Question

我需要一个.NET Framework标准事件中不存在的事件。例如，鼠标左键移动时鼠标移动。

我还需要改变一些行为。例如，我有一些按钮，我想在鼠标左键按下时更改光标所在的每个按钮的背景图像，但是当我单击一个按钮并按住鼠标左键时，我移动鼠标时其他按钮不会引发任何事件。

我该怎么办？如何创建新活动？我该如何改变行为？

感谢任何帮助。

Answer 1

你的问题是当一个按钮上发生MouseDown事件时，该按钮“捕获”鼠标并且在释放按钮之前不会释放它，这意味着其他按钮不会接收到MouseMove事件。 / p>

有一些代码from here可能有所帮助：

 // Assuming all buttons subscribe to this event:
 private void buttons_MouseMove (object sender, MouseEventArgs e)
 {
   if (e.Button == System.Windows.Forms.MouseButtons.Left)
      {
       Control control = (Control) sender;
       if (control.Capture)
       {
          control.Capture = false;
       }
       if (control.ClientRectangle.Contains (e.Location)) 
       {
           Control.BackgroundImage = ...;
       }
    }
  }

Answer 2

MouseMove-Event有一个名为'Button'的属性，告诉你按下了哪个按钮。所以你要做的就是这样：

void panel1_MouseMove(Object sender, System::Windows::Forms::MouseEventArgs e) {

    if(e.Button = MouseButtons.Left){
        //Do what you want when mouse_move with left button pressed      
    }      
}

以上代码未经过测试，我没有查找属性的正确拼写等，只需在IntelliSense / MSDN中尝试一下。

您可以在MSDN中找到更多信息： http://msdn.microsoft.com/en-us/library/system.windows.forms.control.mousemove%28v=vs.71%29.aspx

对于第二个问题，只需尝试找到拟合事件或覆盖WindowProc-Event-Function，您就可以收听WindowMessages并获取所需内容 - 更多信息在http://msdn.microsoft.com/en-us/library/ms633573%28v=VS.85%29.aspx和{{3}上给出}}

Answer 3

本示例（一个包含 2 个文本框的表单）通过在一个文本框上单击左键并在另一个文本框上释放鼠标，将文本框中的文本移动到另一个文本框。如果您注释掉捕获部分，它将停止工作。

Public Class Form1
Dim MousebuttonIsPressed As Boolean = False
Dim TextboxWhereMouseDown As TextBox
Dim TextboxWhereMouseUp As TextBox
Private Sub Form1_mouseup(sender As Object, e As EventArgs) Handles MyBase.MouseUp
    MousebuttonIsPressed = False
End Sub
Private Sub Textbox_MouseDown(sender As TextBox, e As MouseEventArgs) Handles TextboxOne.MouseDown, TextboxTwo.MouseDown ' etc for each textbox involved
    TextboxWhereMouseDown = sender
    If e.Button = MouseButtons.Left Then
        MousebuttonIsPressed = True
    End If
End Sub
Private Sub Textbox_MouseUp(sender As TextBox, e As MouseEventArgs) Handles TextboxOne.MouseUp, TextboxTwo.MouseUp ' etc.
    TextboxWhereMouseUp = sender
    If Not (TextboxWhereMouseDown Is TextboxWhereMouseUp) Then
        TextboxWhereMouseUp.Text = TextboxWhereMouseDown.Text
        TextboxWhereMouseDown.Text = ""
    End If
    MousebuttonIsPressed = False
End Sub
Private Sub Textbox_MouseEnter(sender As TextBox, e As EventArgs) Handles TextboxOne.MouseEnter, TextboxTwo.MouseEnter ' etc
    If MousebuttonIsPressed Then
        TextboxWhereMouseUp = sender
    End If
End Sub
Private Sub Textbox_MouseMove(sender As TextBox, e As MouseEventArgs) Handles TextboxOne.MouseMove, TextboxTwo.MouseMove ' etc
    If (e.Button = System.Windows.Forms.MouseButtons.Left) Then
        Dim Contrl As Control = sender
        If Contrl.Capture Then
            If Not Contrl.ClientRectangle.Contains(e.Location) Then ' to allow selection of text
                Contrl.Capture = False
            End If
        End If
    End If
End Sub
End Class

按下按钮时移动鼠标时会引发什么事件？

3 个答案: