Form.Deactivate中鼠标按钮状态错误

Question

当我检查Form.Deactivate中的鼠标按钮状态时，它不表示必须导致停用Form的状态。

就给定的示例项目而言，这意味着，如果通过按下按钮刚刚显示了dropDownForm（并因此获得了焦点），并且我在dropDownForm的边界矩形外部按住了鼠标左键，则正确触发了Deactivate事件，但是在其处理程序体内，鼠标状态错误地显示为MouseButtons.None。

有趣的是，唯一的例外是当我单击MainForm的标题栏时，两次触发了停用，第一次出现是显示正确的鼠标按钮状态。

在Deactivate事件中是否有任何方法可以使鼠标按钮状态得到正确的结果？

using System;
using System.Drawing;
using System.Windows.Forms;

namespace FormDeactivateTest
{
    public class MainForm : Form
    {
        Form dropDownForm;
        Button button1;

        public MainForm()
        {
            button1 = new Button();
            SuspendLayout();

            button1.Location = new Point(107, 54);
            button1.Name = "button1";
            button1.Size = new Size(75, 23);
            button1.TabIndex = 0;
            button1.Text = "Show Form";
            button1.UseVisualStyleBackColor = true;
            button1.Click += Button1Click;

            dropDownForm = new Form();
            dropDownForm.FormBorderStyle = FormBorderStyle.FixedToolWindow;
            dropDownForm.ControlBox = false;
            dropDownForm.ShowInTaskbar = false;
            dropDownForm.ShowIcon = false;
            dropDownForm.MinimizeBox = false;
            dropDownForm.MaximizeBox = false;
            dropDownForm.HelpButton = false;
            dropDownForm.Text = "";
            dropDownForm.TopMost = true;
            dropDownForm.StartPosition = FormStartPosition.Manual;
            dropDownForm.Deactivate += dropDownDeactivate;

            AutoScaleDimensions = new SizeF(6F, 13F);
            AutoScaleMode = AutoScaleMode.Font;
            ClientSize = new Size(284, 261);
            Controls.Add(button1);
            Name = "MainForm";
            Text = "FormDeactivateTest";
            ResumeLayout(false);
        }

        void Button1Click(object sender, EventArgs e)
        {
            if (dropDownForm.Visible) dropDownForm.Hide();
            else
            {
                dropDownForm.Location = button1.PointToScreen(new Point(0, button1.Height+1)); 
                dropDownForm.Show();
            }
        }

        void dropDownDeactivate(object sender, EventArgs e)
        {
            if (Control.MouseButtons == MouseButtons.None)
            {
                MessageBox.Show("Mouse button press not recognized");
            }
            else
            {
                MessageBox.Show("Mouse button pressed");
            }
        }
    }
}

Answer 1

更新如果您要使用的是一个包含任意内容的下拉面板，则可以使用ToolStripDropDownButton和ToolStripControlHost。优势包括：

• 它自行关闭
• 随表格一起移动
• 它看起来更符合Windows标准设计
• 它支持键盘导航（Tab，Down等）
• 您必须编写更少的代码！

如果您希望它不出现在顶部，您甚至可以取消停放它或将其放在另一个面板中。

public class MainForm : Form
{
    private ToolStrip toolStrip1;
    private ToolStripDropDownButton toolStripDropDownButton1;

    public MainForm()
    {
        System.ComponentModel.ComponentResourceManager resources = new System.ComponentModel.ComponentResourceManager(typeof(MainForm));
        this.toolStrip1 = new System.Windows.Forms.ToolStrip();
        this.toolStripDropDownButton1 = new System.Windows.Forms.ToolStripDropDownButton();
        this.toolStrip1.SuspendLayout();
        this.SuspendLayout();
        // 
        // toolStrip1
        // 
        this.toolStrip1.Items.AddRange(new System.Windows.Forms.ToolStripItem[] {
            this.toolStripDropDownButton1});
        this.toolStrip1.Location = new System.Drawing.Point(0, 0);
        this.toolStrip1.Name = "toolStrip1";
        this.toolStrip1.Size = new System.Drawing.Size(284, 25);
        this.toolStrip1.TabIndex = 0;
        this.toolStrip1.Text = "toolStrip1";
        // 
        // toolStripDropDownButton1
        // 
        this.toolStripDropDownButton1.DisplayStyle = System.Windows.Forms.ToolStripItemDisplayStyle.Image;
        this.toolStripDropDownButton1.Image = ((System.Drawing.Image)(resources.GetObject("toolStripDropDownButton1.Image")));
        this.toolStripDropDownButton1.ImageTransparentColor = System.Drawing.Color.Magenta;
        this.toolStripDropDownButton1.Name = "toolStripDropDownButton1";
        this.toolStripDropDownButton1.Size = new System.Drawing.Size(29, 22);
        this.toolStripDropDownButton1.Text = "toolStripDropDownButton1";
        // 
        // MainForm
        // 
        this.ClientSize = new System.Drawing.Size(284, 261);
        this.Controls.Add(this.toolStrip1);
        this.Name = "MainForm";
        this.toolStrip1.ResumeLayout(false);
        this.toolStrip1.PerformLayout();
        this.ResumeLayout(false);
        this.PerformLayout();

        var tv = new TreeView();
        tv.Nodes.Add("test", "testText");
        tv.Nodes.Add("test2", "testTexttt");
        tv.Nodes.Add("test2", "testTexttttttt");
        var hosted = new ToolStripControlHost(tv);
        toolStripDropDownButton1.DropDownItems.Add(hosted);

    }
}

上一个答案

用户也可以通过Alt + Tab触发Deactivate，远离您的表单（这将导致没有鼠标单击），因此不确定您为什么要这样做。

但是您可以在OnMouseUp上使用一个标志和一个侦听器来实现。如果您单击父母的边框，则不会触发。

private bool recentlyDeactivated = false;
protected override void OnMouseUp(MouseEventArgs e)
{
    base.OnMouseUp(e);

    if (recentlyDeactivated)
    {
        if (e.Button == MouseButtons.None)
        {
            MessageBox.Show("Mouse button press not recognized");
        }
        else
        {
            MessageBox.Show("Mouse button pressed");
        }
    }

    recentlyDeactivated = false;
}

void dropDownDeactivate(object sender, EventArgs e)
{
    recentlyDeactivated = true;
}