_Click(object sender, EventArgs e)
    {
        if (mainMenu.Visible)
        {
            mainMenu.Visible = false;                
        }
        else
        {
            mainMenu.Visible = true;
            this.Focus();
        }
    }
}

最后是主窗体：

public partial class Form1 : Form
{
    MainControl mainControl = new MainControl() {
        Dock = DockStyle.Fill
    };
    public Form1()
    {
        InitializeComponent();
        this.Controls.Add(mainControl);
    }
}

所以基本上，当我单击表单上的其他地方时，方法 MainMenu_LostFocus 不会被调用。我也尝试过使用 this.MouseLeave 而不是 this.LostFocus。

希望我已经足够清楚了，在此先感谢。

Answer 1

使用 focus/focus 丢失等总是很棘手。我的建议是稍微修改一下您的代码。

首先你的 MainMenu 需要集中注意力才能失去它

其次要失去它，另一个控件需要获得焦点 - 这需要由您处理（仅单击 MainControl 不起作用，您需要强制执行）

试试这个：

public partial class MainControl : UserControl
{
    private Custom_UI.MainMenu mainMenu = new Custom_UI.MainMenu();
    public MainControl()
    {
        InitializeComponent();
        mainMenu.Visible = false;
        mainMenu.BringToFront();            
        this.Controls.Add(mainMenu);
        mainMenu.BringToFront();
        this.Click += me_Click;
    }

    private void me_Click(object sender, EventArgs e)
    {
        this.Focus(); //this will cause main control to get control (if main menu is focused it'll lose focus and handle it's focus lost and set visible to false in result
    }

    private void menuButton1_Click(object sender, EventArgs e)
    {
        if (mainMenu.Visible)
        {
            mainMenu.Visible = false;   // this should work anyway
        }
        else
        {
            mainMenu.Visible = true;
            mainMenu.Focus(); //when showing mainMenu set focus to it
        }
    }
}

Answer 2

好的...以免尝试另一种改进的方法。原因是我们不想被迫处理对每个添加到 MainControl 的控件的点击并强制它获得焦点。就是笨拙。

我们还想将整个代码封装在一个控件中 (MainMenu) - 不是 "must have"，但肯定是 "nice to have"

这是我的新想法：

 public partial class MainMenu : UserControl
    {

        //this class will be checking native windows messages, the one we're interested in is "MouseDown" with 0x0201 code 
        //(i won't be describing the whole stuff what is going inside: have that checked if you wish in documentation :)

        [SecurityPermission(SecurityAction.LinkDemand, Flags = SecurityPermissionFlag.UnmanagedCode)]
        public class TestMessageFilter : IMessageFilter
        {
            const int WM_MOUSEMOVE = 0x200;
            const int WM_LBUTTONDOWN = 0x0201;

            public event EventHandler MouseMoved;
            public event EventHandler MouseDown;

            public bool PreFilterMessage(ref Message m)
            {
                // Blocks all the messages relating to the left mouse button.
                if (m.Msg == WM_LBUTTONDOWN)
                {
                    MouseDown?.Invoke(this, new EventArgs());
                }
                return false;
            }
        }


        public MainMenu()
        {
            InitializeComponent();

            //use our class that checks Windows Messages, subscribe it's event
            var tmf = new TestMessageFilter();
            tmf.MouseDown += UserControl1_MouseDown;
            //and add our class to Application's messages filter.
            Application.AddMessageFilter(tmf);

            //use "ordinary" events to detect mouse enter/mouse leave over control
            this.MouseLeave += UserControl1_MouseLeave;
            this.MouseEnter += UserControl1_MouseEnter;
        }

        private void UserControl1_MouseDown(object sender, EventArgs e)
        {
            //if mouse is not over control make it's visible false
            if (mouseLeft)
            {
                this.Visible = false;
            }
        }

        //variable to save mouse state (if that is over the control, or left)
        private bool mouseLeft;

        private void UserControl1_MouseEnter(object sender, EventArgs e)
        {
            mouseLeft = false;
        }


        private void UserControl1_MouseLeave(object sender, EventArgs e)
        {
            mouseLeft = true;
        }

    }

希望这个解决方案会更好，更有用

动态用户控件事件不执行 C# 中的方法

Dynamic User Control events not executing methods in C#

c#

events

user-controls

dynamic-usercontrols