C#实现鼠标拖拽无边框浮动窗体的方法

[dllimport("user32.dll")]
public static extern bool releasecapture();

[dllimport("user32.dll")]
public static extern bool sendmessage(intptr hwdn,int wmsg,int mparam,int lparam);

//------------------------------------------------------------------------------
// <auto-generated>
//     此代码由工具生成。
//     运行时版本:4.0.30319.42000
//
//     对此文件的更改可能会导致不正确的行为，并且如果
//     重新生成代码，这些更改将会丢失。
// </auto-generated>
//------------------------------------------------------------------------------
 
namespace _198.properties {
    using system;
    
    
    /// <summary>
    ///   一个强类型的资源类，用于查找本地化的字符串等。
    /// </summary>
    // 此类是由 stronglytypedresourcebuilder
    // 类通过类似于 resgen 或 visual studio 的工具自动生成的。
    // 若要添加或移除成员，请编辑 .resx 文件，然后重新运行 resgen
    // (以 /str 作为命令选项)，或重新生成 vs 项目。
    [global::system.codedom.compiler.generatedcodeattribute("system.resources.tools.stronglytypedresourcebuilder", "17.0.0.0")]
    [global::system.diagnostics.debuggernonusercodeattribute()]
    [global::system.runtime.compilerservices.compilergeneratedattribute()]
    internal class resources {
        
        private static global::system.resources.resourcemanager resourceman;
        
        private static global::system.globalization.cultureinfo resourceculture;
        
        [global::system.diagnostics.codeanalysis.suppressmessageattribute("microsoft.performance", "ca1811:avoiduncalledprivatecode")]
        internal resources() {
        }
        
        /// <summary>
        ///   返回此类使用的缓存的 resourcemanager 实例。
        /// </summary>
        [global::system.componentmodel.editorbrowsableattribute(global::system.componentmodel.editorbrowsablestate.advanced)]
        internal static global::system.resources.resourcemanager resourcemanager {
            get {
                if (object.referenceequals(resourceman, null)) {
                    global::system.resources.resourcemanager temp = new global::system.resources.resourcemanager("_198.properties.resources", typeof(resources).assembly);
                    resourceman = temp;
                }
                return resourceman;
            }
        }
        
        /// <summary>
        ///   重写当前线程的 currentuiculture 属性，对
        ///   使用此强类型资源类的所有资源查找执行重写。
        /// </summary>
        [global::system.componentmodel.editorbrowsableattribute(global::system.componentmodel.editorbrowsablestate.advanced)]
        internal static global::system.globalization.cultureinfo culture {
            get {
                return resourceculture;
            }
            set {
                resourceculture = value;
            }
        }
        
        /// <summary>
        ///   查找 system.drawing.bitmap 类型的本地化资源。
        /// </summary>
        internal static system.drawing.bitmap _04 {
            get {
                object obj = resourcemanager.getobject("_04", resourceculture);
                return ((system.drawing.bitmap)(obj));
            }
        }
    }
}

namespace _198
{
    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()
        {
            suspendlayout();
            // 
            // form1
            // 
            autoscaledimensions = new sizef(7f, 17f);
            autoscalemode = autoscalemode.font;
            backgroundimage = properties.resources._04;
            backgroundimagelayout = imagelayout.stretch;
            clientsize = new size(311, 218);
            formborderstyle = formborderstyle.none;
            name = "form1";
            text = "form1";
            mousedown += form1_mousedown;
            resumelayout(false);
        }
 
        #endregion
    }
}

// 拖拽无边框浮动窗体
using system.runtime.interopservices;
namespace _198
{
    public partial class form1 : form
    {
        #region 本程序中用到的api函数
        [dllimport("user32.dll")]
        public static extern bool releasecapture();//用来释放被当前线程中某个窗口捕获的光标
        [dllimport("user32.dll")]
        public static extern bool sendmessage(intptr hwdn, int wmsg, int mparam, int lparam);//向指定的窗体发送windows消息
        #endregion
 
        #region 本程序中需要声明的变量
        public const int wm_syscommand = 0x0112;    //该变量表示将向windows发送的消息类型
        public const int sc_move = 0xf010;          //该变量表示发送消息的附加消息
        public const int htcaption = 0x0002;        //该变量表示发送消息的附加消息
        #endregion
 
        public form1()
        {
            initializecomponent();
        }
        /// <summary>
        /// 鼠标落在窗体上，随意拖拽
        /// </summary>
        private void form1_mousedown(object sender, mouseeventargs e)
        {
            releasecapture();                                                                                       //用来释放被当前线程中某个窗口捕获的光标
            sendmessage(handle, wm_syscommand, sc_move + htcaption, 0); //向windows发送拖动窗体的消息
        }
    }
}