Control.OnClick(EventArgs) 方法

定义

命名空间:

System.Windows.Forms

程序集:

System.Windows.Forms.dll

引发 Click 事件。

protected:
 virtual void OnClick(EventArgs ^ e);

protected virtual void OnClick (EventArgs e);

abstract member OnClick : EventArgs -> unit
override this.OnClick : EventArgs -> unit

Protected Overridable Sub OnClick (e As EventArgs)

参数

e

EventArgs

包含事件数据的 EventArgs。

示例

下面的代码示例演示如何在派生类中重写 OnClick 方法。 若要运行该示例，请将以下代码粘贴到同一文件中的窗体类后面。 向窗体添加类型 SingleClickTextBox 为的文本框。

// This is a custom TextBox control that overrides the OnClick method
// to allow one-click selection of the text in the text box.
public ref class SingleClickTextBox: public TextBox
{
protected:
   virtual void OnClick( EventArgs^ e ) override
   {
      this->SelectAll();
      TextBox::OnClick( e );
   }
};

// This is a custom TextBox control that overrides the OnClick method
// to allow one-click selection of the text in the text box.

public class SingleClickTextBox: TextBox

{
    protected override void OnClick(EventArgs e)
    {
        this.SelectAll();
        base.OnClick(e);
    }
}

' This is a custom TextBox control that overrides the OnClick method
' to allow one-click selection of the text in the text box.

Public Class SingleClickTextBox
    Inherits TextBox

    Protected Overrides Sub OnClick(ByVal e As EventArgs)
        Me.SelectAll()
        MyBase.OnClick(e)
    End Sub


End Class

下面的代码示例演示事件和事件处理程序的 Click 众多用法之一。

   // This example uses the Parent property and the Find method of Control to set
   // properties on the parent control of a Button and its Form. The example assumes
   // that a Button control named button1 is located within a GroupBox control. The 
   // example also assumes that the Click event of the Button control is connected to
   // the event handler method defined in the example.
private:
   void button1_Click( Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {
      // Get the control the Button control is located in. In this case a GroupBox.
      Control^ control = button1->Parent;
      
      // Set the text and backcolor of the parent control.
      control->Text = "My Groupbox";
      control->BackColor = Color::Blue;
      
      // Get the form that the Button control is contained within.
      Form^ myForm = button1->FindForm();
      
      // Set the text and color of the form containing the Button.
      myForm->Text = "The Form of My Control";
      myForm->BackColor = Color::Red;
   }

// This example uses the Parent property and the Find method of Control to set
// properties on the parent control of a Button and its Form. The example assumes
// that a Button control named button1 is located within a GroupBox control. The 
// example also assumes that the Click event of the Button control is connected to
// the event handler method defined in the example.
private void button1_Click(object sender, System.EventArgs e)
{
   // Get the control the Button control is located in. In this case a GroupBox.
   Control control = button1.Parent;
   // Set the text and backcolor of the parent control.
   control.Text = "My Groupbox";
   control.BackColor = Color.Blue;
   // Get the form that the Button control is contained within.
   Form myForm = button1.FindForm();
   // Set the text and color of the form containing the Button.
   myForm.Text = "The Form of My Control";
   myForm.BackColor = Color.Red;
}

' This example uses the Parent property and the Find method of Control to set
' properties on the parent control of a Button and its Form. The example assumes
' that a Button control named button1 is located within a GroupBox control. The 
' example also assumes that the Click event of the Button control is connected to
' the event handler method defined in the example.
Private Sub button1_Click(sender As Object, e As System.EventArgs) Handles button1.Click
   ' Get the control the Button control is located in. In this case a GroupBox.
   Dim control As Control = button1.Parent
   ' Set the text and backcolor of the parent control.
   control.Text = "My Groupbox"
   control.BackColor = Color.Blue
   ' Get the form that the Button control is contained within.
   Dim myForm As Form = button1.FindForm()
   ' Set the text and color of the form containing the Button.
   myForm.Text = "The Form of My Control"
   myForm.BackColor = Color.Red
End Sub

注解

引发事件时，将通过委托调用事件处理程序。 有关详细信息，请参阅 处理和引发事件。

OnClick 方法还允许派生类对事件进行处理而不必附加委托。 这是在派生类中处理事件的首选技术。

继承者说明

在派生类中重写 OnClick(EventArgs) 时，一定要调用基类的 OnClick(EventArgs) 方法，以便已注册的委托对事件进行接收。

另请参阅

• Click