粘性Snap-to-Center控制

介绍本文展示了如何在MouseEnter上将鼠标指针拖动到控件的中心并保持一段时间。在分配的时间(默认是1/4秒)之后，控件释放它对光标的控制。这个方法适用于任何控件-下面的例子有一个按钮和一个PictureBox: 背景我创建了一个工具，它的窗口可以调整为一个非常小的界面，以避免妨碍(如WinAmp -一个没有标题的小工具条)。这些按钮在最小尺寸时，很难按。我需要一种方法来引导用户到按钮的中心，这样他们就不会意外地点击邻接的按钮。当这个:扩展到这个:时，很难将鼠标移到按钮上。通过实现这些事件，用户可以轻松地将鼠标放置在控件上，即使它太小而无法精确地单击。粘着按钮的感觉也会很快结束，所以它不会成为用户的烦恼。使用的代码要使控件具有粘性，您需要将其鼠标事件MouseEnter和MouseMove设置为StartSnap和CheckSnap事件处理程序。 c# 隐藏,收缩,复制Code

public partial class Form1 : Form
{
    // When the Snap Hold should break
    private DateTime dtSnapEnd;
    // Duration of the Snap Hold - set this value to 
    // determine how long we hold the cursor
    private double dReleaseTime = 250;

    private void SnapToCenter(Control control)
    {
        Point pCenter = control.PointToScreen(new Point(0, 0));
        // get the center of the control
        pCenter.X += control.Width / 2;
        pCenter.Y += control.Height / 2;
        // set the cursor position to the center
        Cursor.Position = pCenter;
    }

    // Event to handle MouseEnter events
    private void StartSnap(object sender, EventArgs e)
    {
        // start by centering the mouse
        SnapToCenter((Control)sender);
        // set the time when the snap should break
        dtSnapEnd = DateTime.Now.AddMilliseconds(dReleaseTime);
    }

    // Event to handle MouseMove events
    private void CheckSnap(object sender, MouseEventArgs e)
    {
        // if we have not passed the Snap End time,
        // then center the mouse
        if (DateTime.Now < dtSnapEnd)
        {
            SnapToCenter((Control)sender);
        }
    }

    //... 
}

在设计视图: 在窗体中添加控件。在控件属性上，切换到事件，并将MouseEnter事件设置为StartSnap。将MouseMove事件设置为CheckSnap。 VB.NET 在Visual Basic中，我们需要用不同的方式处理事件，因为VB。NET不使用通用事件处理程序(至少从设计接口): 创建窗体并向其添加控件。在表单的Form_Load事件中，为每个控件添加以下内容: 隐藏,复制Code

AddHandler Button1.MouseEnter, AddressOf StartSnap
AddHandler Button1.MouseMove, AddressOf CheckSnap

AddHandler YourControlHere.MouseEnter, AddressOf StartSnap
AddHandler YourControlHere.MouseMove, AddressOf CheckSnap

这里是完整的VB代码来处理事件: 隐藏,收缩,复制Code

Public Class Form1

    ' When the Snap Hold should break
    Private dSnapEnd As Date
    ' Duration of the Snap Hold - set this value to 
    ' determine how long we hold the cursor
    Private dReleaseTime As Double = 250

    Private Sub SnapToCenter(ByVal control As Control)
        Dim pCenter As Point
        ' get the center of the control
        pCenter.X = control.Width / 2
        pCenter.Y = control.Height / 2
        ' Set the cursor to the center
        Cursor.Position = control.PointToScreen(pCenter)
    End Sub

    ' Event to handle MouseEnter events
    Private Sub StartSnap(ByVal sender As System.Object, _
                          ByVal e As System.EventArgs)
        ' Start by snapping the cursor to the center
        SnapToCenter(CType(sender, Control))

        ' Set the starting and ending snap times
        dSnapEnd = dSnapStart.AddMilliseconds(dReleaseTime)
    End Sub

    ' Event to handle MouseMove events
    Private Sub CheckSnap(ByVal sender As System.Object, _
    ByVal e As System.Windows.Forms.MouseEventArgs)
        ' If we've not reached the SnapEnd time, center the mouse
        If Date.Now < dSnapEnd Then
            SnapToCenter(CType(sender, Control))
        End If
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles MyBase.Load
        ' Add the event handlers for each control.
        AddHandler Button1.MouseEnter, AddressOf StartSnap
        AddHandler Button1.MouseMove, AddressOf CheckSnap

        AddHandler YourControlHere.MouseEnter, AddressOf StartSnap
        AddHandler YourControlHere.MouseMove, AddressOf CheckSnap
    End Sub

End Class

确认感谢Karl Moore为控件上的光标定心代码。历史 2008.09.17 -初始文章与示例应用程序。本文转载于：http://www.diyabc.com/frontweb/news507.html