introduce
Generally speaking, holding down the left mouse button in the title bar can achieve the drag operation.
When a floating form is used, if the form border is included, the interface will give the user a feeling that the user will be unfriendly, so the floating form has no borders. However, for such a form without borders, how to drag and drop?
It is mainly used to implement two API functions of Windows, namely ReleaseCapture and SendMessage:
(1)ReleaseCapture function
This function is used to release the cursor captured by a window in the current thread. The syntax format is as follows:
[DllImport("")]
public static extern bool ReleaseCapture();(2)SendMessage function
This function is used to send Windows messages to the specified form. The syntax format is as follows:
[DllImport("")]
public static extern bool SendMessage(IntPtr hwdn,int wMsg,int mParam,int lParam);(3) Example
In this example, the mouse drops on the form. Before UP, drag and drop the form to any position.
//------------------------------------------------------------------------------
// <auto-generated>
// This code is generated by the tool.// Runtime version: 4.0.30319.42000//
// Changes to this file may cause incorrect behavior and if// Regenerate the code and these changes will be lost.// </auto-generated>
//------------------------------------------------------------------------------
namespace _198.Properties {
using System;
/// <summary>
/// A strongly typed resource class used to find localized strings, etc. /// </summary>
// This class is by StronglyTypedResourceBuilder // The class is automatically generated through a tool similar to ResGen or Visual Studio. // To add or remove members, edit the .ResX file and rerun ResGen // (use /str as command option), or regenerate the VS project. [global::("", "17.0.0.0")]
[global::()]
[global::()]
internal class Resources {
private static global:: resourceMan;
private static global:: resourceCulture;
[global::("", "CA1811:AvoidUncalledPrivateCode")]
internal Resources() {
}
/// <summary>
/// Returns the cached ResourceManager instance used by this class. /// </summary>
[global::(global::)]
internal static global:: ResourceManager {
get {
if ((resourceMan, null)) {
global:: temp = new global::("_198.", typeof(Resources).Assembly);
resourceMan = temp;
}
return resourceMan;
}
}
/// <summary>
/// Rewrite the CurrentUICulture property of the current thread, for /// Perform rewrite using all resource lookups for this strongly typed resource class. /// </summary>
[global::(global::)]
internal static global:: Culture {
get {
return resourceCulture;
}
set {
resourceCulture = value;
}
}
/// <summary>
/// Find a localized resource of type. /// </summary>
internal static _04 {
get {
object obj = ("_04", resourceCulture);
return (()(obj));
}
}
}
}2.
namespace _198
{
partial class Form1
{
/// <summary>
/// Required designer variable.
/// </summary>
private 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))
{
();
}
(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 = ;
BackgroundImage = ._04;
BackgroundImageLayout = ;
ClientSize = new Size(311, 218);
FormBorderStyle = ;
Name = "Form1";
Text = "Form1";
MouseDown += Form1_MouseDown;
ResumeLayout(false);
}
#endregion
}
}3.
In the example, the API function [DllImport("")] used will prompt the error message of CA1401 and SYSLIB1054, ignore it, otherwise the generated form cannot be dragged and dropped. Logically speaking, after following the prompts, P/INVOKE should work normally, but I am not in the mood to debug it. Interested netizens can study it in depth and overcome it. There will be results for them. Please reply. The framework I use is .NET 8.0.
// Drag and drop the frameless floating formusing ;
namespace _198
{
public partial class Form1 : Form
{
#region API functions used in this program [DllImport("")]
public static extern bool ReleaseCapture();// Used to release the cursor captured by a window in the current thread [DllImport("")]
public static extern bool SendMessage(IntPtr hwdn, int wMsg, int mParam, int lParam);//Send Windows messages to the specified form #endregion
#region Variables that need to be declared in this program public const int WM_SYSCOMMAND = 0x0112; //This variable indicates the type of message to be sent to Windows public const int SC_MOVE = 0xF010; //This variable represents the additional message to send the message public const int HTCAPTION = 0x0002; //This variable represents the additional message to send the message #endregion
public Form1()
{
InitializeComponent();
}
/// <summary>
/// The mouse falls on the form and drags it at will /// </summary>
private void Form1_MouseDown(object sender, MouseEventArgs e)
{
ReleaseCapture(); // Used to release the cursor captured by a window in the current thread SendMessage(Handle, WM_SYSCOMMAND, SC_MOVE + HTCAPTION, 0); //Send a message to Windows to drag the form }
}
}The above is the detailed content of C#’s method of dragging and dropping a frameless floating form with a mouse. For more information about C#’s frameless floating form, please pay attention to my other related articles!