Form.Activate 方法

定义

激活窗体并给予它焦点。Activates the form and gives it focus.

public:
 void Activate();
public void Activate ();
member this.Activate : unit -> unit
Public Sub Activate ()

示例

下面的示例演示如何使用 SetDesktopLocationLoadActivate 成员。The following example demonstrates how to use the SetDesktopLocation, Load 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,该窗体包含名为 Button1 的按钮和两个称为 Label1Label2Label 控件To 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

激活窗体后,如果这是活动的应用程序,则会将其显示在前面,如果这不是活动的应用程序,它将会闪烁窗口标题。Activating a form brings it to the front if this is the active application, or it flashes the window caption if this is not the active application. 若要使此方法生效,窗体必须可见。The form must be visible for this method to have any effect. 若要确定应用程序中的活动窗体,请使用 ActiveForm 属性,如果你的窗体位于多文档界面(MDI)应用程序中,则使用 ActiveMdiChild 属性。To determine the active form in an application, use the ActiveForm property or the ActiveMdiChild property if your forms are in a Multiple-document interface (MDI) application.

安全性

UIPermission
用于更改焦点。for changing focus. 关联的枚举:AllWindowsAssociated enumeration: AllWindows.

适用于

另请参阅