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我想禁用 ToolStripDropDownButton 下拉菜单上的下拉阴影。如果下拉菜单包含本身具有下拉菜单的项目（例如多级菜单），则在 ToolStripDropDownButton 上将 DropShadowEnabled 设置为 false 会导致顶级下拉菜单出现在错误的位置。见附图。

在此处输入图像描述

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
        toolStripDropDownButton1.DropDown.DropShadowEnabled = false;
    }
}


partial class Form1
{
    /// <summary>
    /// Required designer variable.
    /// </summary>
    private System.ComponentModel.IContainer components = null;

    /// <summary>
    /// Clean up any resources being used.
    /// </summary>
    /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
    protected override void Dispose(bool disposing)
    {
        if (disposing && (components != null))
        {
            components.Dispose();
        }
        base.Dispose(disposing);
    }

    #region Windows Form Designer generated code

    /// <summary>
    /// Required method for Designer support - do not modify
    /// the contents of this method with the code editor.
    /// </summary>
    private void InitializeComponent()
    {
        System.ComponentModel.ComponentResourceManager resources = new System.ComponentModel.ComponentResourceManager(typeof(Form1));
        this.toolStrip1 = new System.Windows.Forms.ToolStrip();
        this.toolStripDropDownButton1 = new System.Windows.Forms.ToolStripDropDownButton();
        this.item1ToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
        this.subitem1ToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
        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(292, 25);
        this.toolStrip1.TabIndex = 0;
        this.toolStrip1.Text = "toolStrip1";
        // 
        // toolStripDropDownButton1
        // 
        this.toolStripDropDownButton1.DisplayStyle = System.Windows.Forms.ToolStripItemDisplayStyle.Image;
        this.toolStripDropDownButton1.DropDownItems.AddRange(new System.Windows.Forms.ToolStripItem[] {
        this.item1ToolStripMenuItem});
        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";
        // 
        // item1ToolStripMenuItem
        // 
        this.item1ToolStripMenuItem.DropDownItems.AddRange(new System.Windows.Forms.ToolStripItem[] {
        this.subitem1ToolStripMenuItem});
        this.item1ToolStripMenuItem.Name = "item1ToolStripMenuItem";
        this.item1ToolStripMenuItem.Size = new System.Drawing.Size(152, 22);
        this.item1ToolStripMenuItem.Text = "item1";
        // 
        // subitem1ToolStripMenuItem
        // 
        this.subitem1ToolStripMenuItem.Name = "subitem1ToolStripMenuItem";
        this.subitem1ToolStripMenuItem.Size = new System.Drawing.Size(152, 22);
        this.subitem1ToolStripMenuItem.Text = "subitem1";
        // 
        // Form1
        // 
        this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
        this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
        this.ClientSize = new System.Drawing.Size(292, 273);
        this.Controls.Add(this.toolStrip1);
        this.Name = "Form1";
        this.Text = "Form1";
        this.toolStrip1.ResumeLayout(false);
        this.toolStrip1.PerformLayout();
        this.ResumeLayout(false);
        this.PerformLayout();

    }

    #endregion

    private System.Windows.Forms.ToolStrip toolStrip1;
    private System.Windows.Forms.ToolStripDropDownButton toolStripDropDownButton1;
    private System.Windows.Forms.ToolStripMenuItem item1ToolStripMenuItem;
    private System.Windows.Forms.ToolStripMenuItem subitem1ToolStripMenuItem;
}
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1 回答 1

1

这是 ToolStripItem 类中非常典型的损失。显然这是一个错误，它可能是在他们应用 hack 解决 Windows 问题时引入的。您仍然可以在参考源中看到内部错误编号：

public bool DropShadowEnabled {
    get {
        // VSWhidbey 338272 - DropShadows are only supported on TopMost windows
        // due to the flakeyness of the way it's implemented in the OS. (Non toplevel
        // windows can have parts of the shadow disappear because another window can get
        // sandwiched between the SysShadow window and the dropdown.)
        return dropShadowEnabled && TopMost && DisplayInformation.IsDropShadowEnabled;
    }
    set {  // etc... }
}

但是在设置器和渲染器中没有相应的修复。

他们提到的脆弱性实际上在 Vista 中得到了修复，您仍然在 XP 上运行，因此您看不到它。投影在 Aero 桌面上的处理方式不同，无论是否启用，它都是系统设置。所以在 Aero 上使用该属性是完全无效的。

这些 ToolStripItem 类错误在 .NET 2.0 发布后没有得到修复，因为整个 Winforms 团队都转移到了 WPF 组。而且它们现在肯定没有得到修复，尽管您可以自由地在 connect.microsoft.com 上提交错误，但没有意义。

由于该属性现在是系统设置，因此该属性不再对更高版本的 Windows 产生影响，因此唯一合乎逻辑的事情就是认输。不要更改属性。

于 2012-12-15T14:22:19.293 回答