Form.Activated 事件

定义

当使用代码激活或用户激活窗体时发生。Occurs when the form is activated in code or by the user.

public:
 event EventHandler ^ Activated;
public event EventHandler Activated;
member this.Activated : EventHandler 
Public Custom Event Activated As EventHandler 

示例

下面的示例演示如何使用 SetDesktopLocationClosedLoadActivatedActivate 成员。The following example demonstrates how to use the SetDesktopLocation, Closed, Load, Activated, and Activate members. 若要运行该示例,请将以下代码粘贴到一个名为 "Form1" 的窗体中,该窗体包含一个名为 Button1Button,两个 Label 控件称为 Label2``Label1To run the example, paste the following code in a form called Form1 containing a Button called Button1 and two Label controls called Label1 and Label2.

static int x = 200;
static int y = 200;
void Button1_Click( System::Object^ sender, System::EventArgs^ e )
{
   
   // Create a new Form1 and set its Visible property to true.
   Form1^ form2 = gcnew Form1;
   form2->Visible = true;
   
   // Set the new form's desktop location so it  
   // appears below and to the right of the current form.
   form2->SetDesktopLocation( x, y );
   x += 30;
   y += 30;
   
   // Keep the current form active by calling the Activate
   // method.
   this->Activate();
   this->Button1->Enabled = false;
}


// Updates the label text to reflect the current values of x 
// and y, which was were incremented in the Button1 control's 
// click event.
void Form1_Activated( Object^ sender, System::EventArgs^ e )
{
   Label1->Text = String::Format( "x: {0} y: {1}", x, y );
   Label2->Text = String::Format( "Number of forms currently open: {0}", count );
}

static int count = 0;
void Form1_Closed( Object^ sender, System::EventArgs^ e )
{
   count -= 1;
}

void Form1_Load( Object^ sender, System::EventArgs^ e )
{
   count += 1;
}
static int x = 200;
static int y = 200;

private void Button1_Click(System.Object sender, 
    System.EventArgs e)
{
    // Create a new Form1 and set its Visible property to true.
    Form1 form2 = new Form1();
    form2.Visible = true;

    // Set the new form's desktop location so it  
    // appears below and to the right of the current form.
    form2.SetDesktopLocation(x, y);
    x += 30;
    y += 30;

    // Keep the current form active by calling the Activate
    // method.
    this.Activate();
    this.Button1.Enabled = false;
}



// Updates the label text to reflect the current values of x 
// and y, which was were incremented in the Button1 control's 
// click event.
private void Form1_Activated(object sender, System.EventArgs e)
{
    Label1.Text = "x: "+x+" y: "+y;
    Label2.Text = "Number of forms currently open: "+count;
}

static int count = 0;

private void Form1_Closed(object sender, System.EventArgs e)
{
    count -= 1;
}

private void Form1_Load(object sender, System.EventArgs e)
{
    count += 1;
}
Shared x As Integer = 200
Shared y As Integer = 200

Private Sub Button1_Click(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles Button1.Click

    ' Create a new Form1 and set its Visible property to true.
    Dim form2 As New Form1
    form2.Visible = True

    ' Set the new form's desktop location so it appears below and 
    ' to the right of the current form.
    form2.SetDesktopLocation(x, y)
    x += 30
    y += 30

    ' Keep the current form active by calling the Activate method.
    Me.Activate()
    Me.Button1.Enabled = False
End Sub



' Updates the label text to reflect the current values of x and y, 
' which was were incremented in the Button1 control's click event.
Private Sub Form1_Activated(ByVal sender As Object, _
    ByVal e As System.EventArgs) Handles MyBase.Activated
    Label1.Text = "x: " & x & " y: " & y
    Label2.Text = "Number of forms currently open: " & count
End Sub

Shared count As Integer = 0

Private Sub Form1_Closed(ByVal sender As Object, _
    ByVal e As System.EventArgs) Handles MyBase.Closed
    count -= 1
End Sub

Private Sub Form1_Load(ByVal sender As Object, _
    ByVal e As System.EventArgs) Handles MyBase.Load
    count += 1
End Sub

注解

备注

当应用程序处于活动状态并且具有多个窗体时,活动窗体为具有输入焦点的窗体。When the application is active and has multiple forms, the active form is the form with the input focus. 不可见的窗体不能是活动窗体。A form that is not visible cannot be the active form. 激活可见窗体的最简单方法是单击该窗体或使用相应的键盘组合。The simplest way to activate a visible form is to click it or use an appropriate keyboard combination.

若要在运行时使用代码激活窗体,请调用 Activate 方法。To activate a form at run time using code, call the Activate method. 您可以使用此事件来执行任务,例如根据窗体未激活时对窗体数据所做的更改来更新窗体的内容。You can use this event for tasks such as updating the contents of the form based on changes made to the form's data when the form was not activated.

有关处理事件的详细信息,请参阅处理和引发事件For more information about handling events, see Handling and Raising Events.

适用于

另请参阅