c#怎么样让窗口没有标题栏，但是有周围边框
this.FormBorderStyle = FormBorderStyle.None;这样连边框也没有

namespace WindowsFormsApplication1
{
    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()
        {
            this.button1 = new System.Windows.Forms.Button();
            this.checkBox1 = new System.Windows.Forms.CheckBox();
            this.listBox1 = new System.Windows.Forms.ListBox();
            this.groupBox1 = new System.Windows.Forms.GroupBox();
            this.label1 = new System.Windows.Forms.Label();
            this.SuspendLayout();
            // 
            // button1
            // 
            this.button1.Location = new System.Drawing.Point(62, 77);
            this.button1.Name = "button1";
            this.button1.Size = new System.Drawing.Size(79, 32);
            this.button1.TabIndex = 0;
            this.button1.Text = "button1";
            this.button1.UseVisualStyleBackColor = true;
            // 
            // checkBox1
            // 
            this.checkBox1.AutoSize = true;
            this.checkBox1.Location = new System.Drawing.Point(45, 162);
            this.checkBox1.Name = "checkBox1";
            this.checkBox1.Size = new System.Drawing.Size(80, 17); 
 
            this.checkBox1.TabIndex = 1;
            this.checkBox1.Text = "checkBox1";
            this.checkBox1.UseVisualStyleBackColor = true;
            // 
            // listBox1
            // 
            this.listBox1.FormattingEnabled = true;
            this.listBox1.Location = new System.Drawing.Point(165, 137);
            this.listBox1.Name = "listBox1";
            this.listBox1.Size = new System.Drawing.Size(57, 69);
            this.listBox1.TabIndex = 2;
            // 
            // groupBox1
            // 
            this.groupBox1.Location = new System.Drawing.Point(163, 38);
            this.groupBox1.Name = "groupBox1";
            this.groupBox1.Size = new System.Drawing.Size(95, 54);
            this.groupBox1.TabIndex = 3;
            this.groupBox1.TabStop = false;
            this.groupBox1.Text = "groupBox1";
            // 
            // label1
            // 
            this.label1.AutoSize = true;
            this.label1.Location = new System.Drawing.Point(59, 38);
            this.label1.Name = "label1";
            this.label1.Size = new System.Drawing.Size(35, 13); 
 
            this.label1.TabIndex = 4;
            this.label1.Text = "label1";
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(284, 261);
            this.ControlBox = false;
            this.Controls.Add(this.label1);
            this.Controls.Add(this.groupBox1);
            this.Controls.Add(this.listBox1);
            this.Controls.Add(this.checkBox1);
            this.Controls.Add(this.button1);
            this.MaximizeBox = false;
            this.MinimizeBox = false;
            this.Name = "Form1";
            this.ShowInTaskbar = false;
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private System.Windows.Forms.Button button1;
        private System.Windows.Forms.CheckBox checkBox1;
        private System.Windows.Forms.ListBox listBox1;
        private System.Windows.Forms.GroupBox groupBox1;
        private System.Windows.Forms.Label label1;
    }
}

两步操作：
1、将form的ControlBox属性置为false。
2、将form的Text属性置为""。